Subaru AT very slow to engage into Drive

Maintenance/Repairs
1

Hi Tom & Ray,



I love your show and often try to see if my dx is the same as yours.

We bought a used 1999 Subaru Forrester S w/ AT 2.5 ltr for our son. We have driven it about 6k miles and it currently has 91k on the odometer. The problem is when selecting “D” of 1,2,3 it often (but not always) hesitates to engage 10 - 45 seconds). I can not determine any conditions that seem to make this more or less predicable, ie, cold, hot, first starting, etc. I did not flush the fluid, but I did change it as well as the filter. No noticeable improvement. Once it engages, the transmission works fine. I looked for others with this problem on the internet and found many similar complaints; however, no solutions other than a rebuilt or replacement of the transmission.

I know you guys love Subarus so I thought you may be my best source for a clue or solution.

Thanks!! Frank

2

Do you get a delayed engagement when shifting to Reverse first thing?

One diagnostic test would be to monitor the line pressure when this happens. If you could get a gauge hooked in and placed where it could be observed when this happens, you could see if there is pressure being developed. If there is no pressure when this happens, it could be because the pump has lost prime or is air locked or it could be because one of the piston lip seals is lazy and leaking oil until it pushes out and seals. The leaking lip seal would probably be in the Forward clutch piston. However, with the mileage and age, this is unlikely.

If you get this problem solved, post back what was found as to the cause. You can educate all of us.

3

This transmission has issues with converter drainback. To fix what needs to be fixed on this will require removal and disassembly of the transmission. I would let a shop look at it first to confirm. I see quite a few of these.

transman

4

Thanks for the quick response. Engagement into reserve has no delay, Just the forward gears. Not sure which “line” you are referring to for a pressure check.

F

5

Thanks for the quick response. a few more questions:

  1. Just to clarify, would replacing the torque converter fix the problem, or would there need to be disassembly of the transmission as well?
  2. If I remove the transmission, would repair or buying a rebuilt unit be more cost effective?
  3. If you have experience several of these, was there a year the Subaru corrected the problem?

Thanks! F

6

Hi There is a 1/4 inch pipe plug on the side of the transmission that connects to the pump output passage. I am not exactly sure where it is on a Subaru. This is the pressure that is used to engage the various clutchs as the valve body spools switch. By monitoring the ‘line pressure’ of the transmission you can discern if the pump can hold the pressure up when a clutch is engaged. It is a way of looking into the transmission to troubleshoot a problem.

7

You might try a product called Trans-X to see if that will clear the trouble. Others have solved this kind of trouble using it. Sometimes a solenoid valve sticks.