68RFE Transmission Oil Cooler

[RUSSELL5000]

This is a quick question for anyone expert in the 68RFE and/or experienced fourth generation folks.



I keep studying RV materials in order to educate myself in preparation for the summer 2014 Yellowstone/Grand Teton trip. One of the things I keep reading is to get an auxiliary transmission fluid cooler.



I added an aftermarket deep aluminum pan with cooling fins (PML from Geno’s) that added four quarts to the fluid capacity. In reading about the 68RFE it seems to me that I have done more than required to keep transmission fluid temperatires down.



My rig is in the signature – as best I can tell, running about 80% of rated ability of the truck.



Does anyone think there would be any benefit to the auxiliary transmission fluid cooler? It does not seem to me that there would be – but, I keep reading and hearing that there is. Am I missing something?



Thanks!

 

[Newt]

I tow ~15,500 with my 09. I've towed over Wolf Creek Pass with no transmission overheating problems. I use the EDGE CTS for gauges. Your trailer should be no problem at all, stone stock truck.

I've heard that the deep trans pans will add some rigidity to the 68RFE case. Which is not a bad thing.

Newt

 

[Jim W]

This is a quick question for anyone expert in the 68RFE and/or experienced fourth generation folks.

I keep studying RV materials in order to educate myself in preparation for the summer 2014 Yellowstone/Grand Teton trip. One of the things I keep reading is to get an auxiliary transmission fluid cooler.

I added an aftermarket deep aluminum pan with cooling fins (PML from Geno's) that added four quarts to the fluid capacity. In reading about the 68RFE it seems to me that I have done more than required to keep transmission fluid temperatires down.

My rig is in the signature - as best I can tell, running about 80% of rated ability of the truck.

Does anyone think there would be any benefit to the auxiliary transmission fluid cooler? It does not seem to me that there would be - but, I keep reading and hearing that there is. Am I missing something?

Thanks!

Russell;
I have towed out west twice and back east twice with no auxiliary transmission oil cooler with my 08 Ram equipped with the 68RFE auto. I do have the Mag-Hytec transmission oil pan and diff covers on my truck. The first trip out west was to SD and MT Rushmore. When we were driving on the Needles highway RT 87 I was using the engine brake to keep the speed in check without the trailer and the transmission temps did raise over 220F. It was then that I decided to install the Mag-Hytec oil pan. Since then I have never been over 200F with and without the trailer attach.

I have driven to Yellowstone and we were in Rocky Mountain National Park the same year with no overheating issues. I have also driven through the Smoky Mountains twice with no issues either. I am pulling a 318SAB Cougar 5th wheel and have been since 2010, my other 5er was a 270RKS Summit Ridge Ameri-Camp.

In my humble opinion you should not need any additional cooling with your deep transmission oil pan installed.

Jim W.

 

[RustyJC]

I tow a 16K GVWR 5th wheel with our 2011 Ram (see signature). It's absolutely stock. The highest transmission fluid temp I've ever seen on the EVIC was 212 degF on a long pull up the side of a mountain with continuous switchbacks which meant I almost never got out of 1st gear with the torque converter unlocked - a worst case condition for high transmission temps. Normal cruising on the Interstate when towing yields 160 - 170 degF transmission fluid temps.



Rusty

 

[RUSSELL5000]

Thanks much, guys. As always I learn mountains on this forum.



Sure is nice to take others experience than earn it with my own wallet!!!

 

[tommyturbo]

RUSSELL5000, Looks like you got some excellent replies. My experience with trans temps is only after the Mag-Hytec
installation. Gauges added after. Anyway, some towing temps: Cherokee #8000 TT towing LA CA to Tucson Az and
back across the desert around 170 deg. Borrago Springs CA to Temecula CA going West through switchbacks down to
24 MPH under 160 deg. Stayed locked up in 4th all the way up. Got up to 45 MPH at top each hill before the next switch
back. Southbound I-5 over the Gorman Pass set cruise @65MPH in 5th @ 2250 RPM. 150 deg. Stop and go LA traffic on CA CA101 toward Malibu around 200 deg. I agree with the other replies that you are safe without an extra cooler.
My two cents.
Tom

 

[RUSSELL5000]

Thanks, guys.



I towed for around six hours this weekened - taking my small boat to storage (4k trailer) and taking the boy scout troop to a camping weekend (5k trailer). Almost all interstate driving - some hills, but nothing over a 5% grade. The EVIC showed transmission fluid temperatures that were in the 130s in the morning when it was cool and 140s in the afternoon.



Seems ideal to me. I'll forgo the additional cooler.



Thanks.

 

[rscurtis]

Unlike trucks (and cars) in the old days, both of my Dodges had plenty of cooling capacity right from the factory.

 

[Gonzo 1066]

I have been impressed with how cool the transmission on my 2013 has been. 7000 miles of towing my horse trailer "toy hauler" and have only seen over 190 degrees once. (UPDATE now over 13,000 towing miles with the same low trans temps) The towing miles are all in the West, quite a few hot days, lots of 6-8% grades.

 

[RUSSELL5000]

Thought I'd post a follow-up. Took a nice vacation trip recently - went through West Virginia, quite a few grades ranging from 6% to 9%. The trailer in my signature is GVWR rated at 9,500 lbs.

Regardless of grade I never saw an EVIC fluid temperature of over 170 degrees, and ran at about 160 degrees when the outside temperature was in the middle 80's.

So, I think my rig set-up is fine, and expect long service from the 68FRE. The PML pan and lost of extra fluid appears to keep everything quite cool.

I was in a situation last year when I was going up a steep grade (between 9% and 11%) for a long distance at a very low speed, and so the torque converter could not lock up. The EVIC fluid temperature went to 210 degrees. I have not been in the situation since and the highest EVIC fluid temperature I have observed since then was 173 degrees.