TR6 TR6 Jumping out of Reverse

[bailee2]

Any ideas on why the (A-OD) transmission would jump out of reverse?
Happens when it has a load (backing up a hill) or when warm.

After it jumps out of reverse the shift mechanism locks into that gear. If you push the clutch in and stop the engine it will easily go back into neutral.

This started in baby steps after the restoration then gradually got worse. It does not jump out of any gear at any speed in forward or in OD. The Ttansmission was rebuilt years ago and set.

Thanks.
AK in STL

 

[bgbassplyr]

Sounds like the shift fork may have moved on the shift rod, not allowing the gears to completely mesh. Wear on the gear will also contribute to this condition.

Also check that the gear shift lever is not binding on or being blocked by carpet or shift boot.

To check the fork , remove the shift lever and transmission tunnel, then remove the top cover (6 bolts). Check the reverse shift fork and retaining bolt (31 and 33, pg. 92, Vic Brit catalogue). Be sure the bolt is seated and not broken or sheared, and that the fork is not bent or worn.

Visually check the reverse gear to see if the wear pattern is over the full face of the gear or only a portion thereof.

If the problem is in the shift fork, easy fix, replace the defective part(s). Reassembly is the reverse. If it's the gear, remember to hold it in reverse so it won't jump out, and live with it. Otherwise, a gearbox overhaul is in your future.

Open to other ideas by those with similar experience. I'm good, but not perfect.

 

[bailee2]

Sorry had to go out of town. I understand what you're saying.
I will check the carpet/boot first and it thats not it then pull the top and check it out. Hopefully it's the fork or similar part not requiring a rebuild. I had the O/D out four times on my last six and gave up on that car. It baffled my entire car club.
Thanks.

 

[pjsmetana]

Maybe your gearbox oil is too light? 30wt is about as light as I would go, as anything lighter would make it harder to stay in gear. I hear some people have a hard time with the really slick oils too, no matter what the weight (Redline and Amsoil, for example)

 

[Tabcon]

Check to make sure that the reverse light switch on the gearbox is wired correctly. I had the same problem because someone had wired the reverse light switch incorrectly and when I would place the gearbox in reverse, the reverse switch would activate the overdrive and cause the transmission to kick the linkage out of reverse. Try disconnecting your reverse light switch on the gearbox and see if it makes any difference.

 

[hondo402000]

I had an issue with my TR6 comming out of 3rd on decelaration, I ended up changing the trany oil for some reason, the oil was low and once I refilled it I have not had the problem anymore, might or might not be low oil