6066 (1960-1966) GMC Truck Club

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-   -   5 speed/o.d. swap comparisons - WC/S10 T5 hybrid, NV4500, A833 MY6, Tremec 3550 Mustang (https://6066gmcclub.com/showthread.php?t=49112)

Chuck78 November 11th, 2015 04:02 PM

5 speed/o.d. swap comparisons - WC/S10 T5 hybrid, NV4500, A833 MY6, Tremec 3550 Mustang
I'm getting back to my neglected 62 GMC 1000 panel after a decade of 4 house rehabs and a trade in interests from 70-81 Camaro to now 1970's Japanese motorcycles (Suzuki GS, Rickman framed superbikes, kz1000/z1/etc).

I need to pull the engine to replace a bad freeze plug in the rear, and at least do all new gaskets if not a total teardown and overbore/valve job/etc. Figured might as well give it the royal treatment and ditch the Saginaw 4 speed (slightly noisy, want stronger trans + o.d.) I swapped into it years ago in favor of a 5 speed o.d.

I want an affordable reliable swap that's not too involved, but I need something that can hold up to hauling, even an occasional car trailer loaded down.

*Tremec TKO500 $$$$$$$$$

*Dodge gasoline NV4500 with bell adapter from Advance Adaptors
-very tough, deep granny gear, very very heavy. I've read the rear engine crossmember needs chopped up substantially for clearance for this trans.

*Camaro/Firebird 88+ World Class T5 with S10 T5
tail section and shifter
-seems much more viable behind a hauler GMC V6 than a standard S10 t5, but have to buy two trannies to find a V8 Camaro/Firebird 88-92 World Class T-5 and S10*T5 tailshaft/shifter donor, and still have a transmission that I'd have to baby if ever hauling a car trailer (not very often, every few years.)

*New Process A833 MY6 4 speed o.d. with standard GM bell pattern
-harder to find, still only a four speed but with better highway gear. originally in GM G10 vans, with the basis of this transmission coming from Mopar muscle cars, so fairly strong.

*Tremec 3550 retrofit from a Mustang (from a yahoo group archived post of mine years ago):

For half of the cost of a new TKO500 and Tremec mid-shifter kit....* The older version of the TKO was called a 3550.* I have a NOS new in box Tremec 3550 for GM applications for my Camaro, as I have previously mentioned.* These trannies also came in a Ford Bellhousing bolt pattern and input shaft, and were used in several years of Mustangs.*
I've been talking to a guy at Modern Driveline, and they can set me up with a rebuild kit for a 3550, as well as a GM 1-1/8" 26 spline input shaft , and I believe I will need the GM diameter input bearing retainer as well, unless the Ford is the same 4-11/16" (doubt it).* They are telling me that the Ford trannies are close enough in bolt patterns that you can redrill a Ford version trans no problem for the GM bellhousing bolt pattern.* Now we're talking!!!! Alright, a viable used tranny that's rated for 425 ft-lbs in a 5200
lb vehicle!!!!* The 3550's weren't as good as a TKO-500, which handles 500
ft-lbs and has a much better shift rail design, but I can deal with tinkering with the shifter and shift rail to make it work for me!*

Chuck78 November 12th, 2015 03:55 PM

Re: 5 speed/o.d. swap comparisons - WC/S10 T5 hybrid, NV4500, A833 MY6, Tremec 3550 Mustang
Well it seems as if the A833 MY6 may be a better consideration after all. After researching a bit, it seems as if the only real difference between the standard A833 & the units they put behind 426 hemi's & 440 six packs was going to a 17t input shaft from a 23 if I recall that # correctly.

I read a review of a guy testing the waters on a $75 junkyard unit to see how tough it was. He put it in a 4000lb V8 Impala or Chevelle, did some drag launches that failed to hook up the tires (3.09 1st gear = mega torque / no traction), so he did the ultimate test that would always be sure to blow up several Muncie's he's had, holding the gas to the floor when shifting, resulting in 5000rpm shifts and chirping the tires in every gear, and the A833 MY6 survived quite well!

Also, this seems to be the same length as a Muncie, which if meant the same length as the Saginaw I have in mine, then I wouldn't have to have the drive shaft shortened whatsoever.

Only big drawback is that hard parts are tough to come by, only used... so running one of these for the long term would probably mean I would need to be scavenging junkyards to pull several of them to have gears/shafts parts available...

