Ever since I installed a trans. temp gauge my trans has shifted differently. I don't believe that the install on the guage caused the change but what do you think? When the truck is in overdrive and you accelerate past 35mph. and the truck reaches 40to 50 mph all is well. If you keep the trans in overdrive while slowing down then the truck downshifts to second gear at about 20mph. which is the way it has always been. But if you take out overdrive and reduce speed from over 35 mph the minute it gets back to 35mph it downshifts to second gear. The problem is mainly when in slower traffic if you accelerate past 30mph the truck goes to 3rd gear but do not exceed 35mph the second you let off the accel. it shifts back to second. Am I hurting the transmission? One transmission shop that is reputable diagnosed problem to be tcm reflash had to be done. So I took it back to my dealer and they tried to reflash the tcm but no codes showed . They did reroute alternator wiring that they said has been a problem but did not solve the problem. I have spent $236. 00 on diagnosis to no avail. Help