94 4T60-E sudden loss of O/D

[TheDirtyBen]

out of nowhere, tonight my tranny wouldn't go into O/D. Tried accel./decel., shifting, etc. nothing seems to work and i'm at a loss.

[Quinky]

So your car doesn't move at all? Reverse?

Try putting it into manual first... If it'll creep slowly you busted a band...
If its doesn't move at all, you either blew up the converter or broke the stator support..

[TheDirtyBen]

no, it drives. the tranny won't go into O/D when it supposed to. i can do 70 in 3rd gear.

[Quinky]

Is the check engine light on?

[bszopi]

About 2 years ago, mine did this for about a week and then went away as quickly as it appeared... Never did figure out why it did it.

[bud36light]

Mine loses 4th and lock up only when there is alot of heat generated. IE when on a long trip, pulling something or just hammering it alot. Awhile back I came across a web site(?) that stated after the 4t60E has alot of miles on it there is a spool in the valve body that wears its bore out and sticks(because of heat). I can pull over to a rest area and let it cool for twenty minutes and it will work perfectly for a short time and then lose the same stuff. Still will shift first second third flawlessly but with no lock up. Ill get around to pulling the valve body one of these days. Looks like it might be possible with the tranny still semi in the car.

[Batman96LS]

you can pull the valve body but those "geniouses" in the engineering department designed it so that you have to take the half shaft out of the trans in order to remove the valve body cover so you can actually access both of the valve bodies.

WAY TO GO BOYS AT GM!!!!...tards.

[TheDirtyBen]

ok, pulled it into a heated garage and started fiddling around. car has a floor shifter and shift indicator is NOT mechanically controlled. i can remember that if i didn't have the indicator plugged in, the tranny would not go into O/D. But, would be fine if i plugged it back in.
Anyway, i noticed that not all of my indicator lights worked as i shifted thru the gears. well, the problem went away and the lights worked again, just fine. figured it was a bad connection that i fixed with some electric terminal lube. well, tonight it came back. drove the car about 30 minutes away and everything worked fine. on the way back, tranny wouldn't shift into O/D again and noticed that the indicator lights weren't working properly again. R and N wouldn't light.
<shrugs>

[RednBlack]

Mine did the same thing about 3 weeks before it puked. I hope your problem is different. Does it make a noise when you start it cold?

[TheDirtyBen]

not that i notice, no check engine.

[Jeff420]

i was on my way to work a couple of months ago and gunned it to change lanes and the car just revved. i got to work and thought everything was cool. when i left i got about 10-15 minutes away and the car would just rev up to 6 grand. it makes noise when i start it while in park and neutral. It can only be driven for 15 minutes and then it just revs. i started to take out the tranny and the tranny-to-engine bolts were soaked in tranny fluid.

[Quinky]

Change your MLPS... If the indicator lights are going out that tells me the mlps sensor is wearing out.. When that happens the computer doesn't know what gear range you have selected.. It's an easy part to change provided its and external one..

The MLPS stands for Manual Lever Positions Sensor, Look on the top of the transmission at the back where the linkage hooks up to the transmission.. the sensor is located right there if it's external.. some 4t60e's have an internal MLPS, in wich case you are fucked and the transmission has to come out in order to change it..

To change it just remove the 15mm nut holding the linkage to the rod that goes down inside the transmission, unplug the harness to the sensor, remove the 13mm bolts that hold the sensor to the case and gentley wiggle the sensor up and off the rod.. To adjust the new one its a little hard to explain but it has to be done with the transmission in nutrual..

Try that first..

[TheDirtyBen]

ok, i removed my MLPS, and opened it up. it was pretty nasty inside. i cleaned it up and applied di-electric grease then closed it up. well, it didn't work. so, i'm off to a tranny shop tomorrow to have the transmission tested.

[TheDirtyBen]

ok, it's fixed. took it to a tranny shop. MLPS was sending out weird readings. replaced it and everything works now.

[Quinky]

good to hear my diagnosis was correct.. I am glad that was an easy fix for yeah..