P0742 - Torque Converter Clutch Solenoid Circuit Stuck On

**ls1camino** · 09-25-2012, 02:31 PM

This is in my 2000 Grand Prix...

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?

**Knight** · 09-25-2012, 04:29 PM

Any idea on the temps the tranny is reaching?

**GTP231** · 09-25-2012, 04:40 PM

Was the cooler on before the convertor incident? May want to either flush the hell out of the coolers and lines or just run a single or multiple external coolers and ditch the in radiator factory cooler

**ls1camino** · 09-25-2012, 04:42 PM

Originally Posted by Knight

Any idea on the temps the tranny is reaching?

220-240 range. I'm not sure if my sensor is getting heat soak from the downpipe, so I'm moving it to the pan. Just need to pull the pan and tap it for the sensor.

Originally Posted by GTP231

Was the cooler on before the convertor incident? May want to either flush the hell out of the coolers and lines or just run a single or multiple external coolers and ditch the in radiator factory cooler

Yes, it was flushed...just a simple tube and fin. Radiator one is not being used, just the aftermarket one.

**ls1camino** · 09-25-2012, 04:44 PM

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

**0rion** · 09-25-2012, 05:10 PM

Originally Posted by ls1camino

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

nope......but 220-240 will kill that tranny pretty quickly. Have you thought about running it back through the radiator then through the aftermarket cooler? The radiator would bring the temps down some and then the cooler would drop them further. Just from reading what you have here though I think your tranny isn't right....whether it's from trash still in it or whatever....I just don't think it should build that kinda heat with an aftermarket cooler on there unless there's an issue somewhere. What size stall does it have?

**ls1camino** · 09-25-2012, 05:20 PM

Stock converter.

**0rion** · 09-25-2012, 05:37 PM

woops...missed that the first time through. Yep....you definitely shouldn't build that kinda heat with an aftermarket cooler no matter how it's mounted. Just to give you an idea.....I have a 3500 in the fbody and it never goes much above 170-180. Anything over 200 is getting in the danger zone for a tranny.

**GTP231** · 09-25-2012, 05:59 PM

The vacuum queen has some good points.

**Smittro** · 09-26-2012, 06:03 AM

Did I miss something? I thought you swapped for a Muncie 5spd?

A 4t65e is'nt worth messing with.

IMHO go back to the Muncie or an f-40 6pd..

**Smittro** · 09-26-2012, 06:25 AM

Originally Posted by 0rion

nope......but 220-240 will kill that tranny pretty quickly. Have you thought about running it back through the radiator then through the aftermarket cooler? The radiator would bring the temps down some and then the cooler would drop them further. Just from reading what you have here though I think your tranny isn't right....whether it's from trash still in it or whatever....I just don't think it should build that kinda heat with an aftermarket cooler on there unless there's an issue somewhere. What size stall does it have?

Torque will kill the 4t65e trany faster than anything.

200-210 is normal temp for them to see.. One burnout and your over 220+.

**Smittro** · 09-26-2012, 06:47 AM

Jeremy,, what stage was your dynotech build 1-2-3?

With your numbers and that transmissions rep, imho you should have gone a minimum of stage 3 and a 3000 stall.

**ls1camino** · 09-26-2012, 06:25 PM

Stage 3...1" Chain, GMR Diff, and the regular goodies.

The 5-speed just wasn't working out...just too big of a project to tackle in the allotted time frame.

**0rion** · 09-26-2012, 07:13 PM

Originally Posted by Smittro

Torque will kill the 4t65e trany faster than anything.

200-210 is normal temp for them to see.. One burnout and your over 220+.

then there is a design problem with the tranny or stock cooler.....ATF is designed to run at 175. The rule of thumb I've always lived by is 200 or less....anything over 200 on a regular basis and you're breaking down the fluid very quickly which will severely shorten the life of your tranny. If he's seeing 220-240 on a regular basis that tells me there's something wrong somewhere.....that's way too hot for the fluid.

**Smittro** · 09-26-2012, 07:45 PM

Originally Posted by ls1camino

Stage 3...1" Chain, GMR Diff, and the regular goodies.

The 5-speed just wasn't working out...just too big of a project to tackle in the allotted time frame.

I understand bro been there myself with the f23 muncie unit I was going to run at first.

Imho the stock converter may have hurt you here.

Originally Posted by 0rion

then there is a design problem with the tranny or stock cooler.....ATF is designed to run at 175. The rule of thumb I've always lived by is 200 or less....anything over 200 on a regular basis and you're breaking down the fluid very quickly which will severely shorten the life of your tranny. If he's seeing 220-240 on a regular basis that tells me there's something wrong somewhere.....that's way too hot for the fluid.

You're exactly right,, poor design.. The 4T60e- 4T65e and quite a few others have this problem and it's well known.

Under normal operation it's not unusual for these to cook and turn their fluid black.

Usually wipes out all of the friction material aswell.

Many times once the fluid turns black in these changing it renders them inoperative.

The 2 transmissions in question are actually modified 3-speed units dating back to the 70's.

Simply put they just are not that great of a trany.

This is why the various communities (X-w-j body and fiero-etc) swap to Muncie units, and the Getrag units.

As these units stock are known to hold LSx engines all day.

There's really no GM FWD (auto) trany that will take 6-7000 rpm bitch slaps for long..

Especially if you're making any power and in many cases simple bolt ons will start to kill them in stock form, except 1 giant unit known as the 4T80e.

But it's a nearly 300 lbs trany and takes even more work to make fit and work, as well as not always easy to find as they are usually bolted to Northstars.

**Smittro** · 09-26-2012, 08:03 PM

Cont:

In general if you're running a level 3 dynotech with all the bells and wistles you'll still hear mixed reviews..

However,,, more often than not they work out fine with higher level stalls.

A 12x10 cooler is more than adequit(sp) this is what leads me to believe the stock stall shat the bed.

Remember the l67 makes great torque stock, and @ 3-400+hp/tq you're asking alot from a stock converter.

**GTP231** · 09-27-2012, 02:37 AM

Originally Posted by Smittro

Did I miss something? I thought you swapped for a Muncie 5spd?

A 4t65e is'nt worth messing with.

IMHO go back to the Muncie or an f-40 6pd..

GMPP seemed to feel otherwise as they were building them for those 1K horse Ecotecs a few years back...
With the right upgrades this trans can handle power just fine. Higher stalls build more heat as well.
That being said. Jeremy do you have the down pipe coated and or wrapped to keep the heat in the pipe? That solenoid sticking can be a heat generating source also

**Smittro** · 09-27-2012, 03:04 AM

No offense but that does'nt really explain, prove, or disprove anything.

That's great if you want to sink thousands of dollars into a questionable automatic transaxle.

Anything can be made to handle power with enough money tossed @ it.

Guess it was missed where he's having issues with a level 3 dynotech transmission.

I would never suggest a stock converter would hold up to a spooled app over 400 crank,,

No way an over powered stock converter will produce less heat than a converter made to handle that power level.

As I stated a 12x10 is plenty good enough for cooling.

I'll stick with my posts.. and my opinion that the stock stall is the cause of all the issues here.

**ls1camino** · 09-27-2012, 03:26 AM

Almost everyone in the community is running the stock stall, even with builds more powerful than mine.

I picked up a new solenoid. After looking at it, it seems that some metal could be clogging up on the screen in the solenoid and causing a fluid restriction and my heating problems.