looking for an easy way to keep the stock unit in the back with better gears after the t5 swap. it has 2.73's now, it is a non-posi and its really lame lol. can you just swap in a 3.73 posi ring and pinion? i don't want a new rear end, i'm keeping the stock rims and i don't want them to stick out in the back.

 

You'll need a 3 series carrier (posi). You'll also need to set up the gears for proper wear pattern which isn't something a typical backyard mechanic can do properly.

Buy the gears you want, buy the proper posi, buy a bearing installation kit. Have a driveline shop do the swap.

 

sounds like it'd be easy to just buy a 3.08 posi and throw it in there lol. what rpm does a 3.73 with a t5 turn at 60 anyways?

 

youll be happy with the 3 73s with the t-5......

 

Just had some friends help me change out a 3.23 for a 3.73. Now it's time to start moving to the front of the car

 

what rpm does your car turn at highway speeds???

reason i ask is because this car see's a lot of highway miles with commuting and trips (going to massachusetts next year and he goes to cali every other year) and needs to get gas mileage. last thing you want is to be turning 3k at 60.

 

Changing gears requires setting the pinion depth, bearing preload and backlash. You must know how to read the contact pattern so that you will know what adjustments need to be made to the pinion depth. If you are going from a 2 series gear to a 3 series then you also must change the differential. If you want a posi then you are going to have to change the differential anyway.

 

About 2250 at an indicated 70mph. My speedometer is still a little off, over a measured 5 miles, it gains a tenth or so. Apparently I chose the wrong driven gear, I'm off I think by one tooth. I still get about 20-22mpg on the highway with the mostly stock TBI motor.