Re: '65 GMC 1500 project. From the Netherlands
 

The camshaft has been sent out last week for regrinding. Hope it doesn't take too long.
In the meanwhile, there are smaller jobs that needed to be done:
-Leaking rear axle wheel seal (replaced both sides, those were one old seal and one seal with an adapter ring I made. The adapter ring started to leak unfortunately, so I took it out and replaced it with the correct seal)
Cleaned out the axle hubs and bearings as well. Bearings are from Timken, made in the USA. They look absolutely spotless. Replaced the rear-end fluid a few weeks ago.
-Clean up the alternator to make it match the new engine. Sandblasted and repainted the fan and used steel wool to clean the aluminum housing.
-Repainted the voltage regulator cover.
-Repainted the pulleys and fan. Wasn't happy with the first try.
-Repainted the valley cover, also do touch-ups on the intake manifolds and heads.

Now it is the time to tackle these tasks. Man, I miss driving the old beast. Should be fun with the new engine.

Re: '65 GMC 1500 project. From the Netherlands
 

Completed all the tasks from the last post. Now onto cleaning up some of the wiring, and installing items such as the AFR meter. Hope to complete the exhaust downpipes this week as well.
Then onto some small jobs, that still needed to be done.

Communication with the camshaft grinder hasn't been too great, still waiting. Companies here are not great to deal with. Wish we had a company like Delta Cam here.
The issue here was that they take apart their camshaft grinder for cleaning every 10 years or so. Guess who wanted to grind their cam while they had the thing apart? So they told me it would take a month to put it back together. That was on the 24th of May. 24th of June has since passed, and more than 2 weeks have passed since then.

In the meanwhile, Steve (tbucketnut) has helped me a great deal by sending out his spare sent of lifters to be reground by Delta Cam for me. Much obliged Steve, and I'm looking forward to them.

If this camshaft grinder doesn't work out, I'll be sending the camshaft to Delta Cams as well... Hopefully, it does not have to come this far.

Re: '65 GMC 1500 project. From the Netherlands
 

Steve told me that he brought some 305 V6 camshaft cores to Delta Cam. I called them and asked if they could grind one of those for me. About a week turnaround time they told me. Hope this all works out. They do ship worldwide.
I also gave them my custom grind specs to grind on the camshaft.

I canceled the order from the other company.

Man, I can't wait for the camshaft to arrive here.
Running out of small jobs to do in the meantime.

Re: '65 GMC 1500 project. From the Netherlands
 

Here is the exhaust downpipe work. I reused the old exhaust flanges that I faced on the lathe. I reworked existing gaskets to fit this application. A pipe reducer from the stock 2.5" to 2.25" was then welded on. The rest of the exhaust is 2.25", which should be plenty of exhaust for this application.
In the picture, the left side is fully welded but the right side is only tacked together. This is now fully welded as well. Quite a route getting around this oil filter. Exhaust work is fun to do, once you get the hang of it. It is a shame that when you finally get the hang of it, the exhaust is as good as finished.

I used a pipe reducer to create the slip fit for the rest of the pipes. A clamp is used to create a gas-tight seal.

My welding skills are not quite good enough to lay a continuous bead on a thin-walled exhaust pipe without creating holes... So this is a fish-eye paradise for the welders.

In the second picture, you can see the position of the O2-sensor. The nuts are still to be welded on, someone will TIG-weld these for me. Both pipes have a nut for the O2-sensor but only can be used at a time. A threaded plug is supplied and screws into the nut in place of the O2-sensor.

Re: '65 GMC 1500 project. From the Netherlands
 

Coming along nicely. I take it you have a planned electronic FI system planned correct?

Re: '65 GMC 1500 project. From the Netherlands
 

Thanks, Steve. The O2 sensor serves as a display instrument only for now. The engine will run most of its life on propane, and this is fed via a mixer to the carburetor. The system is from Impco. It is a dual fuel system, implying that gasoline can still be used.

Here is a video I made showing off my propane system:

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Liquid propane injection with injectors is possible but would require a custom manifold. I like the simplicity of this setup.

