stira2

iTrader: (1)

Right after stripping fifth in my ra box some months ago I've been on the hunt for a replacement but can't find the exact one (3.9 final,short ratio,r160 rear diff) any way I've been offered a box which also runs a 160 rear diff but has 4.44 final drive.
My question is if I replace the box and rear diff can I take the cusco part of my rear diff and put it in the new one?

Arch

iTrader: (59)

Yes just remove the diff and swap the diff unit into the diff you want too use. Its a case of putting the crown wheel from the diff you want to keep onto the cusco diff unit and refit. It may need shimmed tho.

stira2

iTrader: (1)

How do you mean shimmed? sorry I'm not too up to speed with all of this.

APIDavid

iTrader: (4)

The shims are with the case and are the ones that are needed [ in broad terms ] for your case. So when you take out the crown wheel assembly of the 4.4; the alloy housings either side of the diff main case will have a selection of shims already in there. DO NOT mix them up.

Swap the crown wheel over from the 4.4 onto the Cusco and re-torque the crown wheel bolts properly. Use the best ones from both sets of bolts and make sure they are clean and re-oiled before fitting them.

Some LSD's need a small amount ground off the case to get clearance for the LSD to drop in. That will have to be done carefully as the grinding dust does not want to be in there around the gears and so on. Pack everything with oiled rag or kitchen roll if you need to Dremel a bit off. Then remove the rag plus grinding dust carefully and check how successful you've been

Refit the crown wheel / diff assembly and when the alloy housings are bolted back on with new oil seals and O rings check the backlash [ gap ] between the crown wheel and the pinion This is done dry using a dial gauge on one of the crown wheel teeth and just rock it gently back and forth. It need to be about 4 to 6 thou of an inch or about .001 - .015 mm.

That's when it gets tricky, as if it is too large or small you need to move a, or some, shims from one side of the alloy housings to the other. Depending upon how far out it is - so for instance if you have a lash of 8 thou you need to take a 2 thou shim out of the non crown wheel side and put it in the crown wheel side to move the crown wheel 2 thou nearer the pinion. It is not an exact science and you might need to juggle a few times.Other than the dial gauge no special tools are needed.

Once you have it about right, rotate the crown wheel carefully and check it again at 4 positions to make sure that it does not tighten or loosen through distortion.

If the front seal on the pinion is not leaking leave it alone as the pinion nut is very tight and can be a problem to undo when the diff is in the car, let alone loose on a bench.

Good Luck, David APi

stira2

iTrader: (1)

Thanks for the reply, very helpful. Out of interest what would you charge for doing it?

APIDavid

iTrader: (4)

It's about 4 hours work, so £200.00 + VAT. It's not a job f0r a beginner or the faint hearted. Many 'Specialists' send their transmission work here to be done, you'd be in good company.

Cheers David