Man Trans stuck in gear
 

Thanks for the help.

I have a 63 3/4 ton, with the four speed with 1st being the low range (I think is how it is). Anyway the truck ran great and shifted great for me but while at the body shop I guess one of the kids got to messing with it and somehow got it jammed in what I think is second gear if you count them as all four gears. First gear if you call low and then three forward gears.

So what is the best way to get this thing un-jammed?

Any secret magic, rocking the truck in gear free anything up? I am pretty certain the drive-train has never been apart and I don't think there are a lot of miles on the truck. How they got it jammed up is beyond me.

Thanks again.

Jay

Re: Man Trans stuck in gear
 

Have you started it in gear and driven around a little ?

Re: Man Trans stuck in gear
 

Cecilia does this from time to time if her linkage is out of alignment.

Pop the hood. On the steering column you'll see where the transmission gear rods connect. It kinda looks like two double-sided hammers. One side will be down, the other side will be centered. Put on a pair of gloves, it can pinch.

Then just pull up on the thing that is down. You might have to rock the truck a little to get it to move if the gear is under pressure.

Re: Man Trans stuck in gear
 

Don't think he has linkage. SM420. Lineman, you have a Hydraulic clutch I believe. Clutch fork on passenger side. You must see if this is operating. Quick check: does truck roll with clutch pedal down? No? it's your clutch system. Yes? it's the tranny. (probably)...Anyway, don't know your expertise so will stop there until you advise you need explanation. You forgot to say it's 4X4. Is it factory 4X4 or something else?
Is there normal resistance against clutch pedal when you push it down? No resistance? Real stiff? I wouldn't do that start thing just yet.

Re: Man Trans stuck in gear
 

Hey guys, thanks for the help.

Sorry for the lack of info, it's a 2WD top loader. Hyd clutch, I drove the truck around a fair amount and the thing shifted great. Left it at the body shop and I imagine one of the kids got to messing around moving it and got it jammed up somehow. I moved it since its been stuck and the clutch seemed to work fine, didn't drag at all. Is why I wasn't thinking about the clutch I guess. Was thinking rocking while in gear with someone holding pressure on the shifter might free it up?? Maybe, Maybe not? Or just pulling the collar and he shifer out will that be enough to free up that shifter fork? Or do I have to pull the top off of the trans?

How ugly might this get?

Thanks again

Re: Man Trans stuck in gear
 

If I understand, you moved the truck with the clutch disengaged? Didn't notice any problem with pedal feel?

Not ugly, piece of cake. Can't imagine they busted something. Hope not. If so they owe you repair. Got to be operating like when you took it in.
You can twist off the shifter bayonet retaining cap CCW, Push down hard when twisting, take out shifter, see down in hole and using a tool see if you can slide the sliders a little. Align all the slots in the sliders up with each other for neutral (Rubick's Cube). Notice how the nose of the shifter lever fits into the slots. The nose moves each of the three sliders during shifting. Put all slots lined up in center of peep hole while clutch pedal down. Let up on clutch pedal all the way carefully, see if truck rolls. If it rolls, install shifter. If it does not, change location of the sliders a little but keep them lined up. If a slider won't move, move another slider while trying to move it. If slider still won't move, report back. If you are in 2nd, the center slider slot should be up towards motor. I think that is what you will see. Pull it back into center position with the other two.

Re: Man Trans stuck in gear
 

Thanks for the help. I was at the shop last night fooling with the truck. I didn't have the motor running but the clutch seems fine the best I can tell. I had somebody rock the truck and I did everything I thought I could do while they were rocking the truck while I was pushing around on the shifter hoping the stars would line up at the right time and un-do whatever they did. I have been lucky with bigger trucks stuck in a bind before.

So I hear your instructions and I am sure it will make since once I get the shifter out. I am pretty sure its stuck in second gear if you call it a four speed. First gear if you call it a three speed with low range.

I will print your instructions out and try to get all that stuff lined up and see what I get and get back with you.

Also I was looking for a shifter boot and somebody said it was just a foam piece on top of the transmission, I think that has deteriorated and wasn't there something on top of that also? While I have it apart what should I be doing with that to make it nice?

