Now I've Done It! Lost OD and TC, No Shift

[Drg racr]

I think I've really screwed myself now with my 94 Ex. Today besides the TC not locking up, I've lost OD now. When I came to a stop, I tried taking off easy, and it took almost 5000rpm before it would shift into second, and it shifted so hard I thought the driveshaft would spit out the back. I stopped again, and I manually shifted the trans; it will shift, but not like it should. The fluid is ok, all the connections are good.
I read on one of the threads that it could be a TPS or VSS sensor. I checked the TPS, it reads fine. The speed sensor, I have no idea how to check voltage readings for it. If this isn't it, the solenoids must be inop. I haven't pulled the pan yet to check the screen, but the fluid looks clean and red.
Any ideas, or am I looking at a cooked tranny? If the trans is bad, there's no way I can afford to fix it. Parts truck?

 

[BrooklynBay]

Your A4LD transmission uses 2 solenoids (overdrive, and TCC). Start with the internal wiring harness. Is it unplugged from the main harness? You should have a constant (+) on one terminal. The solenoids get a ground signal when the computer tells them to apply.

 

[MrShorty]

I think I've really screwed myself now with my 94 Ex. Today besides the TC not locking up, I've lost OD now. When I came to a stop, I tried taking off easy, and it took almost 5000rpm before it would shift into second, and it shifted so hard I thought the driveshaft would spit out the back. I stopped again, and I manually shifted the trans; it will shift, but not like it should. The fluid is ok, all the connections are good.

Have you lost 4th gear only, or does it not shift correctly at all? You describe problems with the 1-2 shift, which is hydraulically controlled with no input from the computer.

Basically, if you are having troubles with 1-2 and/or 2-3 shifts, then the problem is not with a TPS/VSS or other EEC-IV component. The problem is in the transmission. Perhaps the vacuum modulator? Is there ATF in the vacuum line to the transmission?

 

[Drg racr]

Sorry, I kind of combined two problems into one.
The 1-2 and 2-3 shift wasn't happening until you got the engine prm into the stratosphere, although I could manually shift with the shfiter and get it done, albeit a harsh shift.
The TC lockup and OD problem I figured would be the speed sensor or something similar.
I fiddled around with the truck today, and after driving it for a little while, I got it to shift 1-2 and 2-3 like normal again. I have no idea what I did, but I'm sure it will do it again. I have a feeling my transmission is slowly eating itself. The fluid is normal, no leaks, hoses good, connections good. Modulator is new last winter.
I'd like to know what others have experienced just before their transmission went sour.

 

[Glacier991]

With your 1-2 and 2-3 shift issues...you could be having governor probems as well.

Your TCC and 3-4 very well are as you suspect or somehow related to a lack of 12V to the common lead.

I think it is premature to assume you are dying here. Keep up the 5000 RPM stuff and it won't matter.... you'll kill a sprag.

 

[Drg racr]

I popped the tans pan last night, wires all looked good, fairly clean inside. I changed the filter as long as i had it apart. No clutch pieces in the pan, although I found a strange shiny piece of round machined metal, about 2mm in diameter or so, about half that thick and flat. I have no idea what it is, but I'm sure it's not just regular junk you find in the bottom of an oil pan.

 

[BrooklynBay]

Could you post a picture of the metal fragment? Did you check the wiring harness with a test light to see if there is power on it? Did you check the resistance of the 2 solenoids?

 

[Drg racr]

No, I didn't check the resistance in the solenoids. I did check the harness, it does not have power. Does it have to be in drive for it to have power? I'm thinking of splicing a wire with an indicator light into the harness to see if its powering up when I drive it. Which wire is the power wire? There are two plugs going into the trans on the left side. Maybe I tested the wrong one?

 

[BrooklynBay]

You have to ground the test light, then test the middle connection on the 3 pin harness for (+).

 

[Drg racr]

Actually both harnesses going into the trans have 3 wires. But, the lower harness looks like the right one. I tested it, and I have a solid 12 volts going to it. Just for fun, I tested the other harness, and it has barely 3-4 volts going to it. Just enough to get my little light to glow slightly.
Another wierd thing, yesterday it kicked into lockup, then I hit a big dip in the road and it kicks out again. Strange.

 

[Drg racr]

Here's a freaky tidbit for ya. I tried to start my truck yesterday, and all the electrical power shut off when I hit the starter. I checked the battery cables, and one was loose on the terminal. Not much, just enough to look like it was tight. I tightened it, and now my lockup works again. Could this be the problem? I hope it's this simple!

 

[BrooklynBay]

The PCM needs a constant supply of electricity to keep its memory. Intermittent glitches could affect it.