anyone know the insides of an 80's bmw lsd

[Kawasicki]

Hello all

I just sold a BMW lsd on ebay. The buyer has called to let me know that the diff is just an open diff and unsurprisingly wants his money back. Now I know the diff came off a 535i sport, it also had a seriously rusty metal tag that after 20 minutes of cleaning away rust exposed a "S" part No., which would normally signify a lsd. Before I handed money over for the diff I also checked that both output shafts turned in the same direction when the input shaft was turned.

So my question is, does anyone know whether it is possible to determine whether a diff is an limited slip or open design just by removing the rear cover and having a look?

thanks,

Shane

[Talkwrench]

You can definitely tell by removing the rear cover.
Open diffs have open gears that can clearly be seen.
LSD's have an enclosed LSD assembly, only showing the crown gear. They look quite different.
An open diff will sometimes turn both output shafts the same way if the drag on each is equal (just as it would if the car were being driven). The best way to tell is by trying to turn the output shafts in opposite directions. This will prove nearly impossible by hand.

[SteveSlowboy]

Yes, it should be easy to see the difference once you've removed the end cover;

a plain open diff - you'll be able to see the planet gearrs within the centre framework that supports the crown wheel.

A LSD will have a fairly solid looking cylinder with the crownwheel bolted to it in line with the output hubs and with some small openings (I think) prob around 20mm diameter or smaller.

Sorry not the best description but hope it helps.
Steve

[Kawasicki]

Gentlemen,

thank you so much. Comments noted and appreciated. Looks like I sold an open diff as an lsd, duh! So it's money back time!

shane