Datsun 5 speed locked up

[twas_brillig]

Several years ago, I had a Datsun 210 5 speed rebuilt with the Rivergate kit and installed it in our yellow BE.
A friend borrowed it and had the rear wheels lock-up decelerating at low speed in an intersection. He rocked it backwards and forwards to free it up. He's careful and extremely mechanically knowledgeable and adept. I haven't driven the car since but pulled the engine transmission a couple of weeks back and took the tranny back to the shop. They pulled it apart and advised that everything looked brand new and they could see no sign of any problems.
My buddy sent me this note last year:
" Remember how the bugeye locked up on me a couple times? Well, at a car show on the weekend I met a bugeye guy at the show. Same kit as yours.
Turns out when those datsun transmissions wear, there are internal circlips that thin out and you can end up with the locking up issue.
I can't remember, if you swapped in the other one, but when I mentioned this, he came back with the info.
Nice guy, some kinda senior manager for volvo Canada. used to be leyland and volvos were at the same dealers here in ontario... "

Does anyone have any knowledge or wisdom of this issue? Thanks, Doug

 

[BlueMax]

Was he talking about the sycro springs or snap ring clips?

 

[twas_brillig]

I've got no more information than shown above. Doug

 

[Gerard]

Several years ago, I had a Datsun 210 5 speed rebuilt with the Rivergate kit and installed it in our yellow BE.
A friend borrowed it and had the rear wheels lock-up decelerating at low speed in an intersection. He rocked it backwards and forwards to free it up. He's careful and extremely mechanically knowledgeable and adept. I haven't driven the car since but pulled the engine transmission a couple of weeks back and took the tranny back to the shop. They pulled it apart and advised that everything looked brand new and they could see no sign of any problems.
My buddy sent me this note last year:
" Remember how the bugeye locked up on me a couple times? Well, at a car show on the weekend I met a bugeye guy at the show. Same kit as yours.
Turns out when those datsun transmissions wear, there are internal circlips that thin out and you can end up with the locking up issue.
I can't remember, if you swapped in the other one, but when I mentioned this, he came back with the info.
Nice guy, some kinda senior manager for volvo Canada. used to be leyland and volvos were at the same dealers here in ontario... "

Does anyone have any knowledge or wisdom of this issue? Thanks, Doug

I'm unclear as to whether you mean stuck in gear or in neutral, but the mainshaft won't turn? I've never encountered issues with the circlips but they are so thin already, I can't see how that could make any difference unless they became dislodged. These gearboxes use a different system for baulk rings which involves two springs and 3 inserts to control pressure. I have seen springs break or come out, which will allow the inserts to drop out. In once case, a small chip in the part of the hub that holds the insert allowed one insert to escape, followed by the other two due to the lack of spring pressure. This is something that could cause the gearbox to lock up. The other issue I've seen that could cause what you describe, is the failure of the bearing cage that keeps the balls separated and equidistant in the ball bearing races. When this happens, large pieces of metal can get between the gear teeth and prevent them from turning. The same would be the case with a free shift insert. This is a much more likely scenario, especially since rocking the car could either dislodge or sufficiently gnash the gears together and crush the bits enough to turn free again. In my opinion, either of these are the more likely scenario.

 

[Guest]

I've seen one trans that had the syncro dog spring missing so maybe that's what he's talking about.

 

[twas_brillig]

The shop that did the original rebuild tore the transmission down and could find no signs of wear or damage or indication of why it may have locked up. The chap who did the work conjectured (when I picked it up today) that possibly the shifter may have over-ridden the stops. I'll reinstall and see if it happens again; maybe try some hard shifting in an empty parking lot. Doug

 

[Guest]

The chap who did the work conjectured (when I picked it up today) that possibly the shifter may have over-ridden the stops. I'll reinstall and see if it happens again; maybe try some hard shifting in an empty parking lot. Doug

Seen a Mazda trans do that. It sounds like none of this is good for the axle shafts.

 

[SaxMan]

I used to have a Toyota LandCruiser that would suffer from gear bind in the transfer case if you put it in four-wheel drive on dry pavement. The only way to get the vehicle back into two-wheel drive was to drive it in reverse to unbind the gears. The reason for the gear bind was that the transfer case needs a minute degree of "slippage" between the front and rear axles. Without the slipperiness that you have on off-road or slick surfaces, both the front and rear differential are turning at the same speed, it binds the gears together -- perhaps there is something going on with the rear differential that is causing something similar with the Datsun tranny?