hi all ive recently swopped my gear box after it fooked its self.
ive got a my99 uk turbo and i used a jdm my98 wrx box, but its nothing like my uk box.
can anyone tell me the difference, im running out of poke @ 120 and the uk used to pull to 150 easy

 

Ooops, recipe for looming disaster ahead. You've fitted a gearbox with different ratios, drop gears and front diff final drive ratio to the one you took out (old weaker 752 casing too by the sound of it).

As you've noticed this has shortened your gearing markedly. What's worse is that if you didn't change to the matching rear diff at the same time, you've created a mismatch between the front and rear final drives that will soon, if it hasn't already, damage the centre diff and leave you with another "fooked" box.

Best take it out ASAP and find a proper UK box to replace it with. You could try finding a matching rear diff, but that'll still leave you with ratios that are shorter than ideal, both for your engine's powerband, and its cruise fuel economy.

 

ive changed the diff with the box that i bought and it had been rebuilt a few thousand before a got it, but you would recomend that i find a uk box or get the old one rebuilt.

 

If you've got the correct rear diff, then that at least solves the centre diff destruction issue so at least you can sit back and take a view on it.

As for recommendations, you know better than us what was wrong with your old box so you're in a better position to decide between getting it rebuilt or picking up a recon/secondhand UK replacement. Why not give someone like APi a ring and describe what was wrong with it to them - they should be able to give you ballpark prices for both routes.

 

the center diff gave out on the old box but ive just had my car remapped by jgm on the new gearbox so if i was to change back should i have my motor remapped again.
ive been qouted 700 to rebuild my old box