rebuild T10 1C 37822121

[Daniel M.]

I'm looking to rebuild my transmission, T10 1C 37822121, on my late model '62 C1. It keeps jumping out of second gear when down shifting. I'm thinking it's the synchro. When looking at rebuild kits one of the sites, Gear Box Transmissions, cautions that it's possible the trans may have different size front and rear bearing. Has anyone seen this to be the case on a '62 C1 trans?
I would appreciate any feedback or guidance folks can offer. Thank you!

[Patrick H.]

I suspect (?) they may be referencing the change that occurred between 1962 and 1963 T-10s.

I did a 63 a couple of years ago, and have a 62 coming up soon.
So far I have purchased my parts from Paul at 5speeds.com:

https://www.5speeds.com/cart/index.php?route=product/product&path=33&product_id=57

Paul is also very good and extremely tolerant to your questions if you have them.
I would give him a call even before you order.

[Daniel M.]

Patrick, Thank you, I appreciate your quick reply, information, and suggestion. I'll check out Super661

Thanks again,

[Christopher R.]

How hard a job is this? A complete rebuild of a T10. Is this something a shade tree mechanic can do? Does it require special tools or test equipment?

[Daniel M.]

Hey Christopher, I have no clue. I'm thinking it's above my skill set. I'll be taking the kit to a professional for the rebuild.

[Harry S.]

I destroyed the 4 speed in my 66 SS when I was 18, long ago. With no experience, I just pulled it apart and started. No camera, just notes and laying the internals out in the order they came out. Cluster, Brass and a few other goodies were in pieces. The rebuild worked well. Did several after that for friends and another for me, kept missing third.

The caution is, if you remove the speedometer gear on the main shaft, take lots of pictures and measurement so you put it back in the exactly same place on the shaft.

Good luck.

[Richard G.]

You will have likely to replace the gear and the slider to repair this. Synchros just speed up or slow down the gears for shifting. They have nothing to do with it jumping out of gear.

[Daniel M.]

Richard, your suggestions as to replacing the gear and slider, I'm assuming the gear that would need replacing is second gear. Am I correct with my assumption?
Thank you all for you input and guidance, it's truly appreciated.

[Richard G.]

Screenshot 2025-03-01 214143.png
Yes, replacing 2nd gear will likely be required. As it mates with the clutch slider, it also requires replacement. (the two pieces work together)
Now you replaced the slider clutch, it has 1st gear built into it on the other side. Now you have only replaced half of the parts for first gear, which gets a lot of use. It becomes best practice to also replace 1st gear also.

The super slick shifting Muncie is a joy and also can be quite expensive. Most have been road hard and put away wet.

[Daniel M.]

Richard, Thank you for the additional information! Used and abused from what I've been told.

Thanks again

[Dan A.]

I'm looking to rebuild my transmission, T10 1C 37822121, on my late model '62 C1. It keeps jumping out of second gear when down shifting. I'm thinking it's the synchro. When looking at rebuild kits one of the sites, Gear Box Transmissions, cautions that it's possible the trans may have different size front and rear bearing. Has anyone seen this to be the case on a '62 C1 trans?
I would appreciate any feedback or guidance folks can offer. Thank you!

I think you will find that as these old T10's accrue many miles over the years this results in wear in the main case. This will be the root of the problem if your shifter pops out of gear when decelerating in second gear. The wear in the front of the case allows the main shaft to move forward on deceleration.

[Daniel M.]

Thank you Dan. Will investigate once we get the trans out.

[Michael W.]

This gentleman rebuilt my T10 in one day complete. Runs great.