Torque Conv Not Locking Up

[Drg racr]

If the torque conv is coming out of lockup, could it be the speed sensor? It doesn't do it all the time. It will not lockup for a few days, then all of a sudden it will be fine the next day. The truck shifts fine, all gears work fine. It's got 127000 miles on it, and it's a 94 Ex.
Where is the speed sensor?

 

[MrShorty]

Yes, it could be the speed sensor. Of course, it could be several other things, too. I would start by running the EEC-IV self-tests (aka pull codes) and see if the computer has seen a problem. That can get you started in the right direction.

I'm not sure on a '94. On my '92, the VSS is attached to the end of the speedo cable on the rear output of the t-case. I understand that, at some point, they started using the ABS sensor on the rear differential, but I'm not sure when.

 

[Glacier991]

The sensor moved to the rear differential in 98.

 

[Drg racr]

I checked the codes, the only one I found was a code 114, which is an Air Charge Temp sensor out of specs. That may explain my bad gas mileage in the winter. Will the VSS throw a code if it's bad? What else could it be?
The trans hasn't acted up in over 5 days, so maybe it was a fluke. If it does it again, I'll check it out, otherwise, I'll just keep driving it as is. It has a tranny cooler, so I'm not worried about overheating the trans.

 

[Glacier991]

The VSS could be your problem, and so could a shorting brake on/off switch. (Just thinking off the top of my head here). Other inputs used by the computer for TC apply determination are MAF sensor, Throttle position sensor, engine coolant sensor.

Inside the VB, you could have a torque converter shuttle valve hanging up, the torque converter clutch shift valve hanging up, or foreign matter in the solenoid valve preventing closure.

 

[Drg racr]

This is the reason I prefer a manual transmission. It's a lot simpler to work on!

 

[Drg racr]

Well, it's still doing it. I'm going to take it to a buddy's garage and see if he can figure it out. It's getting warmer outside, and I don't want to cook the trans yet. If the trans is fried, it's getting converted to a stick!