Transmission temps: How hot is too hot?

[oreogaborio]

I understand that as temp increases the transmission fluid lifespan decreases, but how hot is too hot?



Reason I ask is last week I was in upstate NY, got caught off guard by the terrain and had to climb a freakin mountain with my race trailer (4-5k lbs?). I was in 1st gear the way up and 1st gear all the way down... transmission temp, according to my Bully Dog GT reached 248*F and I was crapping myself. Truck seemed to handle it okay but I was awfully nervous seeing those temps.


I performed the bypass when I purchased the truck at 84k miles and I RARELY ever see trans temps above 220*F when towing but this last trip has me wondering if I should install an additional trans cooler or electric fan or both.

Last trans flulid change was about 40k miles ago.... bout to change it out again now that I'm towing heavy.

[disallow]

over 240 but under 275 is ok for short periods.

[oreogaborio]

Beautiful. I searched around but couldn't find an answer I was satisfied with.

I'll skip the aux cooler & spend my money on fluid, then.

Thanks, man

[smj999smj]

Try this page. It should answer your question adequately:

http://www.digi-panel.com/trannyoil.htm

[oreogaborio]

Beautiful. Thanks!