E34 525iX Diff question

Post Mon Oct 31, 2011 2:33 pm

Got an E34 525iX diff here but im a bit confused. There is an S on the diff case also the tag reads S 3.38 but the output shafts turn like an open diff, ie one goes one way and one goes the other

Didnt have time to get the back plate off hence the topic.

Iirc torsen diffs act like an open when turning by hand, is this what ive got?

TIA.

Post Mon Oct 31, 2011 4:15 pm

I think they are one of them there torsen diffs indeed..

Post Mon Oct 31, 2011 7:00 pm

Just got back from locking the unit and while i was there i had another quick look, there seems to be a brake line type pipe near one of the output shafts with a bleed screw.

Post Mon Oct 31, 2011 11:01 pm

Its a hydraulically lockable diff, I hope you didnt pay much for it

Post Mon Oct 31, 2011 11:08 pm

It was given to me.

Hydraulic, does that mean when fliud gets pushed into it it locks up? Do you know what % they lock up to?

Post Tue Nov 01, 2011 10:58 am

Is it a rear diff?
If so, it is hydraulic, as stated...Operates off a high pressure feed from the rear of the steering pump via an accumulator tank mounted on the front right hand wing. This is electronically controlled via a control module...

Basically, unless you are going for a complete 4wd setup, this diff isn't a lot of use other than as a spare for an iX.

Front diff on an iX is a simple open job...sits hard up against the sump on the left side with the RH driveshaft running through the (unique) sump.

Post Tue Nov 01, 2011 10:59 pm

Thanks.

Being a 3.38 could the crown wheel and pinion be taken from it to use in an E30 diff? seems the same size as an E30 diff also 8 bolts holding the back plate on.

Post Wed Nov 02, 2011 9:53 am

leeparkes wrote:Thanks.

Being a 3.38 could the crown wheel and pinion be taken from it to use in an E30 diff? seems the same size as an E30 diff also 8 bolts holding the back plate on.

This was suggested to me by Gareth when I was looking for a high ratio diff.
Ratio is about right for M50/52 using the ZF 'box....

Post Wed Nov 02, 2011 2:25 pm

Its in line for my torquey M30 B10.

Post Sat Nov 05, 2011 12:51 pm

My 3.38:1 diff had a CW&P i pulled out of one of these diffs

So yes, it can work. Felt a bit tall geared for me on track but then my car is a lot heavier than yours. I'm now running a 3.64 again.

Strange diffs these, they use a hollow hydraulic cylinder to close the clutch plates up, not ramps etc.

I reckon a hydraulic handbrake lever could be used to make an instant 'welded' drift-diff

Post Sat Nov 05, 2011 5:27 pm

gareth wrote:I reckon a hydraulic handbrake lever could be used to make an instant 'welded' drift-diff

This has crossed my mind.