Chuck78 November 12th, 2015 04:10 PM

Re: 5 speed/o.d. swap comparisons - WC/S10 T5 hybrid, NV4500, A833 MY6, Tremec 3550 Mustang
Also, the world Class T5 with S10 main shaft & tail/shifter would still only have a lowest first gear of the WC Camaro boxes at 2.95, where as the A833 would have more of a light truck 1st gear of 3.09. The t5 is close to that but not quite, and probably not as strong. Even if it were possible to swap some S10 gears into it for a deeper 1st, the gear ratio alone would reduce the power handling capacity of the t5, and the gears themselves may not be quite as strong.

5 gears & very very common parts would be nicer than 4 with a huge jump from 1st to 2nd, and lesser parts availability, but the my6 makes a very strong case... the t85n and it's scarce od solenoid parts I will save for the more purists amongst us.

Lastly, it seems as if the Jeep AX-15 is now quite the viable swap candidate, except that the 2nd versions are far less common. The Novak adapter plate to mount these to a GM bellhousing says it also works with the New Venture 3550. Is this the same trans, different name/application, or just similar? Is the NV3550 the basis for the Tremec TKO'S predecessor the Tremec 3550 that I mentioned?
A quick Google search said something to the effect that the AX15 was nearly the same as the model that Toyota uses in the Supra or something to that effect. This is definitely something to look into.

if it weren't for the electronic only speedo and integrated bell on the NV3500, that would be the obvious answer.the auto transmission adapter kit for our gmc v6 blocks may work to mate those and extend the crank the proper amount with an adapter, but at $995 + $1000+ tranny, might as well get a TKO.

The NV4500 has been on my mind for years to swap in, quite the brute, but the weight and the tow truck 1st gear made this overkill gmc v6 retrofit less of a consideration.

Chuck78 May 23rd, 2016 05:27 PM

Re: 5 speed/o.d. swap comparisons - WC/S10 T5 hybrid, NV4500, A833 MY6, Tremec 3550 Mustang
Looks like I will start scouring the junkyards for an 81-87 c10 truck or 81-89 van with the np440 "a833 my6" trans. Might be upgrading to a 351E / 351M if I can find one. NV4500 or ax-15 jeep 2wd would be more of the ultimate conversion, but this will be very suitable and easier, and I probably don't have to modify the floor hump at all. The ax & NV look to require the taller floor hump

Chuck78 June 3rd, 2016 12:52 AM

Re: 5 speed/o.d. swap - A833 MY6 "NP440" 4 speed o.d.
Well... the. TKO-500 Tremec transmission ($2450+ $350 more for truck shifter locations) would be the top choice if I had a much larger budget, but after all this consideration, I have done more researching...

The A833 rpo code MY6 "NP440" 2 wheel drive 82-86 c10 chevy truck transmission (& rare 82-89 g10 4 speed vans) would be the perfect swap for me with a Saginaw in place currently, as it would bolt right up!

Note how one shift fork/linkage bracket us upside down from the other. For ease of redesign reasons, when they took the a833 4 speed and converted it to an o.d., they made o.d. the 3rd gear position, with 1:1 still as 4th. They did this to keep the arrangement similar with minimal changes, knowing that they could just reverse the shift linkage and have the shifter hit Overdrive 3rd gear in the standard 4th gear shifter position, and then the 1:1 4th gear would be shifted into in the standard 3rd gear shifter position.

These trannies are incredibly strong. The only downfall is the cases wear at a point where the end of a shaft rides in a register in the case, they get egg shaped. The cases can be machined and a steel bushing pressed in place to repair this.
Another downfall I've read (but not as common) is of the needle bearing wear on the input shafts, primarily blamed for GM's poor recommendation of Dexron III - mercron automatic transmission fluid vs a good gear oil (some say 50W gives much better shifts)
Lastly, for our GMC V6's, we need the more rare version of these. Most came with a GM bellhousing to block pattern, but a special bellhousing that adapted to the odd looking Chrysler pattern on most of these transmissions. Some of them were made with the standard gm transmission pattern, but more than not had the Chrysler pattern with the gm engine adapter bell.
Chrysler bolt pattern version requiring it's exclusive GM SBC pattern bellhousing:

These things are getting harder to find. Some have aluminum cases, some have steel cases. I am not sure of the correlation between 2wd & 4x4, aluminum vs steel, in terms of the likelihood of finding the gm trans pattern that we need to bolt to our gmc v6 bellhousings.

