The milage on my 2005 Dodge Ram 2500 when I had to replace the transmission was 109,242. I was towing a 12,000# 5th wheel at the time - across the desert from Albuquerque to Bakersfield during the month of August. This involves several long mountain climbs and the temperatures were between 95 and 105 degrees. I DO NOT believe these conditions justify a transmission failure, but the end result to me was $4,493.28. This included the Jasper transmission, the installation of an Allison Cooler in front of the radiator, the install kit and the labor. Since that time I have also lost my #4 injector which is totally unacceptable for this to happen at 138,832 miles. However, my present mileage is about 214,000 and all is running well. Hope this information is of some value to you.
I should add that I have made several other trips with the 5th wheel and a smaller RV trailer on the same route as well as a 10,000 mile trip back to Georgia, Louisiana and Missouri with the smaller RV - all without incident.
I have to disagree,a trans issue at over 100 k towing is not unreasonable.The number 4 line has been a known issue for years-in almost every case I have come across the line support has been loose.In many cases they rattle loud enough to be heard above the engine sounds.In 06 the line and mounting was updated in production.