rear diff prob
 

hey guys my dad has a v reg subaru impreza 2.0 turbo and the rear diff ran dry on the motor way , i sent the diff off to a rebuilder who said there was nothing he could do and get one on flea bay ,he told me the raito was 3.54 so i found one and fitted it this weekend but there is some thing really wrong with it there are loud bangs and the car seems to be holding back like it is strugling to drive any i dears what is wrong as i am well lost ,is there any way to check the raito :deadhorse:

to check the ratio, you need to disconnect the prop shaft from the diff and pull out the two drive shafts. With some tipex, mark the prop flange and casing in one line. do the same with one of the driveshaft holes. you should find that you need to turn the propshaft flange roughly 3.5 times to get the driveshaft hole to turn once.
also, check your gearbox code and let us know here so we can confirm that it does require a 3.54 diff.

If it was the wrong diff for the car you wouldv broken it by now by driving it and there wouldv been a thudd and it would drive like normal but front wheels only. Its worth asking if the diff was in good working order when you bought it.

Talking about rear diff if you were to change gearbox to a sti v4 gearbox would you need to change the rear diff aswell .

check your gearbox codes and go from there, like I learnt never rely on the engine plate to tell you what transmission you have.

This is how I learnt http://subarugears.narod.ru/Index.htm

that's a useful link that:five:

ok i checked his old diff and that is defo a 3.54 the one i put on it i think was a 3.9 im going to pull it out again, so i can take the back off and check it .but at the moment it drives like the hand brake is on with the loud bang noise when you go over 25 mph , any ideas where i can pick up a 3.54 as ebay has a lot of 3.9 and 4.1 diffs

Probably time to get a matching diff and gearbox as can't imagine you've done it any good at all driving it with mismatched ratios.

Shane

hey guys just to up date i got hold of the right diff and the car is all good cheers for all your help