LT Texan

No, I'm not going to do a burnout and measure the rubber laid down.

But with the transmission in gear, there is a lot of resistance in turning one axle.

Never thought about it. Just noticed it in changing the rear wheel bearings.

namasgt

lift the rear up, put it in neutral, turn one wheel and the other should turn in the same direction. If it turns in the opposite direction then it does not have LSD.

ammonman

Check the number stamped on the transmission case. If you have the number "12" preceding the transmission number it was built with a 40% locking differential.

Mike

LT Texan

that makes sense.

I can check that too

Thanks

Jadz928

Doesn't apply to the early cars. I'm not sure what year they started stamping the 11 or 12. Anyone know?

Ducman82

also some one could have swapped one in..

Vilhuer

Should be since '78 MY and its just extra 12 added in. There is always 11 in the number which means transmission for 8 cylinder engine and 5sp manual.

Jadz928

So far this has not been my experience. But is is possible that they were not originally fitted with LSD. Will keep looking.

ammonman

It would be interesting if the "12" code was not applied until later. I was going by what is in the "'78-'80 Models, Dimensions, and Tolerances" booklet. But as we have all experienced with Porsche documentation, it could be correct only for certain years and they just neglected to mention it in the spec book.

Mike

Tony

I would assume this holds true for a transmission not mounted in the car?

you can just turn the axles stubs In the same manner?

Dave928S

Yes .. it gives a clearer indication, as you don't have the possible interference and confusing influence of dragging brakes/hand brake or wheel bearings. The proviso is that the LSD still has functional friction plates ... if not it will behave like a standard diff.

The best way to be certain is to look at the spool through the fill plug hole or take the back cover off. This post shows the difference ... https://rennlist.com/forums/10557488-post7.html

OTR18WHEELER

then you dont need it!

AirtekHVAC

^^^^^^^ hahaha...good one,,,!

LT Texan

And measure the rubber laid down, silly.