lock-up converter "woes"..????

[Mister Fiberglass]

..........gota situation here.

94 2500 .....shifts GREAT...goes into hi-gear and lock-up w/o a problem but it seems to come out of L U at a whim and will NOT go back in(for the most part) UNLESS you come to a stop and then if you go through the gears it is OK.

It does not do this all the time BUT it is aggravating when it does happen.

Electrical switch?

[ol ron]

you have a partially plugged lock-up port in the valve body, or the TC is toast. Call Bill kondolay at Diesel Transmission Technology and get a reliable answer. Look at the Links pages on the Turbodiesel register site to get his phone number. He is the guy with the good answers.
Ron

[Mister Fiberglass]

o l .......IF the port was part blocked ---why would it always work on a up shift and stay locked-up for awhile? And when it locks up there is no slipping and sliding - it chrisply goes into L U and pulls great. AND when it is in LU mode and I tap the brakes it goes OUT of LU and does not go BACK in but maybe 10% of the time. AND if it does it takes quite a distance to do so. A bud has a Ferd truck with LU ....you tap the brakes and it goes out of LU and then BACK in within 2 or so seconds under lite throttle/no load situations. This whole deal is a pain-in-the-arse !!

[fox]

I have been watching this topic for a few days and now remember that my 95 got temperamental with the lock-up . I simply unplugged the harness at the trans and re-plugged it a few times and it never happenned again. Have you tried that?
It sounds like the wires may be moving around in the wind under the truck.
you may need to find the wire at the trans that gets grounded to put it in lock-up, attach a long wire to it and take it to the cab so you can connect a vom and go for a drive. This test will determine if it is a hydralic or electrical problem.
Good luck-let us know.

[John Kunkel]

Throttle Position Sensor

[mopartec]

the throtle postions sensor is probably worn out. replace it and make sure it is properly adjusted to read 1 volt +-.2 at idle with the engine off.also the temp sensor on the trans cooler line go bad at times will also cause lock up to hay wire but that also will affect overdrive also.. and latley with high milage diesels i have been seeing crank sensors go bad . but if the crank sensor go bad the charging system and tach go haywire also.