Re: '65 GMC 1500 project. From the Netherlands
 

Another update. Delta Cam should have the camshaft finished today, or Monday next week. Hope to receive it the week after. Lifters are also still on the way.

Been busy working on the GMC. The exhaust is pretty much finished. The O2 bungs were welded on for me - beautiful work. If this exhaust ever rots out, I'll let her TIG weld the whole exhaust for me :upyes:
The O2 sensor and the gauge are installed and it all works.

Been busy with the carburetor - managed to score a 500 cfm Holley locally for cheap. Basically a brand new carburetor. It has 61 jets now, which are probably too small. I did some looking around on the forum, most seem to use 68s for the 305. Pete said that the stock 73s worked well with the 478, so that's what I'm using as a baseline. Should it run too rich or lean, I can adjust jet sizes according to the O2 sensor readout.

On Amazon, they said that they shipped the jets to the Netherlands, turns out they do not. So have to ask some local guys if they have Holley jets.

It also has a no. 8 power valve, ie. it opens at 8" Hg. From what I've read the power valve should open at half of your idle vacuum, so 8 seems about right. It also has the stock 30cc accelerator pump.

This does mean that I'm plugging off the governor line, which I first intended to keep in place. I am playing around with the idea to hook a normally open oil pressure sender to the governor line, and if it senses oil pressure a buzzer would sound indicating you hit the redline. Though a nice tach would be better. Would love to have a nice vintage tach on the steering column. Any tachometer recommendations, let me know.

Made a nice adapter flange to use the 478 manifold, but am running into hood clearance problems with the propane mixer. Decided to go back to the 305 manifold, and use the available Mr. Gasket adapter. I'll be sure to radius the edges in the manifold to allow for more flow to the middle intake runners. The port size is the same on the 305 vs the older 478 manifolds. The difference is the carburetor bolt pattern and the 478 manifold has a built-in spacer - see picture.

Since the Holley uses the standard 5 1/8 air cleaner base, readily made propane mixer adapters are available, so I bought one and modified it somewhat to reduce the height. I corrected the center bolt hole and also made a bushing to better accept the 1/4 thread diameter and nut on the Holley. See picture.

I am resizing the pictures for the forum from now on, so they should enlarge quickly now. Took a while to load before!

Re: '65 GMC 1500 project. From the Netherlands
 

Both ISSPRO and Datcon make 3-3/8" diameter 0-4000 tachs that match our speedometers pretty well. First photo is the ISSPRO in my '62 Suburban. Second photo is the Datcon in the '66 pickup that Clyde in South Carolina owns now.

See

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and

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Re: '65 GMC 1500 project. From the Netherlands
 

Since I'm using the 305 V6 intake manifold, I blocked the heat riser in the intake manifold using the same method as before, which is to mill out a recess for a plate to fit in. They are a light press fit. These block the exhaust gas from the heads from entering the intake to preheat the manifold. This is a modification for propane usage. Though it would work for gasoline as well, but in hotter climates. Cooler air means a denser charge, ie. more power!

The correct Mr. Gasket carburetor adapter is on order, as well as the missing gun rack that was once installed in the truck.

I also removed the governor line.
Scored a nice vintage Sun tachometer on eBay, which was local to me. 15 bucks with 15 bucks shipping. It is a 3000 rpm tach, wish it would have been 4000. Though I should keep it below 3000, the 478 was governed at 3200 rpm.
Old Sun tachometers need a separate transmitter box to work properly. However, I know someone that is pretty handy with electronics, and we're going to see if we can rework one to work directly with the HEI tach signal.

Still waiting on the camshaft and lifters. Still working on all sorts of small jobs that need to be completed.

Re: '65 GMC 1500 project. From the Netherlands
 

Here's a photo of the Sun tach in my '65 Suburban that Dad bought new. He had the dealer install the tach and clock before he took delivery.

Re: '65 GMC 1500 project. From the Netherlands
 

Thanks for the pictures, Ed. That is not the typical Sun tach I've seen in other 60-66 trucks. You're making me want to cut a hole in my dash :ahhhh:

First I'll have to get the thing converted.

Re: '65 GMC 1500 project. From the Netherlands
 

Good news! Delta Cam (finally) finished the camshaft!

