P0740: does an '02 GC have a tcc solenoid?
 

Good morning all. I've got an '02 Grand Caravan with the 3.8 and 160,000 miles. It's a little banged up now, but it's been a great car for the most part. I had a problem 3 or 4 years ago, maybe more, and replaced the transmission solenoid pack. It was a simple fix and has worked well since.

Now, my CEL is on and my simple code scanner shows a P0740 code. I can clear it, but it comes back fairly quickly. The only problem I have noticed is that there seems to be a very slight shudder as I am slowing down just before the car comes to a complete stop.

I'm sure the best solution is to go to a shop/dealer and have them test the tranny on the right machine, but at this point, I'm not sure the van is worth it. It's a little beat up and has seen better days. If the torque converter is going out, it may cost more than the van is worth to have all the work done. But, in other forums (for the trucks I believe) I have seen mention of swapping out the torque converter solenoid. At least on those threads, it sounds like a simple task and might be at least worth a try. But when I check my local parts store's web site, they only show a TC solenoid for a 3 speed transmission and mine's a 4.

Does anyone know if the 4 speed has a separate TC solenoid in the tranny that is separate from the solenoid pack? If so, could this be the problem? And lastly, if it could be the problem, is it an easy job to replace one?

I know that sounds like a lot of questions, but THANK YOU to anyone and everyone with any ideas.

If you have the transmission that has the 3 bolt solenoid pack next to the fill tube , the TCC solenoid is integrated into that assembly......that code could indeed be a slipping clutch in the converter, you could remove pan and see if TCC clutch lining is in bottom of pan..If tranny is very clean, then it may be worth investigating.....PO740 is generally internal but not always....

Thanks for the advice, and I was afraid of that. On the dipstick, the fluid looks and smells clean, but I'll try to pull the pan off and check there.

Any idea of a rough estimate on getting one rebuilt? I think that job is above my skill level.

Also, any chance a voltage issue could cause similar problems? It's a long shot, but the bearings in the alternator have been whining for a while, and it's gotten to the point lately where I'm sure it's about to go out.

Thanks again.

This obviously doesn't pertain to your transmission but if you have your alternator replaced, be sure that one with the clutch assembly is used. If it isn't, there will be a noticeable vibration at idle.

Anything is possible.......PO740 is triggered whenn the tcc is commanded on, but the computer does not see the rpm drop.....it is a code that can be hard to determine the actual root cause because it can be mechanical,hydraulic or electrical....I always thought it best to first check for debri because there is not much use of looking at other ideas if the trans wasnt long for this world anyway... Costs of repair can vary...I would call the local dealer to get a price on a factory reman and that will give you the max price then start from there to get your quotes...

Thanks for all the advice. I dropped the pan last night. The fluid didn't look to be in too bad a shape, and I didn't find any shrapnel in the pan. There is a little magnet over in the corner that was covered with some kind of grease. It looked hairy because there were certainly some fine particles in it, but nothing big enough to be noticeable when I pinched it between my fingers. I'll head over to the parts store this weekend to pick up a new filter and some ATF+4 so that I can put it back together.

Without a bunch of metal in the pan, then maybe it is worth taking to a shop for diagnosis. I just hate the thought though of pouring a bunch of money into a lost cause.

Will update if I can figure out (and afford) what to do next, but thanks to all again.

By the way, speaking of a torque converter going out, I really have no idea how these front wheel drive transmissions are set up (is it even a "transmission," or is it more properly called a "transaxle?"). If the shop determines that the torque converter is the problem, can you replace just the torque converter, is that much cheaper than rebuilding the entire transmission, and is it advisable anyway?

Maybe I should start a new thread on that question.

Transmission or transaxle will suffice to describe your unit.......Yes torque converters can be changed independently from transmisison repair,but there is a risk involved if not properly inspected.....Since yours is clean , I would think that a descent trans shop can take a cooler flow reading and if the flow increases dramatically when tcc is engaged, then the problem is in the converter ( 99%of time )...There is a slight chance the problem is in the pump, but the odds are in favor for a simple converter replacement solving your problem ( at least in the short run until this unit does give up the ghost for other issues that can occur)...If the cooler flow check does not increase dramatically when tcc is commanded, then replacing the converter will be no value to do...