I have a 97 Dodge B2500 Conversion Van that I just rebuilt the transmission, the transmission is a 46RE. I put the transmission back in and now when I put it in reverse it either wants to die or the idle goes up and the engine starts detonating. I have been chasing this problem for two months now and I can't figure it out. I am by no means an automatic transmission guru, but I have rebuilt more than a few, and have always been able to figure little problems out. This is what I have done so far with no results, Bypassed cooler in radiator with an aftermarket one, Eliminated check ball in cooler line, Flushed cooler lines, Replaced crank sensor, old one tested good, Replaced TPS, old one had a lag off throttle, Replaced O2 sensor, old one checked good, but had a dent in the side. Went through the loom between ECM and transmission, resoldered a splice that looked questionable. Checked shift cable adjustment, I do think my cable is a little stretched, but seems to work ok. Double checked band adjustments. Drove it around for a few days manually shifting up and down through the gears, this was advice from a friend of a friend that rebuild transmissions, don't know how good he is at it..... Had valve body out to make sure everything moves freely, seems ok. The transmission works perfectly in forward gears, I don't know where to go next, ECM maybe?? Any advice would be greatly appreciated!!! One thing I forgot to mention, the van act perfectly when cold, no problems until it starts to warm up.