This is the custom grind that I wrote about earlier. Reground lifters are also on the way!

Hope to have camshaft here in about 1.5-2 weeks.

Fingers crossed...

I'll tell ya, when I have that bumpstick in my hands, that thing is going into the engine ASAP :upyes:

Re: '65 GMC 1500 project. From the Netherlands
 

Received the reground lifters yesterday. They are very nicely ground and then polished with ceramic media, resulting in a very nice finish. The correct radius has also been ground in, if you put two lifters with the faces against each other you can rock them back and forth. Thank you very much, Steve.

Also installed the missing gun rack. The holes were there, and I like the touch as a firearms enthusiast. Just something an old pickup should have. Can't drive around with guns in the rack though :teehee:
Need to remove that duct tape in the cab, but it is stubborn stuff... Been on there for years.

Also did some mocking up to check all the carburetor linkages. Made a steel fuel line as well. The fuel filter is placed between the frame rail line and this steel line. This prevents the gas in the filter from boiling and flooding the carburetor. I had problems with this in the past.

Re: '65 GMC 1500 project. From the Netherlands
 

Here are the modifications to the 305 manifold. I received the Mr. Gasket adapter. To clean up the gasket surfaces I fly cut them on the mill.

I then opened up the manifold to match the adapter opening. I also radiused the edges of the manifold where it transitions into the runners. It is easy to rough in with the carbide burr, then followed up by a shoeshine motion with a thin strip of sandpaper to dress the edges.

Both modifications should aid in flow tremendously.

As you can see I also installed the block-off plates for the heat riser. They are a light press fit.

Also got new 73 jets for the Holley from a local guy, he had a set of Holley jets. Said I could come back if I need another size.

I have plenty of hood clearance now, but I don't like the look of the stock Impco mixer filter. Toying with the idea to adapt a 1-inch or more dropped base air cleaner adapter on the mixer and use a 14x4 or 5-inch filter to correct the proportions.

The camshaft is on the way, hope to avoid any unnecessary customs intervention so I can install it ASAP.

Re: '65 GMC 1500 project. From the Netherlands
 

I had done the same modification to my intake manifold that you had done for the carburetor flange. However I did flow testing with a head on a flow bench, intake manifold bolted to it, and a Holley carburetor on top of that. The result that I had found is the center cylinders did not flow as much as the end cylinders. However with the stock carburetor all of the cylinder flow about the same (and flow alot less than the Holley). The center intake runner make a sharp turn toward the cylinder. To resolved this, I removed the runner divider between 3-5 and 4-6. Now with the Holley all of the cylinders flow rate are close together.

The other reason I'm improving the flow was I modified the combustion chamber and intake port to improve the air flow and cylinder swirl. Before there was no swirl. Now with all of the modification I had improved the overall flow rate by 10 cfm at .450" lift and the swirl inside the cylinder is 900 rpm at .450" lift.

Re: '65 GMC 1500 project. From the Netherlands
 

Now that you mention that about the runners, James, it reminds me of an old post where you posted some pictures:

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Post 6.

Looking to do the same thing to my manifold, since you've proven it works.

Curious how you removed the divider. Just roughed it out with a carbide burr from both sides?

Also curious about your head porting work. I figured the stock ports should produce some swirl, but apparently, they do not. 10 cfm is a nice gain though. Was that with a 3-angle valve job?

Re: '65 GMC 1500 project. From the Netherlands
 

I used a 6" length carbide burrs and worked it from both ends. I have this intake on my truck now. Road testing it I can pull a steep hill and still have power to accelerate up it. Before I would slow down. I'm planning on placing my truck on a chassic dyno to compare to the stock pull (stock carb, intake manifold, and breather).

First off I have not had the time to see what the results will be from this point on, life happens. All of the work that I have done so far was over a year ago. And I been wanting to get back to finishing it.

In the intake port valve pocket I reshaped the short radius, and some smoothing of the port. After a 3-angle valve job I made sure the transistion from the port to the bottom angle was smooth.

