I have been looking for a IRS with Power Lock to replace the open diff on my 1975 C. I think I’ve found one for sale but I’m a bit complexed. I haven’t seen it yet but talked to the seller over the phone. I asked the seller to do the hub turning test. “Turn one of the hubs the opposite hub turns in the same rotation PL diff, opposite rotation open diff”.
My question, the seller turned a hub and nothing happened with the opposite hub it didn’t turn at all, is this normal
The seller says its out of a 1981 S3
If there is sufficient internal resistance on the opposite half shaft then its an open diff, I would have expected to see a bit of movement though.
Hi Robin, I would have expected a bit of movement to but nothing. Maybe give this one a miss.
Either it turns in the same direction or in the opposite, if it doesn’t turn it’s open and the driveshaft is rotating because the rotation has to go somewhere. In neutral the driveshaft will turn if the other hub is tighter than the driveshaft. It’s probably not PL but you can have him try again with the transmission in park.
Ask him to check if there is a tag with PL stamped on it, similar to the one with the c\w and pinion teeth numbers. Attached to the rear cover plate on the diff. Either way, doesn’t sound like a PL.
Deano, the only S3 that has a PL diff would ne a V12
Thanks for your reply’s guys. The IRS is out of the car so maybe ask him to clamp the drive shaft hub then turn wheel hub There is no P/L tag on it and it came out of a S3 with a 4.2 in it. So very much looking like an open diff. I’ll get back to you guys with the result. Thanks again, cheers Deano
He can just hold it with his hand. It should still be easy to turn unless something on the other output side is locked up.
Some S3 came with PL diffs but rare.
I asked the seller to hold the driveshaft hub while turning the wheel hub and the opposite wheel hub turned in the opposite direction. So it’s an open diff.
Thanks for all your comments. Cheers Deano
Happy to help. Cheers