HELP! rear end shaking

zeevann said:

let me explain a little better, the only time it does it is when backing up turning or going forward turning, but i have to be going slow, its like they are locking up and there a clunk and the whole axle rattles. my brakes aren't locking up tho. we were thinking possibly a u joint? checking later tonight. But another idea floating around is that the gears chipped a tooth, but i figure it would do it all the time(my friends like to think the worst)

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trinity_gt said:

It's your differential, specifically, the "traction lok" limited slip portion of the differential. The clutches are chattering, releasing and grabbing as the diff tries to do its thing with the inner and outer wheels turning at different rates as the car turns.

If you've had the oil changed recently, this can happen if no friction modifier additive was added to the new fluid. If the oil is old, replace it with a 75W140 synth and add a bottle of friction modifier (get this at a Ford parts counter...)

i'm with this guy except for one thing i wouldnt go to ford to get it too expensive they sell a limited slip additive at your local parts store i.e. autozone napa advance etc.

but it sounds to me like a limited slip deal but if it IS bad then why not use this as a chance to upgrade your rear??

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