As far as the swirl, I had bolted my flow bench adapter onto the head and scribed the bore onto the head opposite side from the sparkplug. It basically convert the sharp edge (that shroud the intake valve) from the edge of the cylinder to the top of the combustion chamber into a ramp. Making a smooth transistion. The only major problem with this is it lower the compression ratio. There is two processes I will be performing to help bring the compression back up:

1.Cutting the head deck and the block deck. I believed the decks is thick enough not to cause an head gasket sealing problems. Will also need to make sure the block head bolt holes is fully tapped and clean to allow the bolts to go in without bottoming out.

2. Then I am going to offset grind the crankshaft from standard to .030" under to increase the stroke. Then mill the top of the piston to get the deck height back to zero, this will remove most of the dish from the top of the piston.

Both processes should raise the compression to approx. 9:1, hopefully or close to stock.

On another note: Doing the same thing on the exhaust valve (but on both side of the valve) will improve the exhaust flow by 15 cfm, with an open exhaust port. Not able to test this with the exhaust manifold bolted on because the flow bench is in the way.

Re: '65 GMC 1500 project. From the Netherlands
 

Thanks for the reply, James. Time to rework the intake... Seems you gained some hp and torque performing those modifications.

Hope you get around to performing the dyno testing, would be interesting to see. A dual exhaust would also help in your case I would think.

I did the same as you to the 478 heads. The short side was a sharp ledge going transitioning into the valve seat area. I radiused it. Also added the 3 angles.

I like your idea, but how much do you need to take off of the deck to get rid of the dome in the piston? The offset grind sounds good but a lot of work. Then you run into the intake manifold and water cross-over fitment problems...

Re: '65 GMC 1500 project. From the Netherlands
 

I hoping to get about .020"-.025" longer stroke, so the piston will move up .010"-.012" higher in the bore. I facts you might not need to mill the piston if the head gasket thick enough (.055" stock thickness) and it would raise the compression ratio, currently the stock piston deck height is 0.00". I've seen other engine with a piston deck height above 0" because of the gasket providing clearance. They did this because they needed more space for the top land and using a short piston pin height.

The intake flange on the head will need to be milled to allow the intake manifold to sit properly. This way the heads and intake manifold can be swapped with another block.

Re: '65 GMC 1500 project. From the Netherlands
 

Got the camshaft in Saturday! Delta did a good job, but the results ticked me off a little at first as they measured them as a hydraulic camshaft. Therefore the opening and closing points have to be taken at the 0.012" and 0.018" lash settings. Seems they had a core with a little flattened intake lobe, as the intake lift isn't as high as I hoped it to be. I believe the stock rockers are 1.5 as opposed to 1.73 which is written down. We'll see how it runs.

Anyway, this probably being an earlier cam(?) it has very small oiling grooves for the heads. I milled them out and also increased the oiling duration to the heads. I am a firm believer that this is better for the engine and positive valve seals. I will try to bleed the trapped air from the rocker shafts when priming the engine by loosening one of the end bolts.

The camshaft and reground lifters have been installed since.

I am also modifying the intake manifold as per James' instructions to remove the 1-3 and 4-6 dividers. It is a hassle to do, but should provide equal flow to all runners. Should have gotten a Magnum manifold, since it already has the dividers removed. But it would have to be imported and freight will cost me an arm and a leg. Anyway, hope to fire her up this week.

Re: '65 GMC 1500 project. From the Netherlands
 

Over the last few days, I reassembled the engine and front end. Started her up and broke in the cam.

Modified the intake manifold as per James' instructions, thanks for the tips James.

Took her out for a test drive. This thing pulls like a freight train... Literally twice the power of the 305. And amazing throttle response. Had her up to 3200 before I blinked. Need a rev limiter badly, going to buy an MSD 8727CT when the vendor here gets it back in stock. This is a HEI rev limiter that can be set between 3000 and 9900, so ideal for this application.

Also found out that these Walker 18230 mufflers choked up the engine pretty badly. They neck down internally. Immediately ordered Walker 17613 mufflers. These have internal baffles but do not neck down. Advertised as Mega Flow. Should be quiet when cruising but loud when you step on it.

Also found out that the SM420 trans can use new bearings... Never noticed it on the 305 because of the lower power output.

The stock clutch seems to hold up though, which kind of surprised me.

