when swapping from 4.44 to 3.545 front diff, is it just the crownwheel thats different, or the little pinion gear too?

im thinking both? which would mean swapping the gearshaft too

any ideas?

thanks, ian.

p.s. dont want to swap the whole box, as its v.low milage and close ratios....which i want to keep
and yes, i know to swap the rear diff too

 

I think you'll find that the 3.54 is only listed for the UK rear.

UK cars, whilst listed as 3.9, actually have a 3.54 rear crown wheel/pinion, because the final drive is actually 1.1:1, not 1:1 like the jap cars.

So, the lowest you can put in the front, is 3.9, and then you'd have to match the rear.

Front cw/p's are pretty cheap (relative) under £200 new, but the backs are blo*dy expensive. I think my rear 3.9 cost circa £450 + vat.

If you use second hand parts, be VERY carefull. You won't be able to tell how worn they are, until you fit, and check the clearances.

Also, this isn't really a "DIY" job, the cw/p's need shimming.

Mark.

 

hi mate, thanks for the reply

what i should have mentioned is that i have both the front and rear diffs in the shed. they are from my legacy (uk turbo)and have done 59000miles and mint.
i swapped the box and diffs (to STi RA ones) when i stripped 2nd gear as i couldnt find a legacy box.
i want to keep the close ratios, but the very low (4500 @ 85mph !!) gearing is doing my head in now. only does 125/130 @ 7000rpm redline now too

cheers, ian.

 

crown wheel and pinions come as a set and define the final drive ratio.

mark is righjt in that the UK impreza turbo has a rear final drive of 3.54 in the diff housing then a 1.1:1 transfer box between the diff and the gearbox.

I have no idea why they do this, but overall it gives a final drive of 3.9

the crown wheel has 39 teeth on the front, and the pinion 10 so yes they are both required.

I still wouldnt want to do the job myself though, but then I never do.

 

thanks for the reply adam

ill have to swap the gears over to the other shaft then....bugger!

thanks again, ian.