gearbox/ diff problem

[m7key]

hey all
when im driving i get this big clunk i lose power to the front wheels. within a second its fine again, it doing this at all different speeds and gears. i though it was my cv joints because they were on the way out but i got them replaced and its still doing it. and its getting worse. im not driving it atm untill i get it fixed. the mechanic said it might be either the diff or the gearbox but because its happening in all gears i think it probably the diff... has this happened to anyone before? and are there possible fixs other than replacing the hole gearbox and diff? any advice?

thanks

[bennjamin]

been thrashing the car? Any hard launches ? Any reverse-to-1st roll back burnouts etc ? I ask because I stripped down a gearbox recently where the owner did this alot and there were chunks of metal broken off teeth in the differential and a similar clunk as the diff struggles to properly bias the torque to each wheel

[m7key]

well iv looked after it... i dont really drive it hard much and i dont really do hard lauches. but thats not to say i have not done them. but the car has over 200k on it. and im the 4th owner so i dont know what they have been doing to it. it first happened when i was accelerating out of my street, but i was not really thrashing it

[bennjamin]

try this

open your engine bay - leave the car in neutral and let it idle. Make sure its warmed up - now grab the throttle cable with your finger and rev it ( or get a mate to rev it from the cabin). Does the engine lurch forward and backward much ?

[m7key]

um tired that... it moved forward and back. but no more than usual

[bennjamin]

well thats counting out a broken rear engine mount.
Sure there arent any chunks of metal missing off the rear mount etc ( that connects to the diff housing)

[m7key]

yeah i check all the engine mounts... they all look fine. must be something to do with diff then. would it be cheaper to get someone to rebuild it? or just buy a new gearbox and diff assembly and get them to put that in?

[DC2-PWR]

drain gearbox oil and see if any metal comes out
i had the same problem with my old dc2 VTiR gearbox, long story but it had no oil in the gearbox.
after ahwile i used some expoxy crap to cover the hole of the gearbox and filled it up with oil
then suddenly oil started pouring out the hole one day and i drove home with barley any oil
then it started cluncking/knocking. gears were hard to change too

[m7key]

dont think its that. gears changes are fine. plus when i got new cv shafts the mechanic changed the gearbox oil

[m7key]

ok im putting a new gearbox in. been quoted 550 for a gsi gearbox. just a quick question would a gearbox from a B18A fit as well? with out any modification?