Diff identification.

[Wes]

Having a clean up and my 1972 3.0si automatic donor is off to heaven. The rear subframe is covered in an unholy mess of oil/dirt.
What stampings should I be looking for, to tell what type of diff, as don't want to let any good parts go.

 

[HB Chris]

It’s all right here

Thread 'Speedometer and Differential Ratios'

Jul 28, 2020

The e9 coupes came with three differential ratios and could be found both open or unlocked and locked or LSD. The speedometers were matched to the car based on which differential was fitted.

Differentials

The differential ratio is expressed as a fraction and is stamped on the right lower side of the differential on a flat boss. The presence of a stamped or painted S indicates locked or LSD.

3.25 = 39/12
3.45 = 38/11
3.64 = 40/11

These differentials were typically found on these models:

3.25 Open - CSi
3.25 LSD 25% locking - CSi and CSil
3.45 Open - Euro 3.0CS/CSA
3.45 LSD 25%...

• HB Chris
• Replies: 5
• Forum: FAQ - Frequently Asked Questions

• 

 

[Wes]

Mine has 3811 stamped into it and some yellow paint nearby. Guess could have been an 'S' at some point.
Is there another easy way to confirm if an LSD?

 

[HB Chris]

Most likely stamped, paint was not as common back then I think as they were used in e12 as well.

 

[eriknetherlands]

If it is an lsd, it'll clearly show you when you unscrewing the vent cover (4 m6 bolts i believe). Look inside, and compare to this: this is an lsd.
Non lsd do not have that big slotted screw.

Lsd's also have the ratio stamped on it.