JeremyMary

Hello,

I apologize if I'm breaking any rules right off the bat. I'm somewhat new to these types of forums.

My wife and I just purchased a 2002 Subaru Forester S with 30,000 miles on it.

While cruising through the ice and snow I noticed a "noise" that I don't know if I should be concerned about.

When given a little gas, it sounds like the rear tires begin to spin a little, then there is a slight "clunk" with the car then surging forward.

I'm assuming this is the rear wheels kicking in with more power and traction to stop the spinning. The clunk would be the differential(?) engaging?

I'm just guessing here...thanks for your time.

Jeremy

mda2000

If you have a limited-slip rear differential (which I imagine you would) both rear wheels are always engaged. There are clutches that allow each wheel to rotate at different speeds (such as going around a curve). If a limited-slip additive is not added when new gear oil is added (such as after a complete draining, not a top-up) then the clutches will not slip, they will stay locked until the pressure is too great, then they will make a loud "clunk". This may be your problem. If the previous owner had the rear end serviced the garage most likely did not add the necessary additive. They say the new gear oil doesn't need an additive, they are wrong. Contact your nearest Subaru dealer for the additive. Hope this helps

Bartender

Good morning -
We own a 2001 Subie Forester, and it definitely does have a locking dif. We're experiencing some snowfall here in Western Washington, and we've heard the "Clunk" several times. I was alarmed the first few times, then figured that's just what it does. But now it appears that is not the case. Is this oil additive available anywhere, or should I go to Subie for the "special" oil?
Thanks!

mda2000

You had better go to Subaru for the additive. I have never seen it in the stores. It will probably be a little pricey, but it is worth it to keep from replacing a rear end. Hope this helps.

erhayes

My 2000 Forester doen't have a "locking" differental but, a "limited slip differental". It only requires a 75/90 GL5 rated gear oil. Ed

Bartender

Hi, erhayes -
I'm sorry, I meant "limited slip" when I wrote "locking". Hope I didn't cause any confusion for anyone.
We've only got 26 thousand on our 2001 S, but I think we'll just change all the fluids from front to back and see what happens. The snow didn't last long, as usual around here. May not have another chance to listen for the clunk this winter so better just do it.