I own a 2003 Town & Country LX with a 3.3L Flex-Fuel engine. The vehicle has had a trans pan seepage/leak since new. While it was initially minor, it got worse recently. I have never had to add trans fluid. Over the weekend I dropped the pan, and relaced the filter and gasket to fix the leak. The pan was clean inside, and the fluid was a nice clear red. I was very careful, to clean out the pan (even washed it with soap and water, and dried it thoroughly)

I filtered the used fluid through a coffee filter, and added it back to the trans. Then, I topped off the system with just under a quart of Valvoline ATF4. Now there is a very noticble "clunk" when the trans downshifts at approx. 35mph. Any ideas?

 

Possible that you had air in the system, also did the new filter come with an oring on it? If not the pump is sucking air. The trans controller will have to have a quicklearn function done to reset its prelearned values (causing the downshift clunk)

 

Thanks for the reply - I did make sure the o-ring was present, and lubricated it with clean fluid before installing. I also let the van run for about 5 minutes in neutral after refilling, and then put in reverse and all forward gears for a few minutes before backing off the ramps.

How do I do the "quicklearn" to the trans contoller?

 

Unfortunately you cant. Something that would have to be done at the dealer, unless you know of a repair shop that has good diagnostic equipment. Is possibly could have happened because you ran it in Neutral.

 

Are you saying that the trans will never re-learn itself? Is it mandatory to have a dealer reset the codes? I just changed the fluids in my '97 GC, and I think my tranny is running worse than I started with. I had run the car in gear with the lines pulled to purge the old fluid, and actually went through 12 qts of ATF+4 to get it all clean. I don't recall if the filter had an o-ring, but I know it snapped into place at the tube.

Matthew

 

Ive never seen one relearn itself, if it does you would have to live with it for at least a thousand miles. The problem is that you would have to make the same shift numerous times under the same conditions that is causing the harsh downshift for it to relearn. Its faster and less aggravating just to have the TCM reset so it will start the relearning process faster. If yours is doing it, its because you kept pumping the transmission dry and the pressure switches kept tripping causing the TCM to learn that there is a problem with the low/reverse clutch which is on as long as the engine is running. Its not wise to change transmission fluid that way. I see the point, to get as much new fluid in as possible, but in the long run if you service your trans every 30K there is no real good reason to change the fluid that way.

 

Concept was good, to change maximum fluid, but method was not. If fluid is really bad I will usually just drop the pan again and replace fluid 5-10k miles later and exchange that way. Brandon is right, it really needs a quick-learn to restablish base values. It takes 10 minutes and they will charge for .5 - 1.0 hr. to do it. These trannies are a learning tranny and it would eventually re-establish values for your driving habits, but it could take a loooonnngg time and possibly cause a problem. Quick learn gives it safe starting values to learn from. A private shop with the Snap-On MT2500 diagnostiic tool should be able to do the Q-L if you don't want to go to a dealer. I've never heard of idling in Neutral after a service causing a problem. I do usually cycle through the gears a few times and let it idle before putting it back on the ground.

 

To be honest, I perfromed my procedure with the hoses after reading it on this forum. If someone had noted the potential problem with this on that thread, I surely would not have done it.

But I will say that I don't think I let anything go dry. I kept adding fluid with a funnel until it came out clear. If it doesn't start learning before winter, I guess I'll have to take it to the stealer.

Matthew
'97 GC 3.3 "Sport"