I'm on the road to go pick up a load of furniture and the transmission temp shot up to 250* with an ambient of 30*. The only thing I'm pulling is an empty trailer that weighs 3400 lbs. Does anybody have an idea of what would be.causing those kinds of temps? The gauge maxes out at 250* and it is pegged. The fluid does not appear to be burnt nor any excessive heat. Please help.

 

Maybe ground wire for gauge is loose and/sensor bad. Not sure if it'll help, but to feel the trans for warmth. 250* wud make case a tad warm

 

Case felt some warm, but not out of reason. What is bothering me, is the coolers for the trans are cool, not warm. Is there a chance the bypass valve would have messed up and could be.causing readings like those?

 

Cooler would be cold to the touch and the transmission just warm. 250 degrees would make you flinch pretty quick. It sounds like a wonky gauge.

 

Mike, my guess is the same as Timmys. If the by pass was the issue wouldn't the coolers be 30*, same as ambient ? If the case is just warm, than you should be ok. Maybe Mark will pick up on this and give some professional advice.
Jim

 

Thanks, just to be on the safe side, my dad is bringing the other truck. I'm go on with it and he's going to take the other one home

 

Had the same thing happen to me a few years ago in my old F250. I'm hours into a long drive down to SoCal and I see my trans temp gauge reading over 250* degrees. I pull over and let the truck idle for over 15 minutes without seeing a change in temp. I check the fluid and all seems ok. I shut the engine off and when I restarted, the gauge dropped back down into the normal temp range.

To this day, I have no idea why my gauge went cattywhompus.

Stewart

 

Same thing happens in the late model buses I drive up here, do a restart & all's well, who knows.....

 

don't mean to high jack but that is a lot of windows in your trailer my wife would love that. is it them same one both sides?

 

Update. Made it home about 11:00 last night with no further major problems out of the second truck other than changing the alternator. But, I've done that so many times I could probably do it in my sleep. Dad made it home in the other truck fine, although the gauge was still acting up. I'm going to take the gauge pillar apart this week and see what I can find out. I'll post an update when I do. Thanks to everyone who contributed.

 

Given that the trans was not hot to the touch and the gauge was apparently pegged, I would also look at the gauge and wiring first. But if the gauge checks out then the other symptoms (cold cooler, hot trans temp) are what you'd expect from a clogged cooler with the bypass doing it's job. Or a failed bypass. My two centavos.