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clutch slippage


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Guest jcdenton

Hello, I am normally on the 80's subarus part, but my mom's 98 2.5RS has a problem with clutch slippage.

the dealership says that it isn't slipping, but I have seen (heard and felt) it slip at least a dozen times now.

what is causing this problem and why are the dealer's mechanics missing it?

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Guest subaruownercgy

To confirm that your clutch is actually slipping do this:

 

Drive at 25 MPH on flat ground and put it in 5th gear. The engine RPM's should be at about 1200-1500 RPM.

 

Now floor the accelerator.

 

If the RPM's rise the clutch is slipping, if the engine labours to increase speed the clutch is probably ok.

 

Try this trick again at 30 and 35 MPH as well, since engine torque increases significantlay when the RPM's near or exceed 2,000 RPM.

 

You can also drive at 40MPH up a hill in fifth and floor the accelerator to detect slip

 

If the dealer did not do this simple test, they should loose their mechanic's license.

 

If it is slipping, confirm that you have "free play". Normal clutch pedal travel is about 5 inches or so. For the first inch of travel the release fork will not just begin to push the release bearing into the clutch. The next two inches of travel will progressively release the clutch, and the bottom two inches will have the clutch fully released.

 

If there is insufficient free play, the clutch my be partially disengaged all the time leading to slippage.

 

You may need to adjust the free play which is quite easy to do.

 

Another cause may be oil contamination on the clutch disk, which is somewhat rare, but not unheard of in a Subaru. Changing the rear crankshaft oil seal during a clutch change is fairly common practice. Usually any leaked oil is prevented from getting to the clutch disk by the flywheel, but you never know...

 

By age (5+ years) you may be due for a new clutch, but what is your mileage and percentage of highway driving?

 

60,000 miles on a Subaru clutch with 30% city driving is considered good.

 

Does your car have a "hill holder"? It may also need adjustment. Two adjustments for the hill holder, one for brake release point (as the clutch is release, where does the brake release) and the other for activation incline (the angle of the road at which the hill holder activates). For the release point it is a simple cable adjustment, for the angle shims are added or removed.

 

Subaru has released several TSB's for defective clutches, mainly for rough engagement (judder), but none that I am aware of for slippage. Also I beleive these TSB's were limited to 99 and newer models with the EJ25 SOHC engine, not your DOHC model.

 

AWD vehicles are much harder on clutches than two wheel drive models.

 

BTW: I got better than 240,000 miles on my 1993 Legacy's clutch before it started to slip. I did add shims to my hill holder to set the activation angle at about 8 degrees (steep) and backed off the brake release cable so the brakes would start to release when the clutch came about 1 inch up from the floor.

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