The Stovebolt Site Forums The Shop Area Driveline 3 Speed Transmission Synchro Ring Replacement

Hello All,

I am rebuilding a s 3 speed top-loader transmission from a 1947 3100. While making the necessary repairs and parts replacements, I'd like to renew the synchronizers (1st to 2nd was starting to require double clutching, so it's apparent they're worn).

I'm having difficulty with spreading the retaining rings that hold the cones in place. Has anyone found a trick to spreading these to get the cones out?

Thanks for any advice.

Bill

I have used snap ring pliers with the removable tips which are thin enough to get in the slot.
The replacement brass rings are available at several aftermarket sources.
However you may be wasting your time and money trying to replace them.
If you look closely the brass ring is staked from the inside of the synchro drum which causes some of the
brass to protrude into the small holes in the housing. That is essentially what holds the ring in place.
I'm sure that there was some special tooling designed for this process.
Just pressing in the rings won't hold them in place long. You may be better off trying to find a better one.
Fred

Fred,

Thank you for the advice, It was helpful. I agree with your concerns, the friction fit alone concerns me.

I've wondered if that staking wasn't there more for the manufacturing process (machining the brass sleeves in place) as opposed to durability? I've rebuilt my synchronizer with the aftermarket rings and will see how long they last. If there are issues, maybe there is a better staking method?

Best regards,

Bill

If you're replacing the rings anyway, why not use a Dremel tool with a small cutoff wheel to remove the old rings in a few pieces? Getting the new ones in should be a much easier task than removing the old ones. Making some sort of staking tool with a pair of vise grips and a pointed setscrew shouldn't be much of a problem- - - -similar to the tool that's used to stake the safety spring tube in place when rebuilding a 1911 .45 automatic pistol.
Jerry

Jerry,

I've already placed the rings (should have measured the interference, but know it's there: had to cool the rings in dry ice and heat the sleeve to about 150'F and still had to press them in). The new rings are thick such that staking from the inside doesn't seem likely (at least with the tools I have available).

However, I'm wondering if I were to undersize drill through the old staking holes and through the rings, then tap for an appropriately sized brass screw, cut it off/shape it on both sides, then stake the screw. The thought is that a brass screw would be similar strength and wear rate to the brass ring - it should hold it axially and wear along with it against the cone.

Your thoughts?

Bill

Sounds like a plan to me. Be sure to allow for a little rotary movement of the replacement ring, as its function is to assist the shift collar in aligning with the teeth on the reduction gear as the speeds match up. The ring isn't supposed to be rigidly attached to the synchronizer body.
Jerry

If you had to freeze the rings and heat the sleeve and still had to press them together.... unless you intend on working the truck thousands of miles heavy hauling then I wouldn't worry about it. Driving it like the antique it is should not be a problem. Be sure to use 90wt mineral oil. Anything else will damage the brass rings.

Bill,
My intent was to provide some information that was shared with me by a friend and mentor years ago.
He owned and operated a transmission shop specializing in manual transmissions in the greater LA area for over 50 years.
They are staked for a purpose. I have seen several synchro drums that the brass rings have pulled out or are loose.
Of course many things wear out in these units by normal use.
Your repair may last many years as your vehicle doesn't have a lot of horse power and is likely not a daily driver.
All the best.
Fred

Hi Bill,

If you are interested, there is a thread on the VCCA site with the heading "41 TRANSMISSION REBUILD"
that goes into detail about replacing synchros etc.
I've rebuilt a few and always struggled with getting the synchro cones out using various snap ring pliers until I got a pair of Kent-Moore J-932's

Thank you all for your comments and suggestions. Looks like the VCCA rebuild article includes one post were a punch was used to stake the new rings, I thought staking would be more complicated than that. I hope to start re-assembly this week, not certain when I'll get it back in. I'll post my results.
Best regards,
Bill

Can someone give the link to that article so it can be included here, please.

Certainly:
https://vccachat.org/ubbthreads.php/topics/432347/1.html

I hope others find it helpful. Thanks to Clem for pointing it out.

Best regards,

Bill

Thanks!