My diff is sloppy as hell... JZA70 G299 4.10 Torsen

[JZA70 R]

My tailshaft can be rotated near on 1/8 (maybe more i cant remember (its heaps)) of a rotation before the slack is picked up in the diff... im guessing this combined with the slight whining on the fwy is bad and i should be taking the diff to get serviced.

Im curious as to what will be done with the diff. what gets replaced or serviced and adjusted. I dont know how these things work but im curious to know. Im hoping there are a few diff guru's in here that could shed some light.

The car is up on ratchet stands atm and id be happy to pull the 'diff' out and take it to someone but ive got no idea who would be best to take it to in perth.

any suggestions?

Thanks.

[oldcorollas]

41334C gets screwed in or out to set the position of the crown wheel?

the crushtube 42131 sets the position of the pinion?

[madmont]

41334c is a shim which is available in different thicknesses so as to be able to adjust bearing preload and gear backlash. The crushable spacer 41231 is crushed between the pinion bearings when adjusting the bearing preload. My torsen does not have that much freeplay. The noise is usually caused by the pinion bearings being worn. New side bearings and pinion bearings should restore the correct clearances

[JZA70 R]

ok great info, thanks. now should i be taking this diff to any old diff specialist or should i try and source the bearings myself and rebuild it. im pretty good mechanically but have never pulled a diff apart before.

[madmont]

The trickiest part is preloading the pinion bearings without crushing your spacer too much. The bearings may or may not be available from your local bearing supplier. the axle seals from Toyota. .Provided you follow correct procedures you should not have a problem

[JZA70 R]

and with the diff 'sloppy' as it is, is it in a weaker state? ...should i be careful driving around on it atm.

[Norbie]

You will cause accelerated wear on the R&P driving it as is, although if you drive gently it probably won't make much difference.

Definitely get a diff shop to do all the work, setting up a diff properly takes a lot of skill and isn't a job for a backyarder.

[JZA70 R]

Awesome thanks.

[Gavatron]

If the C&P are too worn, there is not much they can do. You can only adjust the position of the 2 to get the correct contact patch so far. C&P's are exxy new.

Don't know if the torsen 'gears' can wear and not mesh properly.

[allencr]

How long has it had the 'whine'? Has it increased recently/significantly? Whines more under a partial/light load then when accelerating? Bearings don't change as much when under load in my experience.
If the ring/crownwheel & pinion was off by much at all, JZA70 wouldn't be writing 'slight whining'!

I don't know what a 'Torsen' is, but in any other diff, 90%{guessmitate} of play will be in the spider gears and the axle splines, and the spider gears won't have any play in most LSD types.

If it's always been there & something you've just noticed, leave it alone. Just drive it.

and with the diff 'sloppy' as it is, is it in a weaker state? ...should i be careful driving around on it atm.

No. Noise = wear & heat, and unless it is being raced, it could last forever or last until there is a real problem, with a bearing or tooth or running dry or whatever

[Mr DOHC]

if none of the above take your fancy,

1. get vid camera
2. rev to redline in 2nd gear and dump clutch
3. repeat till the diff explodes
4. youtube
5. reppage!!!!

[JZA70 R]

its had the whine for ages. the car has been raced at the drags several times, and quite frankly abused in its current state. ive run redline lightweight shockproof oil in there the whole time with a couple of oil changes now and it doesnt seem to have gotten any worse over the years.

to be honest the reason why im looking at servicing it is because im planning another trip to the drags but with street slicks and i want to increase any chance i have of it not blowing up.

it would also be nice to eliminate that whine on the freeway. its not a bad whine but its there and its noticable and it annoys me.

[lexsmaz]

Personally the backlash needs to be checked, otherwise as you said it could end in tears at the drags ... I would be suprised if all the wear is in the bearings, but if it is, it means the contact patch on the crown wheel & pinion is reduced due to the gears further out of mesh, ( hence more backlash ) which means it could be easier to crack / smash the teeth off the gears ..

[allencr]

BACKLASH
There must be at least 50 ways to adjust a rear end WRONG, yet still have the correct backlash! Isn't it only to get a decent deceleration contact patch when the normal contact patch(acceleration) is spot on?