Problem with 1999 Dodge Ram
I have a 1999 Dodge Ram 1500 SPORT, 5.9L automatic. I just swapped the transmission with a rebuilt unit. Now after a minute or two of driving the OD lites comes on and it downshifts and a couple minutes after the Trans Temp lite comes on. I have checked the
transmission cooler and the transmission and the temp is never very hot. I have an A-piller trans temp gage which reads the trans cooler line temp and it reads normal like it did before all this. No other problems, no hard shifting, no slipping. I have driven on 20/30 min trips with no problems. Any thoughts

 

I would recommend checking the electrical connection going into transmission. If no problem is found:

Contact rebuilder and let them know what is going on. Check fluid level (in neutral) and make sure it is OK.

Other options (may void any warranty, if any)

Drop tranny pan
Remove governor solenoid and governor pressure sensor and make sure they are clean. Make sure connectors are tight.

Delete check valve in cooling lines.

Welcome to DF.

 

i would expect the trans cooler lines to be pretty hot. the hot line should be too hot to hold and the return line should be nice and warm.

if you did not already remove the check valve and flush the lines and cooler, it may be stopped up and you might be getting a false reading on your temp gauge. i would temporarily disconnect the return line and at the radiator and point it into a bucket, crank the truck, shift to neutral and do a flow test. it should gush.