Things they don't tell you about your AWD Subaru

S · 2009-06-09T18:44:38+00:00

Hi All!Two words: Torque BindInside of your AWD transmission is a clutch pack which allows the reardrive to "slip" a bit during tight turns and such, thus eliminatingthe klunk-klunk-klunk noise/sensation (torque bind) you would getotherwise.Fine and dandy, but what do you do when this clutch begins to wearout?Sadly, as far as I can determine, you buy a new transmission; $3,500for a manual box, and (gasp) $5,500 for the automatic version.I replaced the manual transmission in my wife's '02 Forry (140K miles)last weekend for this very reason. Fortunately, I was able to locate areasonably low milage specimen at a local salvage yard, but whathappens a year or two down the road when _all_ of these cars haveaccumulated enough milage for the AWD clutch to be questionable? Gonnabe real tough to find a good used one, I can guarantee that!The next time I have a spare "round-tuit", I plan to pull the badtranny apart to see how difficult it is to extract the AWD clutch, andalso to see if there are repair/refurbish options available thru amachine shop. I will post my findings when I do, but meanwhile, I mustsay that this makes it unlikely that I will purchase another AWDSubaru. (And this from a looooong time Subaru advocate.)My old 4X4 GL wagon looks better by the day :-)Any comments on this more than welcome!ByeBye! S.Steve Jernigan KG0MBLaboratory ManagerMicroelectronics ResearchUniversity of Colorado(719) 262-3101

Jun 09, 2009 21 Replies

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XR650L_Dave 17 years ago

Just remember to rotate 'em and make sure the tread depth is the same on all 4.

Dave

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Yousuf Khan 17 years ago

Although what you described is possible, it's not possible for a manual transmissioned Subaru. The manual transmission version of Subaru's AWD doesn't use a clutch pack, it uses a viscous coupling system. The clutch pack was used on the lower-end automatic transmissions fitted to

4-cylinder engines. The viscous coupling becomes less viscous with heating, thus harder to move through; the speed differences between the front and rear drive shafts cause the fluid to heat up and become firmer.

A possible way this could be a problem is that if the front and rear tires have worn away at different rates and now have different diameters. This might look like torque bind, but it is easily remedied with new tires bought for all four wheels at the same time.

Yousuf Khan

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