Our indy has developed a strange 'shift' at the rear when you back off the throttle.

Basically accelerate, then back off and it feels like the back end lifts and the weight shifts to the drivers side - it makes for quite an un-nerving drive. Kinda like if the rear passenger side brake was binding (which it isnt).

We've had a check for play and binding brakes but cant find anything.

Could it be geometry related? or perhaps transmission related? Diff?

Its kinda hard to tell if its the back thats causing it or the front. you can sort of see the body 'pitch' itself toward the kerb at the front, its odd.....

Running gear is duratec with sierra transmission (type 9 etc).

I'd thoroughly check all the suspension bushes for wear and the wishbones and brackets for cracks/broken welds.

You could try chocking the front wheels and then loading up the rear wheels alternately in 1st and reverse (i.e. slipping the clutch) and get someone to check if anything is moving at the rear.

[Edited on 1/5/10 by MikeRJ]

My GTM did this with weignt transfer in hard corners - turned out to be an upper balljoint providing occasional rear steer!


It was hard to replicate without putting the car in a hedge

A friend of mine had a similar problem, it turned out to be his diff that was at fault . It was a chain driven lsd but i would imagine the same could happen with conventional diff.... might be worth swapping it over if you can borrow one of someone.

I had this in my indy for a while, It turned out to be the upper rear wishbone chassis to bolts that had worked a little loose. That would be my first check.
hth.
john

I'd check all the bushes at the rear and if they check out okay I'd personally suspect the diff- perhaps one side has some backlash issues. But to me the workings of the diff are akin to black magic so don't take my word for it