does anyone know anything about the gearbox and diff etc on a impreza wrx? Just put another gearbox out of a version 4 sti into my version2 wrx now and then there is a large vibration like the wheels are falling off but are'nt could it be that the rear diff is the wrong ratio for the new box or doesn't it matter?

 

i've got the same problem on a 98 sti .its had a new gearbox and i just fitted new diff but vibration is still there at around 3000rpm and it get worse the hotter the car gets.
its doing my head in

 

Yes, yes - I have -exactly- the same problem.

Ive had it up on a hoist, and saw some decent vibration in the back part of the shaft, so we replaced the shaft, and im about to get a new diff.

What gearbox fluid are you guys using? I read on a US forum recently (nasioc i think) that the centre diff can cause this if its got stuck plates?

Im also concerned that I have the wrong rear diff, im going to see if i can get my car analysed on a dynapack for torque split.

You lads get any progress?

g.