• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

TR2/3/3A pops out on downshift

Share this page

doc50

doc50

Jedi Trainee
Offline
Getting 'old Betsy' out into the sunshine again after a couple long years.
(Getting shot really sucks).
I recall a problem with it popping out of 2nd on ANY downshift. (Rebuilt box, OD). Once I was REALLY on it, backed off....... and had it pop out of 3rd, to my utter dismay. Any thoughts as to a starting point?

(Randalll, thanks for the deal on your hard top, hope you chime in here!)

Thom
1959 TR3 (Old Betsy)
#TS34909L(O)
 
There are only 2 things that will cause a properly assembled tranny to pop out of gear. Those would gummed up detents in the cover, or very worn gears.
 
Do you have a 4 synchro box by any chance? There was a subtle pattern change in the dog teeth & shift sleeves later on; mixing those with earlier parts can make them jump out of gear. But that doesn't apply to the original 3 synchro "crash box".

Otherwise, my guess would be a broken "top hat" bushing. The factory bushing has an oil groove in the section between the "brim" and "crown" of the hat that makes it very weak and prone to break there. Fairly common failure if you like to hit 2nd gear hard. The factory eventually switched to a steel bushing, but IIRC you have to do some machining to use it in the early box.

Certainly worth checking the shift detent force (see the manual, a fish scale works well for measuring) as that's a lot easier than pulling the gearbox out to check the other things.

PS Here's a photo from the Buckeye Triumphs site, showing a new top hat on the left and a broken one on the right.
Gearbo10.jpg


Also worth noting that replacement bushings are sometimes supplied too small (or too large), so be sure to check them. I wound up having to reuse the 3rd gear bushing last time, as my old one was better than either of the new ones.
 
John, thanks, I'll look into that.
Randall, wish you lived next door. I'll yank the top cover and take a first look soon.

Thom

'Old betsy'
1959 TR3A
#TS34909L(O).
 
You confirmed what I thought about being shot, glad to see you are better and driving your tr3. I always feel better driving a tr3!
 
Back
Top