i'd try to manually raise the idle slightly with the accelerator pedal and your foot before shifting it into gear, hold it around 1000-1100 and see if it stalls, DO NOT try reving it more than that or some serious damage can result.

when mine did this it was my converter. you may have something else going on though. best thing would be to find a shop with a scanner that can test your solenoids to make sure they are locking and unlocking. did you flush your system before you did this, trace your wires on your tranny all the way up and make sure nothing is grounded.

I have the same EXACT problem. Please let me know if you figure anything out. I'll do the same

crap answer
 

After spending $343 at the Dodge dealership and getting my valves adjusted the answer is this... Dodge/star could not find anything wrong with the engine. Star told the dodge dealership to find out what the load on the engine was with and without the transmission in gear. Without it in gear the load was 13%. In gear the load was from 47-100%. Hence a transmission problem and not an engine problem. Now I'm pretty upset. I called ATS and they said oh... just drive the truck for about 1500 miles. That should break in the torque converter and solve the problem... So right now I'm at the point that I am driving the truck to see if the converter will break in. ATS should probably disclose problems like this that they are aware of when you buy their expensive equipment in my opinion. Hopefully this solves our problem. I won't be buying anything else from ATS though. The first mechanic I talked to was clueless. I think I just got lucky with the second guy. Too bad it cost me $343 and 6 days without a truck.

that seems crazy to have to drive something like that. but thats why we pay for stuff and don't build it ourself I guess

ATS
 

I've been driving the piss out of it for the past two days. It is still acting the same. I'll finish up on the 1500 miles then I'm afraid I will have to deal with ATS' infamous customer service.

did you ever get anything figured out??? i have same problem with my 2001. i bought truck completly stock and it would die when i droped it into gear everynow and then for bout the first two weeks... then i smoked tranny and had mine rebuilt and chose a 5 star ATS bc it was "the best you can buy" but now it dies alot!! im running manual lockup switch as well and am lost, two tc's, 3vps, 150hp injectors a lot of cussing and i have bout gave up... plz plz tell me you figured somthing out? :scare2:

im usually not one to down a company i have had previous dealings with, but i promise you i will never buy or install one of their products in my shop again. for that same reason and for the fact that their CS sucks a big one. the only tranys we use at my shop are sun coast and i have never had a single problem with them like that or with the CS of their company. point being you spend 2500-9000 on a trans and intall it, the thing should work like a champ not "drive it 1500 mile then see what happens". and honestly after we put the last one in and had issues with it i pulled it apart to see what was going on and half of the stuff they say they modify inside is not done or even touched. i was very disapointed in that product. they might make a great product for their high end trucks that they custom build, but the little guy seems to get junk and the run around. these are just my opinions, and they are like a dirty butthole, they stink. if it doesnt work out pull it out send it back and get your money back and call sun coast or DTT

when i put a ATS trans in my 01 it would do the same thing when it was cold i had to let it warm up a little longer them normal. i am know in the middle of trying to hind a nv4500 to put in my truck because my ats trans died after 12000 miles. i like the trans when it worked but did not last as long as i hoped