My 83 US has an LSD.

Both my friend heathers and my friend tims both have it too(85 US and 83 US respectively).

 

All 928's including GT from '90 model year forward have PSD. All up to '89 had 40% ZF as optional extra except '88-89 CS, '88 SE and '89 GT. On those three models it was standard.

About the noise from LSD diff. If gearbox oil is wrong type diff can make grinding type of noise. Friction plates do not like additives in some oils. Also diff casing was changed early eighties ('83 ?) to allow oil flow more freely. Earlier version restricted flow and caused noise when turning.

 

Say what's the best type of gear oil to use in a 928 LSD?

I've never changed mine, i'm sure it's due.

 

LSD requires special friction modifier additive. There is some talk in archives concerning Redline 75W-90 oils. They should work ok. There are two different types of it, regular and NS (No Slip). Mixing those two has given good compromise between syncro life and LSD noise IIRR. Check the archives, been discussed extensively.

 

Mine is an auto, no syncro issues for me.

Thanx, will do.

 

The 87S4 I was looking at recently had LSD. It was listed on the photocopied window sticker as a
$722 option. When I do ad a later model to the stable, it will have LSD. My 79 has it.

 

good timing! just discovered I've got a major traction issue due to no LSD.... anybody got one FS??