Problem when turning... diffrrential?

[Airborneguy]

I have an interesting problem, I think.

2003 manual N/A, 158k.

I say this because it only manifests aftwr highway driving for 20+ miles. If I haven’t driven for awhile on the highway, this problem does not occur and the car drives and turns like it’s brand new.

After 20+ miles, when I exit the highway and start making turns - especially tight ones - the wheel I am turning towards makes a loud clunking sound (audible outside of the car as well) and skips a little.

We replaced the right front axle and transmission fluid when this started happening. That didn’t fix it.

Does this sound like something obvious to you Subaru experts? My mechanic is my step-father, so while my labor is free, I obviously want to save him as much trouble as possible.

Thank you!

My mechanic is stumped because of the fact that it only happens after highway driving. He thinks it may be a brake caliper heating up too much and seizing a little, but I disagree because even when experiencing the problem, I don’t feel a thing unless I am turning.

[HaHaBajAlcyone]

Maybe a centre diff problem....?

[anarchy1024]

My first guess is a wheel bearing, followed by CV joint... Although, if it was the CV joint, it should happen all of the time, I'd think. The front diff is open, so there aren't any LSD-specific things to bind. Could be the center diff, since that is an LSD (limited-slip differential), and during tight turns, there a much greater difference between the distance that the rear wheels travel vs front wheels.

I'm guessing wheel bearing first, because of the highway distance (resulting in temperature) component of the symptoms. That, and I'm pretty sure they cost less than a center diff (ignoring labour cost, assuming he has the tools to do it). And while doing that, you can examine the CV joints to see if they're damaged, since the axles would need to be removed, anyway.

[kamesama980]

Wheel bearings are unlikely to cause the hopping/skipping/binding you feel on tight turns. I've changed enough in my time in a shop to know better than to say never but that's much more likely to be a a diff problem. I could see it being an axle though more than a bearing as the rollers actually ride a different part of the cup when you turn.

Subie center diffs viscous units are known to show that exact symptom. my turbo does it but only after a highway run of 75+. 60-65 all day won't do it but couple miles at 80 and it binds up directly proportional to steering input. have a used replacement viscous unit to go in one of these days when I get some other projects out of the garage.

[Airborneguy]

I left out that we changed the axle when it first started as the boot was ripped bad. That didn’t solve the issue so that’s why I’m leaning towards differential now.

[walfredo]

What axle did you replace the bad one with. If it was a remanufactured axle - those are junk and are commonly bad from the get-go. I made the mistake of trying them and ended up getting 3 bad ones in a row until I just said forget it and got an OEM used axle from the junkyard.

I will never ever go with a remanufactured axle. New aftermarket is ok, but preference is to either rebuild the oem one, if possible, or go with OEM used.

That said, I have never experienced a bad diff but it could very likely be the issue as well. It makes sense right? When turning, your inner and outer wheels are rotating at different speeds and having a bad differential would likely show symptoms when under those conditions.

[Airborneguy]

Replacement was an OEM rebuild.

We’ll know soon because after a month of back and forth I should have the new center diff and gaskets I’ll need to remove and replace the exhaust within a few days. One of my part-time employees is a salesperson as the local Subaru dealer. She got me the parts at cost. My step-father and I will install them hopefully next week sometime.

For what it’s worth, I drove over 200 miles each way for a trip last weekend and experienced nothing more than the usual skipping I’ve become used to now.

[lpcard]

Center diff.

Ask me how I know...