Haven't even tested it on gasoline yet, it should have even more power compared to propane.

So to anyone considering rebuilding a 305... Ditch the thing and get a bigger V6... You won't regret it.

Videos to follow.

Re: '65 GMC 1500 project. From the Netherlands
 

David, can you send a short vid through say through Whats App? I would love to see and hear your engine perform. It sounds really stout. Glad you are happy with the results. Funny how the power restrictors quickly show up like you mufflers. Too bad you are not in the Pacifi Northwest, I have a work area just for rebuilding the sm420's and a rebuild kit ready to go.
Congrats,
Steve

Re: '65 GMC 1500 project. From the Netherlands
 

Hi Steve,

Sure, PM me your phone number (with the country code, ie. the full number) and I'll send you (or anyone else) some videos of the 478 running. Still need to upload them to YouTube.

The SM420 bearing noise was slightly present at first but seems to have vanished now. Maybe because the new gear oil finally has found all the crevices in the transmission. Works like it should now even shifts great into 2nd gear.

I'm going to do a driving video as well, these will follow soon also.

The mufflers make the engine sound like it has a cold, really odd. Didn't have that with the 305. Hope to receive the new mufflers tomorrow so they can be installed.

Tried gasoline today, and got the idle right, about 14:1 AFR. The 73 main jets are too large it seems. The AFR gauge went to 10 when transitioning into the main circuit :ahhhh: and the engine stalled when I let off the throttle. I've set the float level correctly. Probably going to 68's and start there. The power valve opens at 8" HG and the idle vacuum is 15" HG, so right on the money there.

Driving is fun but requires a careful right foot. In 4th gear I can pull from 20 mph to 50 mph in one go, it just pours out the torque like it's nothing. And it'll get a 5000-pound truck moving for sure.

Re: '65 GMC 1500 project. From the Netherlands
 

After all of the intake work on my 305, my main jet is a 71. My truck has a lot more power.

Re: '65 GMC 1500 project. From the Netherlands
 

Interesting. Have to do more testing and experimenting to see what causes the running rich situation.

Re: '65 GMC 1500 project. From the Netherlands
 

Quick video of the engine running:

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Driving video to follow. Haven't messed with the carb jetting yet, it is running really good on propane.

Re: '65 GMC 1500 project. From the Netherlands
 

Been a month, not without its fair share of GMC action...

The bearing noise in the old SM420 started to get worse, figured it was time to do a transmission rebuild. Ordered a rebuild kit and new synchro's that arrived very quickly. Removed the trans and started the rebuild process. Used the solvent tank to clean all the parts, you'd be surprised how much old oil and sludge are present in every nook and cranny.

Disassembled everything, cleaned all parts, and assembled them with regular engine assembly lube, which easily dissolved in the gear oil.

Quite a fun transmission to rebuild. The rear ball bearing of the secondary shaft was pretty stubborn to get off, so I removed the outer ring and cage and welded up the inner race. Using a bearing puller it finally sprung loose.

All the gears looked excellent, but the bearings had a lot of play but did not look as bad as I thought they did. They were still the original New Departure bearings.

Ultimately there is no need to get all the fancy tools as described in the manual, if you use your imagination you can rebuild the trans with a shop press, some snapring pliers, and a set of bearing pullers.

The new transmission sounds and shifts great. Very satisfied with the results.

As for the HEI ignition, I had 2 modules fail in a short time. First the original developed a misfire the night before. The next day it would not start. Replaced with an OEM GM module, it lasted about 2 weeks, then quit on the same note. Now on the 3rd module. Installed it today and it runs well, hope it lasts a while this time. Checked all the wiring for shorts of problems, but couldn't find any. Getting a proper 12V signal to the BAT. Tach port is fine too. The coil and magnetic pickup all check out fine regarding resistance. The only thing that I can think of is the distributor ground, which, using the original hold down, could see why it would cause trouble. I modified the hold-down with some brass pins to improve the ground signal and hold-down ability with the HEI as the base is smaller in diameter than the points distributor.

Nothing else to report other than I am tweaking the jet sizes for gasoline. 73s were much too big, I dropped them to 66s and ran about 13.2 AFR in the main circuit at cruise. Still too rich for me. Probably change them to the original 61s to try and achieve get a 14.7-15 at cruise for fuel economy.

