engaging D in auto tranny takes a long time

[redphan]

I realize this is an oil forum, but I am posting here just in case my problem is oil related.....

I have a Subaru Legacy 2.4l. About 1000 miles earlier I successfully did a complete flush of the transmission including the torque converter and a filter change. The fluid level is fine and the oil still looks like new. However lately, when I start the engine and place the transmission into D, the gear does not engage. Sometimes I have to cycle to "1" and back before it engages, sometimes I place it in N or P, rev the engine and then place it into D and even then it may not engage. After a while it will engage. Once I start driving its fine and at stop lights it seems to be fine too. This problem only seems to happen when the engine is started and it does not matter whether the transmission is hot or cold. As the Subaru is a 4WD, there is a clutch at the rear end of the transmission. There is only one adjustment screw for the band on the casing. I know that the computer does control some of the movements via solenoids in the transmission.

Disconnecting and reconnecting the battery (ie. reseting the computer) does not make any difference.

If anyone has any ideas what might be causing this please share. Thank you.

 

[MolaKule]

Not everyone here are Suburu familiar, but we have some excellent ASE members, so tell us what year, etc.

Does the transmission have a direct mechanical linkage to the transmission from the shifter, either via cable or rod link?

If it does, check the adjustment first.

Otherwise, sounds like a solenoid.

 

[redphan]

Its a Subaru Legacy 1999 model, 2.5li engine. I believe the the linkage is a rod. I am pretty certain that the linkage is not the problem, because when the car is stopped at traffic lights etc, it works fine. It only has a problem when you start the engine, regardless of whether the transmission is hot or cold.

I hope its not a solenoid, because that would mean opening up the transmission... expensive and potentially more problems down the road.

 

[MolaKule]

The clutch at the end of the transmission; is that for 4WD only; i.e., does it engage only when 4WD is activated, or does it engage for all modes?

 

[nascarnation]

When you say "flush" do you mean drain and refill or use a machine that sucks and refills?
Flushing machines have the potential for moving debris to problematic locations and you could have a solenoid that is partially plugged.

 

[redphan]

The Legacy is always on four wheel drive. I believe that the clutch at the backend of the transmission is designed to transfer extra power to the rear wheels when the car is turning or going uphill.

I did the flush myself. The procedure I followed is as follows:

1. drained the sump
2. changed the oil filter
3. added fresh oil to required level
4. disconnected the two hoses going from the transmission into the radiator at the radiator end
5. turned on engine (idling at 500-600 revs) and allowed the oil from the torque converter to drain until the fluid started to come out a bit frothy or bubbly
6. turned off engine, reconnected hoses
7. added oil upto the required level
8. disconnected and reconnected battery to reset computer
9. restarted motor and cycled thourgh gears to allow computer to learn
10. that's it. since this operation, the car has been driven about 8000 miles without problems.

 

[MolaKule]

Some possible causes:

1. Tach sensor or temp sensor or other electrical connection in transmission not conducting until engine hot. Remove connectors and reapply connectors. Check for any electrical connectors that may have been accidently bumped.

2. Solenoid not activating clutch/band apply valve until it's windings warm up.

You may have to have transmission shop monitor internal fluid pressures to really find this one.

 

[Sparkman]

I don't know the answer, but maybe this thread will be helpful.

http://www.ultimatesubaru.net/forum/showthread.php?t=14603

 

[Gary Allan]

I didn't see anyone take this approach to your problem ..so let me ask this.

How long has it been sitting when this happens? Can you come to a stop ..turn off the engine ..restart within 30 sec. and have the condition show itself?

and are you saying....

quote:

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Sometimes I have to cycle to "1" and back before it engages,

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....that it indeed engages in 1st (LOW) ...?? or that doing this little ritual causes the first engagement in "D"??

 

[ChrisW]

quote:

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Originally posted by motorguy222:


If this is the case for you,you may be low on fluid.After the fluid gets to a warmer temp,it would do better.
Low fluid could cause what you are describing.

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This si what I was going to say. Check the fluid level again (cold). I bet its low.

 

[motorguy222]

Have you checked the fluid since this was done?

If so,have you checked it any sense?

If you went by the manual as to how much fluid it reqires,the manual probably didnt cover a 'complete' drain as you did.

Most fluid changes dont cover the fluid in the convertor and only tell you how much fluid you need minus the convertor.

A normal filter/fluid change takes around 4 quarts,a full change as you did will take more than that.

If this is the case for you,you may be low on fluid.After the fluid gets to a warmer temp,it would do better.
Low fluid could cause what you are describing.

 

[redphan]

Thanks for all the suggestions. I never got round to looking into them. Nevertheless, six months on and the problem seems to have resolved itself. In total the car did about 8000 miles since the full transmission flush and the shifting etc has smoothed itself out.