TCC solenoid failure mode

[Pablo]

Was driving on the freeway and noticed my TCC was not unlocking. When I got off the freeway the car stalled while coming to a stop. TCC or torque converter is definately locked up. I had to get it towed home.

I just pulled the pan and pulled the TCC solenoid and found it did have some gunk in it. I cleaned it and could easily see the pintle moving up and down without any resistance afterwards. Jiggling it would move it around with 0 resistance.

I put it all back together and I still have a locked TCC.

Am I right to assume the TCC solenoid is energized when the TCC is supposed to lock? If so, how does it work, is the ground used to switch it on and off or is the power applied or not applied. I read somewhere that applying the brake cuts the power when in TCC lock thus unlocking it. True?

What other failures would cause a locked TCC?

 

[salvageV6]

Ground from the ECM is used to switch it on and off.

However the +12 goes through the brake swich which should turn it off when pressed upon regardless of whether the ECM is giving a ground or not.

Energized is locked, can be defective mechanically as well.

Only other failure that would lock it would be a grounded line somewhere between the ECM and the transmission wiring.

Can occur inside the case as well, but it's usually the +12 wire that shorts and blows the SOL fuse.

Another failure mode could be a TCC lockup switch staying on or it's wiring shorted to ground causing 100% of the time lockup.

Brake switch should definately kill the +!2 power to it and cause unlocking.

Easily tested circuit with a good volt and ohm meter.

 

[Pablo]

Well I eliminated any of those possibilities by simply disconnecting the connector on the side of the tranny.

From what I have been reading, it looks like the valve coming off my pump is stuck...

I know little about trannies but I need to fix this. Is this valve directly above the TCC solenoid? and if so, how do i check it... IIRC theres a snap ring there right?

 

[Pablo]

#@($@#$@%@!!!!

im screwed

i pulled out the solenoid, pulled the snap ring, and the valve is stuck


REALLY stuck... i can only fit a small pair of needle nose pliers in there to try and grab the end and that sucker is not moving at all.. i tried tapping it upward to see if that would break it loose but no dice.

What I really need is a puller of some sort that I can put in there and really grab the end. The valve is very similar to the same kinds of valves you find on aircraft hydraulic components that I used to repair... we used to have pullers specifically for this purpose but I cant remember ever having one that would fit in those confines around the outer diameter of the valve end. Usually the valve had a hole in it and we would put an expanding puller into that.

I'm considering drilling and tapping the end of it for a long bolt and yanking on it. I have a spare valve i pulled from my original tranny, my only concern is that the bore diameters are the same. On top of that, im also concerned that whatever has it jammed in there is going to gouge the hell out of the bore when I yank it out. Even if it did though I'm guessing a perfect seal isnt so critical judging by how loosely the one in my old tranny sat. Lots more clearance than the flight control stuff I'm used to

Any ideas guys?

 

[Pablo]

anybody?

 

[bison]

Check to make sure the TCC valve moves freely in the bore, its probably stuck. Take it out and spray the bore and valve with brake parts cleaner. Deburr the valve. Reassesmble and make sure the valve is free in the bore. Sometimes these are a PIA to get out if their stuck. Just have some patience. Once you do this you should be good to go. Jack up the rear and get the tires off the ground and verify everything is good before you drive it. $hit ijust read your last post. You already found its stuck. Use some small needle nose pliers to try and get it out. If its really stuck you may have to pull the trans and the pump assembly will have to come out and be split open to free the valve. It will spin if you try to drill and tap the end. I wish i saw this thread yesterday.

 

[Pablo]

hmm, good point

its not even spinning though, just jammed

If i could get it to spin maybe it would break itself loose.

I don't really have any other option at this point

 

[bison]

Be sure not to nick up the bore. The valve can be replaced easily. I think it would be a hell of a lot easier to work on the bench though. Then you could take the pump apart and get the stuck valve out much easier. I hate being dripped on when working on an automatic in a car. Pisses me right off.

 

[Pablo]

Yeah i hear that, the damn thing wont stop dripping either

I cant get at it with a regular length drill bit, its too deep. Either im going to have to find a long drill bit or try and take this thing out of the car which is going to require another tow to a place where I can do that since the tiny garage in my apartment has barely enough room for just the car as it is.

 

[gtucke]

easy to check

Take the TCC out of the transmission. Next get a 12v battery that goes in a flashlight(square one) two wires one pos the other neg. Connect the neg to the battery and blow in the TCC while tapping the other wire to the pos on the battery. If the TCC is working it should stop you from blow air into it and release when you disconnect it from the pos battery terimal. If it dont replace it with a Tec Pak one. You can check the 4th gear switch the same way.

 

[Pablo]

Yeah Ive eliminated the TCC solenoid as the problem, its definately the valve that is stuck at this point.

 

[bison]

Take the TCC out of the transmission. Next get a 12v battery that goes in a flashlight(square one) two wires one pos the other neg. Connect the neg to the battery and blow in the TCC while tapping the other wire to the pos on the battery. If the TCC is working it should stop you from blow air into it and release when you disconnect it from the pos battery terimal. If it dont replace it with a Tec Pak one. You can check the 4th gear switch the same way.

If its locked in 1st, then it cant be the solenoid. The circuit exhausts when it goes into 1st. The only way it could stay locked in 1st is if the valve is stuck in the bore.