Rear differential trouble?

[laseron]

I've got a "97 Outback Limited with the winter package. I'm getting a "thunking" sound from the rear when iI turn in either direction. I've changed the oil and friction additive in the rear diff, but no change. I think the rear diff has a limited slip package, and if so, it's probably shot. I guess my next step is to replace it. Any ideas?

 

Thanks, Ron

[nipper]

OK here we go, my mantra .... ENGINE TRANNY YEAR MILEAGE:banghead:

that siad if it is an auto, put int the FWD fuse and see if it helps. If thee is no cahinge look at the ceneter carrier bearing and universal joints, as they make this noise too.

If ti all goes away with the FWD fuse, i would look at having the tranny flushed.

 

 

nipper

[idosubaru]

search the forum for "torque bind". that's what nipper is referring to about the FWD fuse, that's a way to test for it.

 

if it's while you're turning it may be torque bind, i have some other things in mind as possibilities but if it only does it while turning that rules out alot of these other possibilities.

 

do your tires all match? are any different sizes or haven't been rotated?

[Commuter]

A 97 auto is prone to clutch pack failure and torque bind as the years / miles rack up. Normally, I wouldn't describe torque bind as a "thunking".

 

No limited slip rear diff that I know of in these cars. (99% sure)

 

Check that you don't have a bad endlink or something as well. Could be that simple.

 

Commuter

[laseron]

Well, it looks like my assessment of the problem not only didn't hit the nail on the head, I wasn't even using a nail! Thanks all- I'll try the diagnostics you've suggested. I'm thinking that I'll probably have to replace the clutch pack-this has been going on for several months. I'll let you know what happens.

 

Ron

[laseron]

I tried the fuse in the FWD socket, and no more bind. Had the ATF replaced

at the local Subaru dealership (they don't recommend flushing the tranny)

and problem solved. Thanks everyone! This forum is great!

[idosubaru]

NICE! can't beat that. glad it worked out for you.

 

if they did a drain and refill then i'd have it done again as draining only gets a small amount of the old fluid out....maybe %50 at the most. i usually do 2 or 3 drain and refills on mine to get it all out. drain, refill, drive a little then repeat.

 

an aftermarket cooler is a great idea as well. they are $30 from the store and are far more effective than the stock radiator mounted lines...those aren't even true coolers in my oppinion.

 

trans are expensive, the effort now is worth it.

[Andyjo]

between tranny fluid changes, drive alittle, and crank the wheel all the way to one side and to a few circles, it'll get that grimmy tranny fluid mixed up real good

Also, to see if you have an LSD (Limited slip diff), jack up the rear end of the car, and turn one wheel, if the other one goes the same way you have a LSD, if not, you have an open diff. (I think... or did i say that backwards... someone correct me :-p )