Transmission Temp What Temp Is Optimal

96chevy7.4L · October 4, 2008

Hi guys I have made posts before but this is different. I have a 99 chevrolet C3500 7.4L vortec and 4L80E transmission. I added a Derale cooling tube pan which added 3 quarts to the pan. Also a 24,000 GVW cooler. My trans temp. gauge runs 150-170 with my 28ft flatbed gooseneck trailer on it with my kubota tractor. My question is......is it cool enough. I was going to add a transgo shift kit. Any thoughts on doing this. I have the superchips max tune in it on towing performance. I bumped up the trans pressure and the shift points in the programmer to get clean firm shifts. Run premium gas and octane boost. My truck runs strong. Any thoughts ideas or suggestions appreciated.

Zembonez · October 4, 2008

I'd say 150-170 is awesome. Mine runs that or higher just cruising without a load. Under 200 seems to be the consensus in here. Obviously well under is good.

96chevy7.4L · October 4, 2008

I have a 180 degree thermostat in the truck but you think 150-170 is awesome. Just a heads up one of the Derale cooling tube pans dropped the fluid temp 30 degrees. The cooling tubes go through the center of the pan and as the air passes under the truck air passes through those tubes and cools the fluid. In addition to the cooler that you already have. Plus the pan adds 3 quarts more fluid capacity. Check them out they are awesome.

merlin5577 · October 4, 2008

Hi guys I have made posts before but this is different. I have a 99 chevrolet C3500 7.4L vortec and 4L80E transmission. I added a Derale cooling tube pan which added 3 quarts to the pan. Also a 24,000 GVW cooler. My trans temp. gauge runs 150-170 with my 28ft flatbed gooseneck trailer on it with my kubota tractor. My question is......is it cool enough. I was going to add a transgo shift kit. Any thoughts on doing this. I have the superchips max tune in it on towing performance. I bumped up the trans pressure and the shift points in the programmer to get clean firm shifts. Run premium gas and octane boost. My truck runs strong. Any thoughts ideas or suggestions appreciated.

I agree with Zembonez. 150-170 while towing is awesome. Anything under 200 is acceptable. The higher you go above 200, the more damage you risk. Anything over 250 for more then a minute or two and I would change the fluid & filter. The highest I have ever seen my truck (Silverado) get is 190* with 2K lbs of wood in the back. Sounds like you set up your truck perfectly.

spiritrider1100 · November 21, 2008

Reposted From TCI Website

There's More To Coolers Than You Think:It's no secret that heat kills automatic transmissions. And in high-performance street-strip applications, the problem is especially acute. Small diameter torque converters coupled with stop-and-go traffic greatly increase the heat level in an automatic transmission. In most cases, the extra performance heat under the hood can have the same effect as heavy loads, trailer towing and desert conditions.

How hot is too hot? The ideal operating temperature for automatic transmission fluid is between 175 and 225° F. At approximately 240° F, important additives in the ATF begin to cook. The result is the formation of varnish inside the transmission. At approximately 260° F, internal transmission seals (which are typically manufactured from a polyacrylate material) begin to harden. The end results are leaks, both internal and external, simply because the seals lose their elasticity. At approximately 295° F, transmission clutch plates begin to slip because the oil is breaking down further. At approximately 315° F, seals and clutches effectively burn out. Carbon forms in the oil and for all intents and purposes, the transmission is junk. Just for your information, a typical transmission will die within 2000 miles if subjected to 300° F+ heat.[/size][/font]