Auto Trans advice needed please

[markfagus]

Guys, I have a 88 3.0 auto. When I bought it a few months ago it had been sitting for 2+ years. I did the head gasket and a few other issues and now am tackling the tranny issue that has been there since I got the truck.
It shift fine in R and thru 1-2-3 but will not go into OD. I disconnected the computer under the console and test drove it shifting manually and OD did engage. So I assumed it was a solenoid issue. I replaced the solenoids (all of them) and I am still not getting OD.
I initially checked everything under the hood so I know it is not an issue there.

Could it be the ECT computer that is an issue? Do these things ever fail? Or is it time for a rebuild on the tranny?

Any advice you can give is greatly appreciated!

Mark

 

[4runner_kid]

Guys, I have a 88 3.0 auto. When I bought it a few months ago it had been sitting for 2+ years. I did the head gasket and a few other issues and now am tackling the tranny issue that has been there since I got the truck.
It shift fine in R and thru 1-2-3 but will not go into OD. I disconnected the computer under the console and test drove it shifting manually and OD did engage. So I assumed it was a solenoid issue. I replaced the solenoids (all of them) and I am still not getting OD.
I initially checked everything under the hood so I know it is not an issue there.

Could it be the ECT computer that is an issue? Do these things ever fail? Or is it time for a rebuild on the tranny?

Any advice you can give is greatly appreciated!

Mark

The ECT has nothing to do with the OD. I would start tracing wire's and make sure there isn't a short for the shift solenoid's. That's where i would start, make sure your getting power at the solenoid's and at the computer.

 

[markfagus]

I thought the ECT controlled the shifts and that is why I got OD to engage when it was unplugged?

 

[4runner_kid]

I thought the ECT controlled the shifts and that is why I got OD to engage when it was unplugged?

ECT control's the RPM's the transmission shift's at. When the ECT is on it shift's at a higher RPM then if it was off giving more power.

 

[markfagus]

is the computer under the center console for the ECT? I am puzzled why would it go into OD when that was disconnected and I shifted manually but not any other time.

Sorry to sound like an idiot!

Mark

 

[fourwd1]

ECT stands for Electronically Controlled Transmission. The ECT ECM controls all aspects of the trans operation, including when to shift in or out of OD, based on input from various sensors (speed, rpms, coolant temp, etc), the EFI ECM, and the Cruise Control ECM.

Second, are you maybe confusing the lock-up of the Torque Converter with the OD?

Third, have you checked for any trans error codes?

 

[markfagus]

FourWD, thanks.

I dont think I am confusing them. Before I did the manual test it was definitely not shifting past 3. I could feel it shift from 1-2 and from 2-3 and that is as far as she went. My RPM's were very high. Don't recall exactly but over 3000 rpms at 50-55 and when I hit OD button on/off nothing changed.
I definitely know something is not working the way it should.

Have not checked the codes yet.