I have a 2014 Ram 1500 with the 8 speed automatic. I bought it June of this year with 39000 miles on it, currently it has 45000, A few weeks ago I took a trip to Richmond (about 90 miles away), was parked for several hours, & then returned home to Waynesboro Va. On the trip home I pressed the gas down the truck lurched forward and there was a thump. I let off the gas and the transmission shifted back into 8th. The transmission was around 220/226 degrees at this time and had a whining sound. Called the dealership to setup a recall visit & asked them, they told me that it was within temp spec. They updated the software, checked trans fluid, and said it would go through an adaptive transmission relearn. A couple days later I had this happen again when going to Roanoke. Same trip around 90 miles, went to downshift and truck lurches forward with a thump (like its bogging down). Generally from what I can recall since I had the truck always stays between 180 & 190 on transmission temp when this occurs the transmission temp is around 220. Not hauling a trailer, not loaded down. Only load on vehicle is passenger. I drive 30 miles each way to and from work and it doesn’t seem to get this hot ever. Any ideas or is this normal for this transmission?
220 seems awfully high for this ZF 8 speed. My ZF 6 speed in a Mustang rarely exceeds 195 in stop and go traffic and can’t get past 180 running down the highway. From your description of the problem, the transmission seems to be going into a “safe” mode when it gets hot - but the dealer should know this. This may take some diagnostic time. If the truck’s transmission data is scanned while driving to the conditions you see, i.e. 210 plus and then a clunk, the scan will allow the tech to see what might be wrong. The whine may be the pump making noise at high temps. Maybe the torque convertor clutch is not locking up. That would add a lot of heat to the system. Maybe the trans cooler is clogged with debris, a pinched cooler line or maybe the thermostat inside the transmission has failed preventing flow to the cooler. You should be able to see that on the temp gauge. The t-stat should open about 190 and temp will drop pretty quickly into the mid 180’s. If it just continues to climb, I’d say that might be the problem.
Maybe visit another dealer or an independent transmission shop for diagnosis.
Another source of info could be at allpar.com - a site that specializes in Chrysler products. I’ve found good help at their minivan forum several times over the years.
Maybe change the transmission fluid, just as a cheap start? Could make all the difference.
Let the chart be your guide.
Tester