transmission temps

[marc]

Here is my problem, I think. GCVW 21400#, massdiesel transmission line with temp sensor port. When towing my fiver and transmission is locked up either in 3rd or OD the temp stays between 145 and 180 depending on hills and air temp, however as soon as the transmission unlocks the temps climb to as much as 280 and as soon as the TC locks up again temp goes down. Fluid is stock and seems normal (not burned) What gives? Is this normal or do I have a problem?

 

[lmills]

That's a pretty good size load. I would say your numbers are probably pretty good. Remember when you take your measurements from the cooler line, you are getting them after they have been through the whole transmission and converter. If the converter is unlocked then it is slipping. So it will build more heat than when it is locked up. Also the cooler line will yield the highest temps. It will let you know what the fluid is being subjected to.