Swapping a Swap – An Impreza r160 Rear Differential

Tempting fate and with full disregard to the space time continuum, we swap an older JDM WRX transmission and rear differential into a 97 Impreza L. The transmission that we removed? A newer WRX transmission. The day was long, allergies did their best to discourage us, however we pulled through.

The swap itself was pretty straight forward, as with most Subaru stuff, mechanically everything pretty much fit. So as not to upset the ECU, we simply swapped in the original 2.2L sensors. At the end of the day the car is much quicker with the much better matched lower gears. I may add more to this later depending on the comments, for now though enjoy the  pictures.

Some more information from Darin and this post on Flat4:

car ran great on the way home, other than the broken speedo cable not allowing me to revv over 4k…
even with 4.44 final drive, im only about 250 rpm higher at around 70 in 5th and i can feel the car accelerate in 5th gear…

Its still an r160 diff. not sure what you mean by diff covers.
the lsds’ are different, on the usdm wrx diff(on left) the lsd assembly is open, ie you can see the spider gears, while on the jdm suretrac the lsd assembly is sealed. the biggest difference between the two is on the us is a 3.90 w/3.54 viscous lsd rear compared to a 4.44 w/4.44 apsuretrac torsen style diff. the gear ratios in the jdm trans are exactly the same as what i have in my wrx, except to final drive is 4.44.