Transmission Cooler

itsmeagain5789 · June 8, 2009

hey guys, i got a 93 c1500 with a 5.7L and i was just wondering how big of a transmission cooler I need if im going to tow 6500lb's with it. I am regearing to 3.73's sometime this week. i am also looking for some ideas on how to run the cooler lines. Right now, I have a hayden 678 mounted behind the grill for most flow, but I think I should have probably gone with a 679. What do you guys think? I have it going from the transmission, to radiator, to cooler, then back to the transmission. Any other ideas? also when im towing right now with my setup, the temperature gauge on the dash goes up about half way to 210 degrees. is this normal or is this a little too warm for the engine? thanks, give me all opinions because im going to be towing over a thousand miles this month through august, so I just want to make sure my truck is going to be able to handle it.

txab · June 8, 2009

I'd go with the 679. That should be 11" x 11" x 3/4" . Your fluid routing is fine. Trans to radiator to aux. cooler to trans will work. You don't say where you live, but if you live in cold climate for winter you might want to think about a thermostat for the cooler. Fluid that is too cold can affect trans operation

Check your fan clutch for proper operation. You want it working perfectly. I'd think with the 678 you shouldn't be running that high of trans temps. But with your current gearing you may be working the trans really hard while pulling. What kind of speeds are you towing at?

Another member reports towing 6500#'s in 95+ temps and running in the 160's for trans temp using the 11 x 11.

You might want to consider switching to synthetic fluid if you haven't already.

Trans cooler pic

A big thanks to Trey for all this info.

Mike G · June 8, 2009

also when im towing right now with my setup, the temperature gauge on the dash goes up about half way to 210 degrees. is this normal or is this a little too warm for the engine?

That would be the engine temp you are referencing, and not a trans temp gauge, correct? I would look into possibly pulling the thermostat cover and looking into replacing your t-stat. Has that been done recently? Sounds like it may be hanging up. You want the engine colling side up to shuff too.

--Mike

itsmeagain5789 · June 9, 2009

also when im towing right now with my setup, the temperature gauge on the dash goes up about half way to 210 degrees. is this normal or is this a little too warm for the engine?

That would be the engine temp you are referencing, and not a trans temp gauge, correct? I would look into possibly pulling the thermostat cover and looking into replacing your t-stat. Has that been done recently? Sounds like it may be hanging up. You want the engine colling side up to shuff too.

--Mike

yes that would be the engine temp. I have no idea what the trans is, since i haven't gotten a gauge yet. I will probably replace the thermostat also before my long tow trip.