Diff drive shaft play

[MetBlue]

My 155,000 miles Differential has about 0.6mm measurable vertical movement on the output shaft - both sides the same.


Sorry about the poor photo, but it conveys how / where I'm measuring.
I have a second diff, which I believe has many fewer miles ( around 50K I think) which measures around 0.25/0.3 mm - both sides the same.

In both cases, I'm as convinced as I can be that this is movement only in the location of the drive shaft (i.e. the internal crown wheel shaft is still under good control by the taper roller bearings).
My thinking is that even a brand new set up would likely show some play ( you need some clearance between the bore and the shaft for the oil to do it's job) so I think the 0.25mm diff is probably as good as it gets.

Ordinarily, I'd fit the best diff, but I have a dilemma - the better diff is off an early car, so a different final drive ratio.
That all said, as long as the output seals are holding - which they are, is 0.6mm vertical movement really a problem? I can't see that it would be, but appreciate thoughts of the forum.

I will be trying one of the "newer" output shafts in my old diff later to see if wear is predominantly in the bore, the shaft or equal to both.

[John]

The parts drawings show the output shafts as having taper roller bearings, and they list many different sizes of adjustment shims. I would guess that the play is due to wear in the bearings given the high mileage, and that you would need to either fit new or just reshim the existing bearings to take up the play.

My copy of the workshop manual includes a section on diff overhaul, I'll have a look later today to see how the shims are selected and what degree of play is acceptable. Will post in due course.

Cheers

John

[Pete Boole]

The crown wheel carrier has the tapered roller bearings and shims. The output shafts just slide into the crown wheel carrier itself. But you're right John - if the crown wheel carrier is moving too much the output shafts will move with it.

Pete

[MetBlue]

I've got the manual John.
I tried the 'better' output shafts on the old diff and got 0.6mm of movement, so does appear the movement is either wear in the carrier bore, or play in the crown wheel between the bearings.
Currently rebuilding with the 'better', but wrong ratio diff. Maybe then the back plate comes off the old diff to check the bearing end play.

[John]

Hi Tony, I can't get my head around the bearing and shim arrangement. SJ list the shims but not the bearings, and the manual suggests that if the play is greater than 0.2mm the output shaft has to be replaced. That suggests excessive play can't be resolved by just fitting new correctly shimmed bearings, which sounds odd unless the play is wear in the shaft itself.

[bash]

Amazingly you can still buy new ones.
TOYOTA SUPRA Shaft Diff Genuine JDM OEM 41309-14060 | eBay UK https://share.google/BoVl5iXvu0sTVsNns

Bash