Also installed the new Walker 17613 turbo-style mufflers. These don't have the necked-down internal piping as the old mufflers did. They sound great but are a little loud, though. Might have to quiet them down some.

Seems the engine is fully broken in now, the plugs look great and the valve lash is stable.

Re: '65 GMC 1500 project. From the Netherlands
 

Here are some additional pictures of the transmission install as well as the modified distributor hold-down. The transmission install "bridge" was something I borrowed some someone who made it for his truck, which also has the SM420.

Re: '65 GMC 1500 project. From the Netherlands
 

Where did you get the rebuild kit and synchros from?

Re: '65 GMC 1500 project. From the Netherlands
 

Very nice work as usual. Did you end up buying the Novac kit? They probably have the most complete kit. I bet your synchros looked ok. I have yet to find a really worn one and Ive been through about a dozen Sm rebuilds. They are quite fun to do.

You might find that the 13.2 cruise A/F will be fine. I have a wideband and have done much carb and fuel injector tuning in the past. Striving for the stoichiometric mixture for a gasoline carb engine can be challenge, and found that lean surges will rear its ugly head. I attribute this to the differences in runner intake manifolding. I'm assuming you have one oygen sensor gathering the average of at least one bank if not the entire exhaust?? With that big monster engine, if it is running good at 13.2 I might be happy with that, but I fully understand the need to tinker for sure.

Keep up the good work, enjoy your write ups.

Re: '65 GMC 1500 project. From the Netherlands
 

Thanks for the compliment, Steve.

Indeed, as you said, the synchros were still good, but the wear cannot really be detected other than the "points" of the internal thread in the synchros getting duller, thereby needing more effort to cut through the oil layer on the cone. I have noticed improved shifting times, but this can also be psychological rather than factual.

Ended up ordering the kit from Transmission Parts Distributors in NJ. I ordered from them since they shipped worldwide and had the synchro's. Didn't contact Novak, I contacted them in the past but never got a reply. If I were to do it again I would order the Ebay rebuild kit. Saves a lot of money. I believe all the kits are the same, and the 63 and earlier transmissions seem to have a different front secondary shaft roller bearing. I got 2 bearings in the kit that I did not use.

I did notice that the input shaft bearing in the kit is a C3 style bearing, which is normally only used for 2 press fits (shaft and hub). These have greater internal clearance. Possibly selected for misalignment purposes? The trans has a press fit on the shaft and a loose fit in the case, therefore not needing a C3 bearing.
Anyway, the original New Departure bearing was also of the reinforced type with more ***** and a filling slot to accommodate. The new bearing is just a standard-size bearing, with a standard amount of *****.

I wouldn't be surprised if Novak just splits up the kits with the right parts for the transmission year.

As for the A/F, I am running just below Stochiometric at cruise on propane (around 14.5-15.0, Propane is around 15.2-15.5 AFR stoichiometric) and it runs really well. Idle it set to about 13.5. Haven't had any problems with a lean condition problem (no surges, just constant power @ cruise) so far. This might be because of the propane. Gasoline is kept as a backup only. Indeed, I have an AFR on the driver's side exhaust but could also tap into the passenger side exhaust, have a bung on it as well but it is plugged off now.

I like to tinker around but also try to listen to good advice... it is a fine line for sure.

Re: '65 GMC 1500 project. From the Netherlands
 

Not much to report other than that the truck is running great. However, the pinion bearings start to make a little noise. Via a guy in Germany I managed to score a rebuild kit as well as a 3.54 ring and pinion set! The 3.54 ratio should definitely aid in driveability and has been a wish of mine for quite some time. Granted, they are the cheaper DANA SVL sets, preferred OEM Dana but we'll see how these hold up. Still need a new yoke since the original R&P is 10 spline instead of 29 spline. Will probably order it from Rockauto.

Gives me a proper excuse to pull the old Dana 60, fully rebuild it, and give it a nice layer of black chassis paint.