Thanks again. Jay

Re: Man Trans stuck in gear
 

This goes under the trans floor cover. It's been said that this is possibly "too short", that may mean too thin. You may need two or make one from proper foam. Buy two, they're cheap. Sits on top of trans and compressed by cover to seal. Boot adds more seal and trimmed look.
http://www.classicparts.com/1941-87-.../#.WEBThOnrs5s

Boot. Many types available. It's been said that no boot was used. I use boots and many Chevy and GMC guys do also. This one fits perfectly over the SM420 shifter boss and looks nice. The rubber is probably old Chinese shoe soles and does not last a long time.
http://www.classicparts.com/1941-66-.../#.WEBTy-nrs5s

I see you asked the same question another post RE: Boot and sponge. Now you have the Full Monty.

The above listed company has a good return policy, I.E. "for any reason". If it does not fit or perform properly you are protected.

Re: Man Trans stuck in gear
 

Thanks again. Speaking of that other post, did you see the doughnut looking thing "gmcollector" came up with? Looks like he has the original part? I googled the part number the best I came up with and couldn't find anything on that so I guess these repro parts will have to do. Better than what I have now and the referral means a lot. I am good with that, you guys have these trucks and engines figured out.

As much as working on them is finding all the parts and the best parts etc... Thanks for the help. I need a personal shopper for this truck.

I have to say on top of this truck and get it out of this body shop, time is money there now that they are finally working on it.

Re: Man Trans stuck in gear
 

I don't think you will find one like gmccollector has but you can't see it anyway so you are just sealing in a place where no man goes.

We are good about finding parts on here. This is the place to post and find out what and where to buy. Sometimes it may depend on budget and how much of a GMC purist you are. I like finding parts so ask away anytime.

Re: Man Trans stuck in gear
 

Hey guys, thanks for the interest and the help.

So I pulled the shifter and tried to line some stuff up in there and didn't get anywhere with that. I think I found out why when I pulled the top off the trans.

This trans has the E-brake lever on the right side attached to the top cover. So we did our best to just lift the top cover and slide the gears in neutral and put the cover back and after several tries we were unsuccessful. We were finally able to find the room between the trans and the body to get the top of the trans completely out you must have to have your tongue just right but when its ready it comes out and goes back fine.

So here is what was wrong, is was the reverse slide in the top of the trans. Somehow the shop got the mechanism out of sync in the top of the trans apparently between reverse and what I will call first gear and we had to help the mechanism in the top of the trans in the neutral position with a hammer. Once all three of those slides in the top are in a neutral position and then all the collars in the trans have to be in a neutral position with the reverse lever going to that cluster of gears in the bottom lining up with the neutral potion you just put in neutral in the top of the trans when you put it all together you should be home free.
We had two people, one holding the top of the trans and the other lining things up on the right side of the trans paying attention also to the reverse lever as things went together.

Hope this helps somebody down the road, I think its the first time I have ever had the top off of a transmission but cant me sure as my memory cant be trusted. The guy with me is an excellent mechanic and he never had one of these apart to it took us a minute to figure out that the reverse mechanism was what was jamming things up. I was surprised we had to beat the top slides into position, but it was just a tight transmission I think. When you get it all apart and start figuring things out it will start making since. I anybody has any questions PM me and we can talk about it as I assume you wont be close enough I can come help.

Re: Man Trans stuck in gear
 

I think I know what you said but there is a large access, floor sheet metal transmission cover and there is a actual top to the transmission. I assume you first tried to align the slides just thru the small shifter hole? Then took off the floor transmission cover, then took off the top of the transmission? I understand you have a Trans Band type ebrake, not a under dash horizontal ebrake lever. Maybe you have some kind of carpeting and didn't remove the floor access cover?

Re: Man Trans stuck in gear
 

Thank you for correcting the instructions you requested I post. I did the best I could with my public high school education.
I did not feel the need to talk about carpet, foam doughnut seal on top of the transmission, bolt sizes nor re sealing and I probably should have mentioned the removable floor pan over the top loader for access. Although I think that if someone finds themselves in this situation these steps become obvious during the course of the repair so maybe their mention is either irrelevant or they confuse things with too much information. Guess that is your judgement call there?

Thanks for your attention to detail.

Jay

Re: Man Trans stuck in gear
 

Not your fault Jay, My fault. Just did not understand this part. Thought that the floor cover hole was big enough for this step. Good job.
Happy Holidays!



"We were finally able to find the room between the trans and the body to get the top of the trans completely out you must have to have your tongue just right but when its ready it comes out and goes back fine. "