If I had a 4.11 in the front diff with a 4.444 rear, how obvious would it be during normal driving? Just had a new tranny put on my 04 Forester XT Auto last week, trying to eliminate this as my problem. Wouldn't I be getting lots of binding and bucking? If I'm understanding it correctly, the rear driveshaft would be spinning faster than the front one right?

 

The XT's have the Active AWD(90F/10R controlled by a transfer clutch) but on "power brake" launches to 3,000rpms with my high stall torque converter, the rears just spin and spin, even fishtailed..Even on a semi-normal takeoff from a redlight on a wet road, I fishtailed.

 

Fluids in both diffs were drained/refilled last week along with new ATF put in when the tranny was swapped.

 

Am I just being paranoid? Discuss.

That will probably cause problems.

I know with the old school stuff, if you have a 3.7 trans and use a 3.9 rear diff (and vice verse) it creates all kinds of binding.

I would think I would see binding too, but everything drives fine...

 

Just can't understand why I would be fishtailing, as I'm front wheel biased..

 

I put the FWD fuse in, not sure if its gonna help though.

I replaced the tranny in my old impreza once and we accidently put a 3.9 tranny in and it had a 4.11 rearend and it felt really weird but didn't bind much just drove and steered funny so that could be it!

:dead::dead::dead::dead:

tranny will be dead

You wont kill the tranny, but you will kill the AWD unit really quickly. Put the FWD fuse on the holder (if you have one) and drive it that way untill you get aproper rear end. Also you may find really hairy handling in the rain or the snow when the AWD is trying to keep the car stable.

 

nipper

 

Would it be easier to swap the front diff? I still have my old tranny (with 4.444) to match the 4.444 rear end..If it does have a 4.11 front, I would have to find a used rear diff.

Are you kidding?

I can swap out a rear diff in 1/2hr (if I dont drop it on my face:rolleyes:)

A tranny swap will take a couple hours, at the most.

What I'm asking is, can just the front diff be removed and replaced without dropping the transmission?

What I'm asking is, can just the front diff be removed and replaced without dropping the transmission?

Not likely.

No, the front diff is between the engine and tranny, generally considered part of the tranny. Rear diff swap is easy.

there's a procedure for checking to see if front and rear diffs match.

 

BE VERY CAREFUL.

put one side of the car on jack stands. (2 wheels off the ground)

unplug the wire harness to the trans. (locks the wheels in 4WD)

start the car and put it in neutral. (wheels should spin freely)

mark the bottom of the front and rear wheels with tape or chalk.

turn either the front or rear wheels by hand several turns.

the tape mark should end up in the same position on both wheels.

if they don't, the differentials do not match.

 

don't forget to plug in the wiring harness after you put the car back on the ground.

there's a procedure for checking to see if front and rear diffs match.

 

BE VERY CAREFUL.

put one side of the car on jack stands. (2 wheels off the ground)

unplug the wire harness to the trans. (locks the wheels in 4WD)

start the car and put it in neutral. (wheels should spin freely)

mark the bottom of the front and rear wheels with tape or chalk.

turn either the front or rear wheels by hand several turns.

the tape mark should end up in the same position on both wheels.

if they don't, the differentials do not match.

 

don't forget to plug in the wiring harness after you put the car back on the ground.

 

thanks for the info...gonna have the shop that did the tranny swap look at it on Tuesday..I'll post my findings shortly after.