I have a 91 legacy fwd with AT. The trans seems to be shifting fine but I have noticed that over 50 mph my rpms are high and it rarely will go into overdrive. The trans fluid is full but I do not know what else to look for.Could you give me any suggestions to fix this problem? thank you

If the fluid is nice and red it's good, if it's dark and black... it's bad

some where in between.. might as well change it.

Is that all the time?

 

 

nipper

i have issues like that when i deicded to drive before letting the car warm up completely. after about 2miles it's fine

My trans fluid is fine good level and color.

 

I have a 25 mile drive home, the car is well warmed and still will not go into OD.

 

Is there some type of switch or vaccum connection that controls this function?:-\

The transmission is almost 100% electronic. If I recall correctly, the Thottle Position Sensor is what the TCU (Transmission Control unit) uses to decide whether to lock up the torque converter (because there is no Overdrive in these cars). It may be that the TPS needs cleaned and then the TCU will decide to lock up the torque converter.

 

Exactly what is "high" RPM's to you? At 60mph, the RPM should be around 23-2500 and at 70mph, the rpm should be at ~3000.

by what he's saying it's staying in 3rd and not shifting into 4th.

 

the 4EAT transmission will stay in 3rd until it reaches a certain temperature. i do not know the circuit or sensor location for this function but it may be related to that. i'd probably look at a wiring diagram for your transmission and see where that sensor is, then test the resistance of it per the FSM values.

 

what do you mean by "good color"? how many miles on the trans? when was the fluid changed last? how long ago did it start doing this? any other transmission issues ever? any major engine/trans work done to the vehicle recently? does it have an aftermarket transmission cooler on it?

I want you to try this.

 

Once the cars temp gauge is in the middle, drive it as you would, but shift it manualy. start in 1, then 2, then 3, then 4. I want to see if it goes into 4th, then lockup.

 

Lockup drops the engine RPM by aprox 300 rpm. Lockup occurs in all gears.

 

Next drive the car in drive 3, and hold the rpm at something resonable and see if lockup happens.

 

Does your tranny temp light come on when you first start the car.

 

And as was mentioned when was the last time you had the fluid flushed.

Does your CEL work. Something else that may affect it is loss of the VSS sensor.

 

nipper

MY CEL works and goes off when I start the car. There is no at temp lite( manual says only AWD models). Trans fluid is good looking and full, flushed about 35k ago.

 

Drove it today. There is no lockup in any individual gears, the rpm tops out and with the throttle steady on fairly level road it never drops. I remember getting lockup in the 50 -55 range, always noticed it before. My wife has been using it since summer for mostly city driving so I just have not had the opportunity to notice what it does. Other than this the trans shifts fine .

 

I do not know where to start with this. Thank you.

Time to have a dealer look at it. It sounds like you may have a bad lock up solenoid.

 

nipper

Like Nipper says but if you feel

ambitious you could wire a LED

to the signal wire from the TCU.

 

I built this

 

to monitor my Legacy's 4EAT.

One of the indicators is "TL" which

indicates when the TC is locked

The entire post can be seen here

4EAT monitor