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TR2/3/3A TR3 Gearbox Problem

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C

Coombie

Freshman Member
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I am currently busy with the restoration of a TR3, using components from various different sources. After installation of the gearbox, there was a problem with second gear jumping out under the slightest load. I removed the gearbox, and stripped it down, and ascertained that there was excessive end float between gears. This I addressed by installing a thick shim, to bring the end float to that specified. On re-installation of the gear box, it is now virtually impossible to engage first gear unless extreme force is applied to the gear lever.

Has anyone any suggestions as to what may be the problem, and as to how it may be resolved?

Geoff Coombe
Fish Hoek
Western Cape
Republic Of South Africa
 
The popping out of gear is normally caused by a weak or missing ball detent in the top cover. The synchronized gears are pretty insensitive to end play in general. American cars actually have cups machined into the sliding hubs, which are used to hold the tranny in gear. Popping out of gear in an american car is normally a sign of worn sliding hubs or a shifter not fully reaching in gear. The British box hubs have no such cups in the synchronizer hubs, and they depend on the ball detents to hold the box in gear. The end play would have to be off 1/4" or so to cause popping out of gear not related to the detents.

I am not sure where you could fit a shim, but I suspect that caused the first gear issue. I can't know for sure unless you can relate it to the parts diagram in the manual.
 
I am not a great tranny rebuilder, and the last one I rebuilt popped out of second going down hills about a year after the rebuild plus I could feel the whole tranny getting sloppy; it is a little noise. I contribute the popping out of second on the springs and balls on that slider dealie. I pick through the ones I had and used the best. I probably should have used new aftermarket, but that is a big different story. Anyways, when I pull it out, I will purchase new springs and balls. Mine goes into first and reverse fine, but sometimes I need to go into second then straight into first.

Sounds like you should take out what you put in for distance float piece and check the shifting tower ball and springs and slid deal spring and balls. Me, I would replace the slider springs inside the trans on the slider deal and omit the float washer and see what happens. if you have an extra shifting tower try that. These are old units that have been driven hard and hung up wet. Some say the type of oil you put in makes a difference also.
 
CJD said:
The popping out of gear is normally caused by a weak or missing ball detent in the top cover. The synchronized gears are pretty insensitive to end play in general. American cars actually have cups machined into the sliding hubs, which are used to hold the tranny in gear. Popping out of gear in an american car is normally a sign of worn sliding hubs or a shifter not fully reaching in gear. The British box hubs have no such cups in the synchronizer hubs, and they depend on the ball detents to hold the box in gear. The end play would have to be off 1/4" or so to cause popping out of gear not related to the detents.

I am not sure where you could fit a shim, but I suspect that caused the first gear issue. I can't know for sure unless you can relate it to the parts diagram in the manual.
Click to expand...
Thanks for the prompt response I'll give it a try.
Regards, Geoff.
 
sp53 said:
I am not a great tranny rebuilder, and the last one I rebuilt popped out of second going down hills about a year after the rebuild plus I could feel the whole tranny getting sloppy; it is a little noise. I contribute the popping out of second on the springs and balls on that slider dealie. I pick through the ones I had and used the best. I probably should have used new aftermarket, but that is a big different story. Anyways, when I pull it out, I will purchase new springs and balls. Mine goes into first and reverse fine, but sometimes I need to go into second then straight into first.

Sounds like you should take out what you put in for distance float piece and check the shifting tower ball and springs and slid deal spring and balls. Me, I would replace the slider springs inside the trans on the slider deal and omit the float washer and see what happens. if you have an extra shifting tower try that. These are old units that have been driven hard and hung up wet. Some say the type of oil you put in makes a difference also.
Click to expand...
Appreciate your speedy reply. Will crack on - I know I've been putting off the inevitable, the box will have to come out!
 
Hello
If you took apart the first gear you may have put it together incorrectly. It has a ball and plunger in the assembly that can only work right if it correctly installed. When you look at it there are three ball and springs and there is a space that lines up in the assembly that has to be inline with the ball and plunger or it will not shift or is very hard to make it shift.
regards Barry
 
The best approach is to convert to 5 speeds with the Supra /Eaglegate conversion (that I now own)
the best place for a tr3 tranny is under the bench waiting for the day when a Tr3 is a million $ car.
 
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