Re: '65 GMC 1500 project. From the Netherlands
 

Pulled the old Dana 60 today. Went pretty smoothly. Broke off one of the U-bolts, see picture. I'll tell ya, when you're laying under the truck without hearing protection and you're breaking them loose using a big pipe and a wrench, these make a nice bang when they snap!

Glad I took it all apart, the lower axle retainers gathered a lot of crud and were corroding the U-bolts. I am planning to drill out the drain holes to 1/2" or so instead of 5/16". New U-bolts will be installed :teehee:

Got a new Spicer 29 spline yoke to fit the new gear set. Planning to take the whole axle apart and clean everything up, then start with the regear process. I'll use the old bearings as setup bearings, found a nice article describing the whole regear process. It takes a little patience to do it properly but in the end, the result makes it all worthwhile. Should allow me to do 60 comfortably instead of straining the engine. Usually drive around 55 anyways.

Re: '65 GMC 1500 project. From the Netherlands
 

More progress on the old Dana 60. Disassembled everything and cleaned up the outside. Lots of dirt and rust came off. It will be painted with epoxy chassis paint when the axle is finished.

The first step in the process it to make a case spreader. I designed my own, based on the original tool. The Allen head bolts fit into the holes in the differential case.

Man, this thing is filthy on the inside. A black goo of metal and old gear oil has coated the inside.
When I got the truck, it seemed like the 1965 gear oil was still in there. Sure left its mark on the components. The pinion bearings are funnily enough OK, still a lot of small indentations in the races of debris in the oil. The carrier bearings are shot. The non ring gear side has small pits from debris, but the ring gear side bearing has extensive spalling and the bearing also spun on the carrier itself :pullinghairout: Forgot to take a picture! Will do it later.

Luckily the damage is not too bad, it could have been worse...
Time to repair the carrier. Planning to make a sleeve to repair the damaged surface. Will continue tomorrow.

Then I can use the old bearings as setup bearings, and start the ring and pinion installation.

For fun, I checked the gear pattern before pulling the old carrier. The backlash is way out of spec, but the pattern isn't too bad considering its age.

As you can also see, one of the pinion preload shims came out broken. The pinion oil slinger was also damaged (not by me!) Maybe I got a Monday morning differential?

Re: '65 GMC 1500 project. From the Netherlands
 

Very similiar to the Model T Ford rear axles I been pulling apart. Between the 600W grease and the dissolved babbitt the gunk is undescribable. Getting enough of the original Hyatt roller bearings and sleeves (need 4 each) to complete one axle as an extra.

Re: '65 GMC 1500 project. From the Netherlands
 

At least you had gear oil in your. The previous owner of my truck had spindle seals and pinion seal leaking. What they did to fix the spindle is to pack grease in them. Didn't do anything to the pinion seal. When I removed the drain plug, I only got a table spoon of oil. When I open it up, everything was worn out. I had to replace everything.

Re: '65 GMC 1500 project. From the Netherlands
 

Good idea. Bet they will come in handy when you get another axle to overhaul.
Lack of maintenance (even as simple as an oil change, takes 10 minutes) seems to be a common thing...

Re: '65 GMC 1500 project. From the Netherlands
 

Hmm. That was quite the chore I'd imagine... Great solution by the previous owner... Pinion and axle seals are like 30 bucks total and take a couple of hours to install...

Re: '65 GMC 1500 project. From the Netherlands
 

A little insight on the Model T Ford - the engine and transmission shares the same engine pan - couple this to an enclosed drive shaft to the rear axle the engine/transmission oil has a free pass to the differential gears if any leakage occurs past the driveshaft babbitt and brass bushings - believe me when I heard (and believe) they leaked directly after they left the assembly line. Ok, rear pumpkin gets extra gunk from the engine/transmission pass the pinion bearing and raises the level in the pumpkin above the axle shaft level and then the mess runs or creeps pass mutliple thick felt washers that seal them at the wheel hub and drips out the brake drum onto the tire and ends up on the ground. Nothing but a oily, greasily, dissolved babbitt and metal particle infected puddle. But, I love it. :thumbsup:

Re: '65 GMC 1500 project. From the Netherlands
 

And coupled with very crude oils by todays standards it is likely to generate a sticky mess.