Rear diff 4 matic
 

Can any of the experts tell me if the rear diff is interchangeable between a 1980 124TE 4matic and other 124 estates or saloons? reason being mine is very noisy, whines at about 50-60 mph under load and it appears that only replacement will cure this and will need to look for repacement via a vehicle breaker here in Kent ,England. and is the job reasonably easy to do? Thanks in advance

You'll need a diff from another TE 4-matic. The 4-m cars have a hydraulicly locking rear diff that most other models didn't get. The TE has different gearing than the 300Es so only another TE diff is a direct swap.

Have you tried just replacing the rear diff gear oil with a good quality synthetic?

Different also in that it has two ABS sensors and the 2WD only has one (unless it is an ASR car).

300 4Matic diff
 

Thanks for the info , do you have the diff ? and where are you located?
Reuben

4Matic 124 TE is LSD diff
 

"Have you tried just replacing the rear diff gear oil with a good quality synthetic?"

The 124 4Matic and the ASD differentials are true limited slip differentials, and MB recommends their 85W-90 hypoid gear oil A001 989 17 03 10 formulated for LSD.

Change the diff fluid to that and run it for a few hundred miles or kilometers before replacing the differential.

Replacing the diff doesn't look like an easy DIY job to me, but someone who has actually done it at home will hopefully say something about it.

I reccomend Lucas gear oil, a potential cheap fix.

I used it in my MB and it seemed to be a little quieter (not that it was all that louc to begin with) and in my dana 44 front diff on my suburban and it quieted it right down...its like honey.

Autozoo sells it.