There are lots of discussions on here about not putting LSD equipped cars on the brake rollers for an MOT and in fact the MOT manual does say don't do it. For the past 2 years my car has gone on the rollers so today at my MOT, I asked the tester why. He surprised me by saying that he hadn't realised that mine had an LSD as it hadn't behaved like one when he was turning the rear wheels during the checks of the rear. He said he usually spots them during that check. Because of the unusual behaviour, it wouldn't affect the brake test - seems the MOT instruction is because of the effect on the test rather than any likelihood of damage. He wondered if the diff behaves differently at different speeds and maybe the roller speed wasn't enough to activate it.
So the question is: what is it about an AP Suretrak that makes it behave differently from, say, a ZF?
Its definitely an AP diff as a)I have the original purchase docs for the car b) the diff is stamped with an AP part number and c)it does rather excellent donuts.
Yellow SL #32