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I didn't mean to step on any toes and I didn't say Labnerd was wrong I just said everything I read points to heat being the killer of your transmission not cold.
This trans reman site recommends an external cooler with a fan and goes on to say that he sees many 6R80 transmissions that are burnt up.
The thermostat in the 6R80 transmission opens at 170-180F. I have a scangauge attached all the time and as the temperature rises you can see a linear rise up to that point and then, depending on the outside temp, settles at 185-195 when not towing. That is with the normal, OEM cooler. The cooler itself is available from Rockauto for $50 or less. You could find a wrecked 09-14 truck and pull the lines and mount from it or buy some 1/2" ID transmission hose and set it up yourself. Less than $200 would build the complete system. I've added an external filter mount inline with the cooler for fun.
Lots of good info here, thanks to everyone that responded.
So turns out I can get an oem cooler outta a wrecked 09 in a junkyard for $40. If this somehow falls through I'll go with the aftermarket (oem) option stated above.
Looking into what's involved for the install I think I'll tackle it myself. One question though:
After the cooler and new lines are installed what is the best way to top up the tranny fluid? I know the dipstick and filler port is accessed underneath the truck and the transmission. I'm just wondering what the best way to go about it.
If you haven't had your transmission flushed I'd say wait to install it just before you get it done, that's what I did. The amount the cooler holds is negligible. That was one of my concerns as well and it turns out the cooler only added another 8oz or so of fluid, I checked prior to installing. The amount you lose by removing the old line is very very little and none will flow back out of the radiator when the hose is removed. My truck was cold when I did it also. I guess if you wanted to add some the easiest way might be to just fill the cooler after the lower line is installed with about 1/2 a quart.
Last edited by mk19; 02-04-2016 at 05:05 PM.
Reason: filling
If you are getting a cooler out of the boneyard, I'd highly recommend solvent flushing it and blowing it out with compressed air before installing it.
You top it off the same way you would with a conventional dipstick - warm with engine running. There's a dipstick attached to the fill plug. Remember that it takes Mercon LV, not conventional Mercon V.
01-26-2016 | 12:05 PM