Chuck78 June 3rd, 2016 01:19 AM

Re: 5 speed/o.d. swap - Aisin AX15 Jeep/Dakota trans
I was turned on more and more to the Jeep AX15 transmission + $319 Novak GM bell adapter kit from a sole post from a 60-66 GMC Club member who mentioned in his thread abandoning either the NV4500 swap or A833 swap in favor of the Aisin AX15 + Novak Adapter kit.

Lots of info here:


This is not to be confused with the weaker AX5 Jeep 5 speeds that look nearly identical (they have a steel mid plate vs ax15=aluminum, & were not found behind 4.0&4.2L engines), nor the garbage 2-year-only Peugeot 5 speed Jeep trans, nor the 2 years following the ax15 where jeeps used an nv3550 (90-91/92?).

These ax15's hold up very well in modified jeeps including tons of them that see heavy trail rig 4 x 4 use and abuse. There are some modifications you can do to make them withstand even more power. These are almost identical to the same Aisin transmissions used behind the very powerful turbocharged Toyota Supra, Chevy Colorado trucks, and I believe Pontiac Solstice, as well as an Isuzu application (these go by ar5, am5, & ma5 or mr5 or something like that, NOT ax15, but they are very similar and you can swap guts of some of those to get a 4.02 1st gear ax15 even). Those have different input shaft lengths but I believe the bellhousing patterns are all the same. The tail-shaft housings are all different as well.

Being in Ohio, we get quite a bit of snow some winters, and I have had zero luck finding a 2 wheel drive jeep from 87 through 99 in the junkyards. I was becoming discouraged and was going to look into and old Tremec TKO3550 or figuring out how to afford a TKO500, and read a mention of Richmond Gear aftermarket transmissions, and another company that sells modified refurbished T45 Transmissions, which I have yet to look into.

Then I struck it big! Jeep being Mopar, they also stuck this trans into Dodge Dakota trucks behind the 238ci V6! Due to the fact that Dodge Dakota trucks do not have a massive cult following as Jeeps do, I was not able to find as much info on the Dakota variant, but I believe they were available 1992 through 2004, or 2006, and the only difference was the bellhousing.

The only thing to avoid is the input shaft on 3 years of the Dakota version 1996-1998 that were put behind the 2.5L 4 cyl were 14 splines vs 10. I am not sure if the 2.5L 4 cylinder version had any other differences aside from the 14 spline input shaft.
All of the Dodge Dakota 6 cylinder applications, as well as Jeep 4.0 & Jeep 4.2 liter engine applications will have the proper 10 spline input shaft that we are looking for to work with the Novak adapter plate.

Funny, it seems the plate was made for the opposite reason as why we are intetested in it. I would venture to say that Novak made this plate so that one could swap a GM engine (small block Chevy) onto the Jeep trans. We want it to swap a nice truck ratio o.d. 5 speed into a GM vehicle...

Chuck78 June 3rd, 2016 02:03 AM

Re: 5 speed/o.d. swap - Aisin AX15 Jeep/Dakota trans
These AX15's came behind factory 4.0L & 4.2L V6 Jeeps putting out 280ft-lbs stock & get abused by the modified 4x4 crowd with very few complaints of failures, generally only failures due to wear and tear from people who don't know how to drive stick. One Jeep guy posted that he is making 311ft-lbs dyno'd and has 186,000+ miles on his 4x4 jeep ax15 and zero problems, and says it never gets driven mildly. Good to hear. Our GMC 305 V6's put out about 280 ft-lbs. The 351E puts out about 320ft-lbs. I think with careful use, occasional heavy trailer hauling in my 4000lb 62 GMC 1000 panel truck even if I put in a 351E would work out great. Once every year or 2 I need to tow a car on a dolly or trailer, but a motorcycle trailer will be the more common hauling use. This sounds like the best all around transmission for anyone not needing the serious extra capacity of the brute NV4500, and for normal driving, the 3.83 1st gear will be fairly useable as a 5 speed, whereas if not hauling major loads, the 5.## NV4500 1st gear gets skipped altogether under normal driving and you basically have a much heavier equivalent to the a833 my6 4 speed or 700r4 gearing.

