Thread: P0742 - Torque Converter Clutch Solenoid Circuit Stuck On

This has happened twice now, once on the three hour cruise home from my tuning session last Friday and once again this afternoon. Both times happened during highway cruising and while in 4th gear at about 70-80mph. The car will start bucking, and if I give it some gas, it will smooth out and will be fine.

Some background: This is my Dynotech transmission. I installed it with my turbo kit and it ran for about 20 miles before the torque converter failed and sent metal shavings throughout the entire transmission. Long story short, I had it torn apart, cleaned up, and reassembled by a shop. I reinstalled the transmission with a stock torque converter with brand new fluid in everything. Now this problem. I talked to the shop that did the rebuild and they think the solenoid may be jammed up from the shavings.

Somewhat related, but I'm not sure...I can't keep my transmission as cool as I want. After some spirited driving, I have steam coming out of my dipstick and the fluid smells burned. My friend believes the fluid is breaking down due to the heat. I have a finned pan and a 12"x10" external cooler mounted in front of the A/C condenser. My next step is to put a 12" pusher fan in front of the cooler. This will be happening on Saturday.

Any ideas? Is the transmission just getting too hot or do I have to replace the solenoid for the torque converter?

Another point...my tuner turned off torque management and changed the shift points to 6000. Would either of those adjustments make a difference?

If your original converter failed and sent metal in the trans then the tcc solenoid definately has some in it and is restrictive which will cause code P0742 to set and lockup operation to act up and can be harsh and cause the car to feel like it is bucking under load as you experienced. TCC release fluid goes through the tcc solenoid.

Do you have the ability to scan data to view trans temps? A failing torque converter not only puts a lot of fine metal debris in the trans but also will go in the cooler and can definately restrict it if not completely block it- which can also cause tcc problems and wipe out a new torque converter. A restrictive or plugged cooler will cause the trans to run very hot and can cook the fluid in a short matter of miles and also cause premature wear to the geartrain in the transmission and bushings as their lube fluid comes from the return side of the cooler.

The cooler is fine. It is an aftermarket tube and fin. It got blown out before being used on this trans. I don't have a problem doing it again.

As for the solenoid, can it be replaced without dropping the transmission?

Sure it can.
http://www.grandprixforums.net/how-t...ess-54448.html

Use those to the point of getting the side cover off. (Early on) At that point you are looking at the soleniods. Then swap your one soleniod.

I have a friend saying that my heating problems are from using a stock converter in a built trans and putting down 400+ hp. He's also thinking that my unwrapped downpipe could be causing issues too.

Stock converter on a built trans isn't likely the cause. I've seen that done too many times to think it's real. If you had a super high stall, that may generate heat.

this is an old thread but I was compelled to reply
I've had THREE 4T65E in 2 different cars exhibit the torque converter clutch stuck on symptoms, and after changing 2 transmissions and having it happen again with a replacement trans, I have a pretty good handle on what's happening. the replacement trans in the 2003 not only had a stuck TCC, but also a sluggish, delayed 1-2 shift.
these transmissions are sacrificial in that the TCC itself sends clutch dust through the trans that eventually clogs up the valve body solenoids. it's unbelievable how much clutch dust was in the pan of my Monte Carlo when I pulled the pan. it was like a quarter inch or more thick of mud. both of our Monte Carlos (2001 and 2003) started having stuck converter clutches and shifting hard. I would actually drive them like a stick shift by lightly pushing the brake pedal down, then shifing them manually 1-2-3-4. the problem would go away and come back weeks later, but in the 2003 the problem stayed permanently- i.e. the TCC was stuck from the time it was started up cold.
first off, you can get around this problem by cutting the BROWN wire on the transmission harness, at the bottom of the harness plug. that disconnects the TCC. I wish I had known that sooner and I may have not changed 2 transmissions, but with 200,000 and 185,000 on each, they were going to need it anyway.
then the 2003 got the problem again- with the replacement junkyard transmission. I cut the brown wire to TCC and it drove "ok" without a stuck TCC, but still had a delayed 1-2 shift. in that one, I had a local garage put it on a lift, pull the side cover, and change the four 1-2, 3-4, TCC, pressure control solenoids- and also the flat manifold shift position sensor switch.
PRESTO- fixed. it shifts like a dream now. I had also bought an accumulator shift kit but don't think I'll even need it.
so- I tested all four of the OLD solenoids with a 12 volt DC converter, and checked all 4 of them with an ohmmeter- guess what-
all 4 are within specs for resistance readings in ohms, and all 4 click when 12 volts are put to them, and release when power is removed
but now the kicker- they click and release sluggishly, not quick and crisp
so - these solenoids can be bad, even though they still work- they work slower than they should, that triggers the long shift code,
which in turn causes the PCM/TCM to up the line pressure to the max
the high line pressure, sticks the TCC solenoid on- it fails to release
if you have this problem, cut the brown wire- and see if it goes away.
if it does go away, have the 4 solenoids and manifold changed. that will probably fix it.
if it still does not go away, then put the accumulator shift kit in.
if the solenoids and trans accumulator spring kit do not fix the trans, it needs a rebuild- the trans has developed excessive clearances or bad seals in the drums/clutch packs.
or, there are other stuck valves in the valve body itself.
all this is worth trying first, because these trans units cost a schitload of money to rebuild, I was being quoted $2100 and up
I could buy another identical car for $2800 with half the miles on it and start over again, it's not worth it
the transmission shops are raping on these repair bills.
they wanted $600-$800 just to put the solenoids in,
but I found an independent general repair garage- not a trans specialist- who put the solenoids and manifold in for $265
he was unsure if the trans had to be pulled again, I advised him the solenoids can be changed in he car, by dropping just one side of the subframe
I bought the solenoids on Ebay for around $100 shipped.
so there is a cheap fix to the problem. for around $400.
if I had a lift, I'd put them in myself. but my working on the floor days are nearly over at my age...
the clutch in the torque converter is a bullschit device put in there so the car can escape the "gas guzzler" tax when sold new by the car maker,
it does not just engage solidly in these cars as designed- it cycles on a "duty cycle" so it engages/disengages many times a minute or even second,
to give an average engaged time. so it will start operating even 2nd and 3rd gear at some times- all this for a few mpg.
but what this does it wears the TCC clutch down and sends clutch powder particles throughout the trans.
this is why they have a magnet in the pan, to catch as much as possible. and one GM service bulletin actually states putting a 2nd magnet in the pan.
to catch particles that are circulating through the trans- BY DESIGN. it's a total compromise, and a schit system actually.
all because the government mandates gas mileage standards, and taxes gas guzzlers on the showroom floor.
that's all it is. if the TCC was never in there, this problem would not even exist. and these transmissions would last a lot longer.
the clutch packs would just wear out with time and be a lot easier to diagnose, and cheaper to rebuild- without all this complexity.
I'm convinced a lot of these cars get junked because of this silly problem. and a lot of transmissions got high dollar $$ rebuilds when it was just a few solenoids.
cuz I've seen a ton of nice Grand Prix, Bonneville, Monte Carlo, etc. 4t65e cars in the junkyards, with mint interiors and nice sheetmetal-
that really should not even be there, they should still be on the road.