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2001 Forester Automatic transmission

I have a 2001 Subaru Forester. The transmision filter was damaged by an oil change place causing the fluid to run low. A short time later the transmission (automatic) needed to be replaced. The shop said it was the forward clutch disc flaking coming apart. Can one cause the other? The car had around 100,000 miles on it and it seems a Subaru should get more miles than that on a transmission.

Whether the fluid ran low enough to drop the line pressure or the misinstallation of the transmission filter allowed air to entrain and lower the line pressure, the low line pressure allowed the forward clutch to slip. This would have overheated the friction material causing it to deteriorate. Thus its inability to hold together and adhere to the clutch disc. Did the shop indicate any signs of slipping and overheating of the forward clutch discs and plates, i.e. blueing or warping?

Post back if we can help you further.

They really did not say and unfortunately I did not ask. All that is indicated is the forward clutch disc flaking coming apart. The oil change people tried to remove the transmission filter (looks that way) and crushed it putting a small hole in it. The transmission people are not being that helpful, I just had it rebuilt for a second time and then 4 days later it failed catching on fire. Luckily I was able to put it out before it got out of hand. Lets just say they have not been that helpful.

So which AAMCO did you take it to?

Just an idea. If the rebuilt transmission failed in 4 days and caught fire, check out the oil flow through the heat exchanger in the radiator. If the previous transmission, shed debris that might have made it to the heat exchanger causing it to clog. There is a back flushing procedure for the heat exchanger but if it really is badly clogged the bottom tank or the entire radiator may need to be replaced.

Good luck on this.

I have a few questions.
Are you saying the oil change facility damaged the filter and you drove off with it leaking?
If so, were there any shifting symptoms?
If the transaxle had recently been rebuilt then why was the oil change facility messsing with the transaxle to begin with?

A transaxle that is low on fluid and exhibiting shifting problems is actually destroying itself so the flaking could very well be caused by that.

Transaxle problems, especially with automatics, are not that rare with Subaru although 2 rebuilds already could point to a leaking trans fluid cooler as mentioned or poor rebuilds.

Another possible cause of premature transaxle failure is internal oil leakage from the final drive. The final drive uses hypoid oil and some Subarus have been prone to internal oil leakage in which the hypoid oil from the final drive mixes with the ATF. This dilutes the ATF and can kill a transaxle. It’s also near impossible to detect unless one notices the final drive oil level is down.

If the transaxle was rebuilt properly all of the final drive seals should have been replaced as part of the rebuild.

Hope that helps.

Absolutely!! An automatic transmission which runs low on fluid will cause slipping of the friction materials and the forward clutch will be the first to go. You have a good case.

Now, if this thing got hot enough to catch fire, most likely either the forward frictions or the TCC friction came apart and caused a drop in the cooler flow. If the cooler flow is restricted, you must replace the radiator. This has nothing to do with line pressure, fluid leaked out for whatever reason, air got in, frictions slipped and superheated, transmission gone. In my experience, you can not get the trash out of the cooler assy enough to bring back sufficient flow. Another thing, dont rebuild that unit again, especially if it got that hot. You’re asking for trouble.
Buy another unit.