Transmission temp problems while towing

[Nick Redmond]

Easiest way to check is to turn the AC on, the fan should turn on shortly after.

Are you tuned at all? The fan won't come on unless the coolant temp gets to 220 with the AC off on the stock tune.

Personally I would mount a secondary cooler below the factory cooler which is the top 1/3 of the condenser/trans cooler assembly, and have the return line from the factory cooler feed the inlet of the secondary cooler. That way you get double the cooling. Only thing to watch out for is reducing fluid flow too much so make sure it's a high flow cooler or a relatively small cooler. You can get one with a fan but that's more work to install, more to go wrong in the future, etc.

Even with your setup, 190 is way too hot for normal driving. Something is definitely impeding fluid cooling because I towed around 4000lbs up the Ike Gauntlet with the truck loaded up as well and my trans hit 175 for about 5 mins before cooling down to 140 pretty quick when the road leveled out.

Keep us updated[emoji106]

I do have a diablo trinity T2 tuner on it I’m running the 87 octane tune I’ve also tried changing the temp where the fan comes on and it will delay it getting hot but will eventually get to 190-210 with about 1hr of driving. Another stupid question I have is I was going to order a deeper pan so I got the number off the trans and looked it up to make sure I get the right pan and from the sticker on the transmission it’s showing it’s a 66rfe. I’m the second owner and all I know about the previous owner is it was custom ordered from the factory. So I’m wondering if it came from the factory like that or if it’s been swapped or if its just not pulling up right. I know the 66rfe was in some 2500 trucks but never heard of one being in a 1500


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[rwreuter]

Hello everyone. I’ve got a 2012 ram 1500 5.7hemi with the 6speed trans crew cab 4x4 longhorn trim package with a 4in lift and 35in tires. I’m having problems with transmission temps when towing heavy loads in the mountains. On flat roads the temp stays around 190 but as soon as I get into the mountains the temp skyrockets. I’ve seen the temp go from 190 to 260 within a mile before I had to pull off the road. So my question Is does these trucks have a weak cooling system or do I have other problems like a clogged line or cooler? Or would I do better to put a bigger cooler with a fan that I can turn on with a switch? Any advice would be appreciated In a couple weeks I’ll be pulling a 12000lb trailer on a 6 hr round trip and 1hr of that is going trough mountains and rough terrain so I need to figure something out before then. BTW the reason I posted in the diy area is because it says I don’t have permission to post under anything else.


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Do you have the factory tow package with a transmission cooler?

 

[C Rogers]

My 2016 1500 shows at trans temp pf 244 while normal highway driving while not towing, had my mechanic hit it with a temp gun and temp was 177 when truck said 244. Dealer won't even look into it since no indicator lights are on. They told me that it's normal if no lights are coming on saying otherwise. This was after having the tranny changed under warranty due to a hard shift.

 

[Burla]

My 2016 1500 shows at trans temp pf 244 while normal highway driving while not towing, had my mechanic hit it with a temp gun and temp was 177 when truck said 244. Dealer won't even look into it since no indicator lights are on. They told me that it's normal if no lights are coming on saying otherwise. This was after having the tranny changed under warranty due to a hard shift.

Were those same temps happening when transmission was changed? The fluid in the 8 speed can handle higher temps and you can even add a different fluid that can handle higher temps, as a matter of fact these fluids don't break down under heat like dino oils. You can see your fluid operates in that range, and the esters can go 40f higher, that would be Redline d6. But, you might even consider redline c+ as it is slightly thicker, so if your truck is always that hot, this would make sense if you are out of warranty. They mechanically heat your transmission, part of CAFE agenda, and research if you can get that out of your truck, it will solve your issues. Or maybe research a better transmission cooler, and as long as you are running this hot, maybe do your own fluid changes more often, like in the 50k mile range. It is a pain to set the fluid level after a change, but just take your time and do it right. Do you have extended warranty?

 

[Nick Redmond]

My 2016 1500 shows at trans temp pf 244 while normal highway driving while not towing, had my mechanic hit it with a temp gun and temp was 177 when truck said 244. Dealer won't even look into it since no indicator lights are on. They told me that it's normal if no lights are coming on saying otherwise. This was after having the tranny changed under warranty due to a hard shift.

I don’t know if your trucks got it or not but from what I’ve researched some had a thermal bypass valve that are known to fail and cook transmissions. Mine doesn’t have it but when I was having problems with mine I cleaned the cooler fins and washed a lot of mud and dust buildup out and it’s been fine since and I recently towed a 6500lb trailer 12hrs straight on the interstate with the cruise set on 90mph and temps never exceeded 169. I’d look and see if you have that TBV and if so if it was my truck I’d delete that valve. It’s purpose is to warm the fluid up to running temp to increase gas mileage but I’d rather get a little worse gas mileage and extend the life of the transmission


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