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Subaru 4wd Issue

2005 Subaru Forrester X, 2.5L SOHC. ~69,000 miles.

Trouble brewing with the front axle and 4WD. When turning slow, either left or right and either forward or reverse (not so much in reverse though) there?s is a slight ?groaning? sound and the front tires feel as if they are jumping/skipping alittle bit every now and then. This behavior reminds me of my old 1989 Chevy S-10 when I had it in 4WD and made slow turns, though the Subaru is nowhere near as bad yet it shouldn?t do it at all. I?ve some idea what?s going on but need help to make sure I?m on the right track.


1. What is the problem - what is not working correctly?

2. Any chance this is something I could, or should, fix myself? I don?t own tools to pull or press parts with. (Over the years I worked on my 89 Chevy, fixing/replacing just about everything on it).

3. Any chance the front brakes could be at fault?

4. How much to have a shop fix it?

Thanks for your help and advice.


center or forward viscous coupling isn’t so much viscous anymore. have it serviced. If you do it soon enough, servicing (fluid replacement/cleaning) should take care of it. Check the owner’s manual to see how often it should be done.

Are all four tires match in size/wear/brand/model? If not replace them so they match.

Is this automatic or manual transmission? My guess is automatic.

Only the manual transmission AWD Subaru has a viscous coupling. It is a sealed unit and you do not change the fluid.

The automatic transmission AWD Subaru uses an electronic clutch pack which does not have its own fluid.

My best guess is that the present owner or a previous owner ran the car with mistmatched tires, thereby damaging the viscous coupler or clutch pack. The symptoms that were described are a perfect example of what happens when the Owner’s Manual warnings about mismatched tires are not heeded.

My 2004 Forester X, auto transmission, developed this problem at 59,000 miles. The excellent independent shop I use recommended a change of fluid in the transmission/transfer case. They said it might take up to two weeks to see the full benefit, but the improvement was dramatic when I picked up the car. According to them, this is not uncommon in Honda CUVs, and they have seen Hondas that needed as many as two additional changes to solve the problem.

Cost on my Sube was $28, when done during the 60,000 mile service.

thread bump