Dirty Transmission filter


#1

Does a dirty automatic transmission filter make for hard shifting between gears? I have a 1999 Toyota Camry. About 2 years ago I had the same problem and had the transmission flushed and filter replaced and it solved the problem. This time I just had the trans fluid replaced and the filter was not replaced. The problem still exists!


#2

It wouldn’t hurt to replace the filter again. It is hard to diagnose these problems without either driving the car or at least seeing the condition of the old fluid and/or filter. If your old fluid was really bad, then replenishment and replacement of the filter would be in order, at a shortened interval. You could also be only delaying the inevitable transmission repair. How many miles on the car?


#3

The car has about 175,000 miles. Can I replace the filter myself and reuse the fluid since it was changed not too long ago? Thanks for your input.


#4

If the trans pan has a drain plug, then yes it is possible and won’t hurt, especially if the fluid is the correct cherry red color and you use a very clean pan. For me, it is too messy if there is no drain plug and I defer to my trusted mechanic. In most cars, a drain only gets out about 50% or less of the fluid, but allows access to change the filter. There is no guarantee this will change anything, this time, though. I have yet to get 175K out of any of the auto trans cars I have driven, so the trans may be on its last legs, if my experience is indicative of anything. DIY for $50 or less to see if things change may be money well spent.


#5

I didn’t think Toyota had more than a metal screen. Changing fluid hardly ever fixes anything but maybe a piece of lint stuck in a valve. If you have a clogged filter, you have to have some serious problems.


#6

Good point. However, Advance Auto shows filer kits for both the 4 cyl and 6 cyl.


#7

Your transmission should still have a throttle valve cable. This sets the line pressure for the shifts depending on the throttle position. So you might have its adjustment looked at. If that isn’t the problem have the line pressure measured to see if it meets idle and stall specifications and if it tracks the throttle valve position as the cable is withdrawn. You could have a stuck throttle pressure valve or a stuck primary regulator valve causing the high line pressure. The previous flush might have cleaned out the debris that was causing the sticking giving you the reprive.

As mentioned by others, if the transmission is making enough debris to clog the filter and allow some to get into the valve body, there are other problems going on that may have to be addressed.

Hope that helps.