The Stovebolt Site Forums The Shop Area Driveline Removing 3speed from my 1950?

Ok,
Can someone give me the basics to removing my 3 speed transmission from my 1950 3100. (Attached to a 1957 235).
The 3 speed is now giving me problems 2nd and 3rd gear. Not going into or coming out of. No grinding. I Triple checked the linkage. So, transmission has to come out. Stock 1950 drive train, torque tube enclosed drive shaft. Thank you in Advance.
Todd

If the engine is already out, the tranny must just be hanging from the u-joint, and may be the rear transmission mount (if it has one.) Support the tranny and unbolt the 4 u-joint ball housing from the transmission. Then you should be able to pull the transmission out of the driveshaft. The rear of the u-joint will slip right off the prop shaft.

No ,
engine is in truck. Sorry for the confusion.
It's All together.
Todd

Before you do anything, disconnect the shift rods from the transmission and attempt shifting gears at the transmission to see if the issue is truely in the tranny or just the shifter assembly. Remember one shift lever must be in neural before the second shift lever will be allowed to move.


If you need to remove the tranny:
If you have an engine hoist, you can use that to help manhandle the transmission thru the cab. If not, you can use a 2x4 (4x4) to span the two doors thru the window with a hoist and a rope wrapped around the tranny. There are two bolts on the top of the tranny and two on the bottom accessed thru the clutch inspection cover. Specific steps and details can be found in the Chevrolet Truck Service Manual here.

Before you do anything, the torque tube must be supported. The 1/2 ton has trunnions at the rear end that enable the torque tube to pivot at the ball joint at the rear of the tranny. If you disconnect the tube from the tranny the tube will be preloaded with the weight of the truck and can cause extreme injuries or even death. You can support the tube with a floor jack or a 2x4 under the tube and resting between the frame rails.

Additionally, clean the front of the torque tube where the universal ball joint and collar slide back onto the torque tube. And when I say clean, I also mean to take some sandpaper and polish that area smooth so the collar slides back easily. Loosening the collar where the seal is also helps.

Phak1,
Thank you.
I will disconnect the linkage and test first.
Todd

Update.::
Linkage disconnected. Problem is in Transmission!
The forward shifter shaft will go into one gear but NOT the other. I made sure the other shifter shaft was in neutral.
Transmission has to come out.
Disconnected the speedometer cable. Now draining the gear oil.
Todd
**Update small pieces of metal on drain plug..

Ok, where can I put a 2X4 to support the tourqe tube? Where can I place the jack on it? Don't want serious injuries or death.
Thank you,
Todd

You can put the jack about anywhere on the torque tube. You'll need to jack it up high enough to be able to move the transmission back to disengage it from the clutch. You may have to lower it down to do that if you can't get it high enough. If you have a crossmember at the back of the transmission (not all trucks do,) that may have to be removed to give you enough room. See attached pic. One option would be to use a ratchet strap hooked over the top of the frame rails and under the torque tube as a sling to hold it up. If you take the weight off the rear tires (by lifting the frame) then there will just be the weight of the torque tube to make it drop instead of the leverage of the weight of the rear of the truck (the pivot point for the axle is forward of the contact point of the tires so pressure on the wheels makes the torque tube pivot downward.)

[on edit] Maybe before pulling the tranny, pull the side cover off and check the interlock between the shift levers. Could be that broke and is restricting the movement of the forward lever. If that's messed up, maybe just repairing/replacing the side cover can fix the problem.

Ok. Put the Jack's on frame and let tires hang? That will release the tension? Then heavy Rachet strap on tourqe tube before unbolting it all. ?
Thank you.
Then go from there?
See pictures I just took.
There is a Crossmember.

***This is pretty good Wear...
Thoughts?
See picture .

Ok,
Everything inside looks good. No broken teeth, ect. It's pointing to the very worn 2 & 3rd gear shifter fork.
Anyone have that GM part number?
Thank you
Todd

Todd - Looks like that is GM# 591783 or 3845048 from Chevy Master Parts Books (extract pics below). Fits 1948-65 1st Design Muncie 3 speeds for the 2nd to 3rd gear shift fork. The original GM# 591783 was replaced by GM# 3845048 on 7-1-1955.

Here are a couple of available now on ebay pieces you might want to snag as either one will work for your transmission.

NOS GM# 591783

NOS GM# 3845048

Great,
I have a late 1950's 3 speed in yard.
I bet it has one!!!
Todd

Yes the 2-3 shift fork is worn but that may be only part of the problem.
Check the ring on the 3rd gear end of the syncro assembly where it is
engaged by the shift fork. If it has excessive wear the syncro is toast.
Another problem area is the brass rings can be loose or worn. It's not easy
to determine wear on the rings without disassembly.
Fred

Fred,
Will check in a bit. Sent you a private message.
Thank you!

My 2-3 shift fork was worn like that also. What I did was weld it and re-machine (actually a friend did it for me.) The trans shifted just fine. But I see you found a spare. 👍

Ok, update on trying to remove the 3 speed.
See pictures. I can not figure it past this. Manual is confusing.
Any good Hints or pointers?
The Tourque tube has a strap on it. The transmission will move Rear about 3 inches..that's it.
Thank you ,
Todd

I think the 3 speed crossmember is bolted in ,if it is that would be the easy way to unbolt the crosmember .I think some of the crosmembers had a cutout to allow the bell joint to go down under ,but maybe that was for the old cars .I noticed in your picture the u joint looks like it is still together .The torque tube bell needs to slide further down on the tube ,you have to clean the tube free of old grease ect and loosen the collar off and slide the bell as far back as it can go then take the u joint off by removing the 4 bolts once that is off you can pull the yoke out and drop the tube further to allow the transmission room to be pulled out.

Yes, the crossmember is bolted in. There are 5 bolts on each side. One is threaded in from the bottom into a captive nut in the crossmember on each end. The crossmember will have to be removed to drop the torque tube out of the way. I don't think it's possible to get the torque tube high enough to pull the transmission with the cab in place. It would hit the floor first.

Thank you.
The Manual only says remove the 4 (four) bolts holding the transmission to the Crossmember. It never says remove the Crossmember. Then it says to jack it up (Torque tube). Not drop.
Probably why I was scratching my head yesterday.
Todd

I could be wrong (that's never happened before ) about not being able to raise the torque tube high enough. Try that first.

Raise the torque tube as high as it will go with a floor jack then cut a 2x4 long enough to fit inside the C-shaped frame and slide the board back until it supports the weight of the torque tube.

Be careful when you cut the 2x4. The frame widens as it goes toward the back, so be sure it's long enough to stay in the frame as you go toward the back to hold the torque tube up.

Update:
Transmission is out.
I did remove the Crossmember to get easy access to the Ujoint bolts. Now I will have to see what went bad in the Transmission.
Thank you all. I will start a new post soon on the tear down and what am I looking for as I take it apart.
Todd