I have a grumbling noise in my diff, sounds like the front bearing area. I fancy stripping it and replacing the bearings and seals myself. The thing what is putting me off is setting the backlash and preloading the bearings properly. How difficult is this and do i need any special tools. The bearing carriers can be a nightmare to get undone from what I have read but I have seen a home made tool for undoing these.

You can get bearing and seal kits for about £80. I have been quoted £175+vat inc bearings/seals to have it done professionally.

The diff is a 7.5" 3.64 LSD

Anyone successfully done this themselves?

if you can get it for £175 cash i would say get it done professionally, i was quoted £250 + Vat for an LSD rebuild.

who quoted your £175?

The hardest part of the rebuild is not doing the backlash, and preload, that's fairly straight forward. The next to impossable part is removing the pinion, and then re-setting it to the correct depth, this is a critical part of the build, because if you don't get it just so, the CW & P will just eat each other. You can buy the correct setting tools from Ford Germany, but you need deep pockets. To set the pinion depth the tooling is around £500 + vat + P & P. SO if you can get somebody to rebuild it for £175 + VAT I would rip there arm of. I would be very interested in who you can get to do it for that, as the bearings, (Timkin tapers), and the seals are around £85, which leaves just £90 to do the work, and just setting the pinion can take up to 2 hours. Cheers Ray

Road and Race transmissions quoted me that price. They are top people, they also did my 3.38 diff for me when I built the MNR for the same price.
The price quoted was just to replace the bearings and seals on the LSD diff.
They also said that if you pre arrange it with them you can take it to them and they will have it ready for you to pick up in a couple of hours, top service. Thurrock, Blue water and Brands Hatch not far if you want to kill time or I reckon you could watch them do it.


[Edited on 6/11/09 by stuart_g]

once did a part change on a diff in a mini despite beining advised about matching the pinion gear never got it right the diff wound up massive bang .

There was a linky to a full rebuild instruction sheet a few weeks back, cannot find it now but did save a copy, if you want U2U me your email and I will send you a copy.

this is it link

I watched Road and Race merge my 3.62/3.38, everything was very easy except when it came to setting the backlash, loading / unloading. More 'feel' than 'technical'.

As said top guys, even if they work from a Bullock shed and it looks like an explosion in a gearbox factory

Link found above by Kev99 but also emailed.

If you are building up to cover 50,000 miles then you need to get it right, if you are building to thrash around a track and summer fun then do it yourself.

To get the pinion nut off you need a deep, I think its a 36mm socket. I got a shallow socket from Halfords for a couple of pounds, cut the 1/2" drive top off, welded in a bit of 2" tube to extend.

As I was just swapping the crownwheel and pinion over I left the Crown wheel bearings in place, recovered the pinion bearing from the donor casing and drifted in.

Put the crush washer over a bit of tube and gently flattened the 'olive' bit and reused.

When assembling just progressive tightened the pinion nut until the assemble started to just bind, ie easy to turn by hand no backlash.

Then dropped in the crown wheel, adjusted both side with the gears in loose mesh, again util it just started to bind.

Now turn both outer bearings together to move the gears into mesh, as you spin the pinion you feel it start to load, so back off a tad.

Now tap in new seals, job done.

Before starting clean the crown wheel adjusters and soak in penetrating oil overnight. I needed to heat the casing with a blow torch lightly, was then able to work the adjusters out. Do not get overly hot as rubber seals lurk within, just used a rod across the casing and worked by hand.

Regards Mark
Rescued attachment Rod on teeth.JPG