Adjusting a front diff

A simple question..

I 'm going to buy a used phase 1 dual range gearbox from a '98 euro spec forester.
I will have to swap the front differential to a 4.444 to match the rear diff that I use.


Thinking to swap the 4.444 front diff from my defect gearbox in to the "new" used one myself, how do I adjust the front diff? Do I need any special tools?

G'day Casper.

When swapping the pinion shaft over, keep all washers, nuts and shims with the pinion shaft it came with.

After that the main thing you'll need is a marking grease. Bearing blue comes to mind but I don't think that's the right name for it. There's yellow stuff that'll do it too.

You smear this on the pinion shaft or crown wheel. Then assemble the front cases as you would normally. Spin the pinion shaft or diff output stubs a full rotation backwards and forwards.

Pull the gearbox down (or for the dual range leave the gearbox input shaft out of the assembly - this can be used to view the marks etc). Look at marks, refer to the factory manual about correct setting for the pinion shaft location. It should be about right from the donor box to yours. Adjust as per manual instructions. You'll become good at putting the cases together and torquing the bolts in sequence

Once happy with this (can't remember if this is the backlash or preload - I think it's preload.), reassemble gearbox and adjust the diff position with the screw bearing cups. You want a nice smooth operation when spinning the pinion shaft forwards and backwards - always do several rotations to find any high/low spots (if any - there shouldn't be AFAIK).

You can do a marking grease check prior to final assembly to ensure it meets the requirements of the service manual.

Cheers

Bennie

I should add no special tools are needed. A soft vice or two blocks of wood in a vice are needed to undo the retainer nut.

I used 90* circlip pliers to help grab the tabs on the bearing cup. Works a treat!

That's about it.

Cheers

Bennie

If I remember correctly, the backlash is the alignment of the pinion shaft with the crown wheel (0,13-0,18 play) and the preload (0,15-0,25) is to keep the differential tight with the screw bearing cups. Sorry if its not very understandable...

I hope we haven't scared you off Casper!

Cheers

Bennie