These AX-15's have a 3.83:1 first gear, so this is still a very viable medium duty truck transmission with a gearing that will help with hauling loads.
Most have an electric speedometer output, which makes most vintage car/truck enthusiasts cringe at the black box speedometer conversion piece needed, but fortunately if you remove the electronic speedometer output, you will see the same standard drive and driven gears as what a cable driven speedometer uses, and then you will find that the cable driven speedometer output from many other older Chrysler transmissions bolts right in in place of this electronic speedometer output! Being popular in Jeeps which get modified heavily with different size tires and wheels, all sorts of various speedometer gear sizes are readily available from many sources to calibrate a speedometer.

Novak Adapters sells the adapter plate and many other accessories for this transmission 2 bolt to GM bellhousings. Unrelated to us, advance adapters sells a bellhousing to block adapter to take the Chrysler bellhousing and bolt it to a GM Block. This is of no use to gmc big block V6 power, however.

HERE IS A DETAILED AX-15 SWAP INTO A 1965 CHEVROLET C10, basically same as what ours would entail:


Aisin switched the AX15 to a larger pilot bearing inside diameter, and went from an internal bell slave cylinder setup to external slave cylinder & standard fork. I believe it was 92 on one of those mods (TO/slave cyland 1894 or 95 on the other. Novak sells both sizes of adapter pilot bearings or bushings to mate with GM crank shafts.
I believe the earlier versions were recommended to run GL5 gear oil, but some people complained that in 1997, they modified the transmissions for use with GL 3 gear oil. Apparently, the GL 3 is not even available from Chrysler anymore, and Jeep people complained about this transmission fluid not working as good anyhow. This made me wonder if 94 or 95-96 would be the best years of 4.0L & 4.2L Jeeps to source one from? Used pricing at local yards (pick n pull - $140-180) can be had for pretty cheap, and ebay/craigslist/expensive yards are asking $350-800 for these 2wd versions.

Apparently B&M make an aftermarket short throw shifter for these as well.

Chuck78 June 3rd, 2016 02:55 AM

Re: 5 speed/o.d. swap comparisons - WC/S10 T5 hybrid, NV4500, A833 MY6, Tremec 3550 Mustang
Novak even sell refurbished/modified versions of these for $1500! They show a picture of a 4x4 version, but I emailed them to see if they also have these available in 2 wheel drive, since they said to call or email before purchasing a transmission since there are so many different configurations available. This did not include any of the adapter pieces, but I still thought that was a fantastic price for a fresh transmission.

If doing 4x4 versions, the Dodge transfer case bolt holes are shifted slightly downward, but the Jeep guys say the flange is cast for either pattern, so redrilling for the standard jeep transfer case clocking position is very simple.

I am likely going to buy one of these. If I do find an a833 my6, I might end up using it so that I don't have to shorten my drive shaft a 2nd time, but this ax15 seems like the best in most passenger truck gmc big block V6 applications as long as one takes it easy when pulling heavy loads. The A833 I think may be a touch stronger but lacks the deeper 1st gear for help off the line, & the Jeep crowd really abuse these things with very low failure, so maybe they are just as good for the power?

One last note for this evening, the Chevy c10 swap guy noted that the 2wd version was hard to find a matching driveshaft yoke for, and that it was different from the 4x4 version yoke. Get one from the donor vehicle or else make sure you're buying one from a 2wd Jeep ax15 application. The Dakota 2wd yoke is likely the same.

I will be hopefully swapping one in this summer. May be acquiring one at a great price very soon.

Funky61 June 3rd, 2016 03:35 AM

Re: 5 speed/o.d. swap comparisons - WC/S10 T5 hybrid, NV4500, A833 MY6, Tremec 3550 Mustang
Lots of great info here Chuck thanks!
I look forward to seeing how this swap works out. I have the NP440 MY6 in my suburban and yes it was s journey acquiring the correct parts. I followed the ClassicTrucks article to the letter and it works great.
Looking forward to your swap choice; seems like you've done the research. Thanks again for posting this up.

jturk June 3rd, 2016 02:23 PM

Re: 5 speed/o.d. swap comparisons - WC/S10 T5 hybrid, NV4500, A833 MY6, Tremec 3550 Mustang
5 Attachment(s)
Hey Chuck,
I've used the Aisin AR5 GM code MA5, it's used in the 4 cylinder Colorado and the 5 cylinder Hummers. Put it behind a GMC using an adapter from Novak. This tranny is very similar to the Jeep AX-15. It's gone into a 65 GMC and they are plentiful and fairly inexpensive. I've attached a few photos of it during setup of my build. Good luck with your build.Attachment 4709

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