1990 Acura Legend transmission disengages

JCORNISH73

MEMBER
1990 ACURA LEGEND
6 CYL
FWD
AUTOMATIC
151,213 MILES

This car has a strong engine.
The problem is that when I drive it for extended periods, 1 1/4- 1 1/2 hours at highway speeds, consistently the car slips out of gear predominantly with heavy torque such as climbing up a hill.
I have to pull the car over to the side of the road and after the rpms lower I can get it to start engaging again. After this happens, it lags into gear and shifts improperly. After I stop the car and allow it to sit and cool down, the transmission will engage once again.
It doesn't shift very smooth but it doesn't slip out of gear.
I cannot depend upon this car for driving distances, it has become a local driver.
Is the transmission failing or is there another problem?

3 Replies

KHLOW2008

MECHANIC
41,815 POSTS

Hi jcornish73,

Thank you for the donation.

Possible causes are :

1. The transmission could be failing.

2. Check the fluid level. If the fluid level is low, or too high, it can result in slipping.

3. Strainer clogged. The strainer is inside the trans and cannot be replaced unless the trans is disassembled. Once the strainer is clogged, the trans is most probably failing.

4. Is the D4 light flashing while driving? If yes, an error has been detected and you need to retrieve the trouble codes to understand what is affected.

If the speedometer is not working, shifting would be erratic.

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Thursday, July 22nd, 2010 AT 12:47 PM

JCORNISH73

MEMBER
2 POSTS

Fluid level and color are fine.
No d4 flashing light.
The question I have is why after driving duration does this slipping occur when it handles inclines and acceleration like a champ at all other times.
It seems as though fluid heat/fatigue or engine heat play an important role in this.
I drove it to the same place three separate occasions and it happened in exactly the same place during two trips up a steep incline; the third time I drove it on a different road avoiding the incline and the same thing happened almost precisely the same distance when I wasn't driving an incline. All occur after duration of about 60 miles driving at highway speeds (perhaps a bit faster!) After I limp into the destination, I stop the car and when it cools/rests it returns to "normal".
I've already contemplated a problem with the transmission; I need to wrap my head around why it happens at temperature and/or fatigue?

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Thursday, July 22nd, 2010 AT 4:44 PM

KHLOW2008

MECHANIC
41,815 POSTS

Does the S3 indicator light comes on for 2 second at intitial ignition ON?
Is the S3 light blinking while driving?

No temperature sensors are incorporated in the transmission system so it should not be a temperature sensing problem.

Possible causes for such symptoms are :

1. Fluid quality. If the quality of the fluids are poor or the grade are not to specification, it can cause either slipping or harsh shifting.

2. Internal fault. Transmission is failing. When the trans heats up, pressure is leaking internally somewhere causing the slipping.

3. Transmisson Control Unit fault. Electrical components can fail, when heated up due to faulty internal circuits.

4. Control Solenoids. When solenoids heats up, they can fail.

5. Clogging of fluid passages. When insufficient fuids are getting to the fluid pump, pressure would drop.

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Friday, July 23rd, 2010 AT 8:46 AM