VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1937 3-spd trans service, need help..

Hello all!
I have a 590822 3-spd transmission (1937 Chevy pass car) installed in a Gibson tractor, which I am disassembling for service.. I have gotten it all apart except for the last item, the reverse idler shaft. This is the one where you drive the retaining pin INTO the idler shaft to remove the shaft. I have removed the expansion plug, and have driven the pin into the idler shaft, yet the shaft is very solid & not moving at all (the gear itself moves freely).. Is anybody here familiar with this step? Am I missing something? What is the secret to getting the idler shaft out?
Thanks in advance!!

first the plug is removed from inside the case. Then the lock pin is driven deeper into the shaft so the shaft can be slid out. Do not turn the shaft in the process.

Yes I understand that part, and have done that. But the shaft is still not moving. Am I missing something? Is there more to it?
Thanks!

I would then suspect that there is rust build-up or a burr preventing the shaft from sliding out.

I am not sure but if the pin hole in the shaft goes all the way thru you may have driven it in too far and it is locking on the opposite side against the case. Sounds like it is similar to the later 3 speeds and should be driven out in the direction where the plug was removed. Otherwise it's possible to damage the bushings for the gear.

It's been awhile since I rebuilt mine, but I remember struggling to get the shaft out as well.

I used a pair of 90 degree needle nose pliers, several sized punch pins, and a small mirror to look inside the hole shown in the red circle below.

I think I ended up using the pliers to tap the pin back into the shaft from the inside, and since the pin is the same length as the hole in the shaft, getting it centered requires finesse. I'm sure that if you do several of these transmissions, you can remove that shaft in your sleep.

If you have a small mirror, turn the lights off around you, and use a small flashlight to look inside the hole...once you see what it looks like, you'll know what to do.

I have a spare transmission that I will also rebuild, maybe I should make a step-by-step video....

Jim, your photo is spot on. I had to go verify, but the shaft in this trans is solid.
Steve, actually that was what I wondered, did I drive the pin in too far somehow?

Since Reverse gear is least used, there is usually no need for replacement so I leave it alone. The repair manual simply says, "Remove shaft". I guess it's like a Jaguar master cylinder that's designed to assemble but not repair.
After removing all other components from the case, gravity and light tapping on the case, will usually coax the shaft out once the pin is driven in.
The gears from a 37 3-speed will fit into a Corvair trans-axle but they will not function as low is not helical. Also the input shaft is inside the output shaft.
Good luck, Lou

Well I've already driven the pin into the shaft so only one way to go now. The reverse gear is good. The reason I want it out is because the main case is cracked, and repairing is going to need lots of heat.. This repair would not be acceptable in a vehicle, but should be ok in my Gibson.
I suspected that the shaft should be easy to move, which your post supports. Thanks

Jim, do you recall? (or anybody else!)
Between the clutch gear shaft and the main shaft are a number of loose needle rollers. The service manual refers to a set of 14 rollers between the two shafts. I think I've also seen a reference to another set of 24 rollers in this same location. I'm sure the set of 14 rollers is correct, but is there actually a second group of 24 rollers?
(When I disassembled this trans, there were NO rollers in this position. But.. I found 43 rollers laying in the bottom of the case. Yeah, right? And now I understand why the case had cracked. The input shaft has side loading in this tractor, which levered the shaft w/o rollers sideways, which pried the bearing to an angle within its bore, which cracked the case..)

The 1937-1952 trans. had the single row of 14 rolers. In 1953 they went to two rows of rollers to cure the jumping out of high gear problem. THaT seconed row had 24.
The heavy duty cluster gear also had rollers rather than brass bushings.

14 rollers it is then.
Good news! Today I went out to look it over again & decided to go through the motions one more time. Hooked a prybar behind the shaft, and nothin! Put a drift against the front end of the shaft, smacked it, and it slid back into the case!!! Then used finger pressure to slide it right on out of the case! It was simply stuck in place from years of no movement...
Now on with this project..
Thanks to all for the pointers!!

Ah, my seconed post..............but thanks for letting us know the cause.

Does anybody know the size diameter & length of these 14 needle rollers? Measurement suggests them to be .1875" diameter, length unknown. Can anybody verify? or better have any rollers to spare?
Also, sources for these loose needle rollers? (all l find are metric)

The rollers are 3/16" in diameter amd 33/64" long.
They were sold in sets of 14 and also came in a misc. washer and roller kit. I believe I have a kit.

An awesome quick response Gene! And would this kit (or rollers) be for sale? Please let me know? Thanks!

PS: How did you ever know that so quickly? wow!

Will get back to you tomorrow, Tue.