Mishimoto MMTC-RAM-03SL Trans Cooler, Ram 2500-5500 Cummins 2003-09, Silver

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"I don’t typically write reviews, but this cooler deserves one. I have a 06 3500 drw cummins with just shy of 1200 tq. I shredded my..."

17fireball

"I purchased this trans cooler for my 2003 Ram 3500 dually with 5.9 Cummins. I am upgrading this truck and equipping it to tow a..." "I purchased this trans cooler for my 2003 Ram 3500 dually with 5.9 Cummins. I am upgrading this truck and equipping it to tow a 14K fifth wheel trailer in the mountain west. I recently had the 48RE transmission overhauled and I wanted to protect it as much as possible from heat generated while towing a heavy load. First of all, the Mishimoto trans cooler looks to be of very high quality, especially when compared to the oem unit. It arrived in perfect condition. I unpacked it from a sturdy cardboard box with the unit completely encapsulated in closed cell foam- extremely robust packaging. All kit components were secured in sealed plastic bags. I watched the Mishimoto video(s) for installation of the cooler in the truck and for installing the thermostat delete. This is a very well engineered option that is provided to the buyer in the kit that allows the cooler thermostat to be eliminated depending upon the climate that the cooler is deployed in. The cooler is shipped with the thermostat installed. Getting to the oem cooler and removing it is straightforward with the steps outlined well in the video. The install instructions recommend splicing the supplied barbed fittings into both the oem feed and supply rubber trans cooler lines and securing them with the 4 supplied hose clamps. The oem feed line on my truck was already leaking from both of the crimped ferrules on each end of the rubber line which is attached to the steel line feed line coming from the transmission. I didn't want to plumb into an already suspect line so I removed the feed line at the fitting below the check (anti drainback) valve. I used a 7/8" open end wrench and a medium size crescent wrench to loosen this fitting and the whole line came right off. Since I wanted to reinstall the anti drainback valve, I cut the oem ferrule off of it with a Dremel tool and cut off wheel. I then realized that the Mishimoto supplied cooler line might be a little short to get neatly around the intercooler tube and onto the Mishimoto cooler inlet. So I took the check valve and fitting to a local hydraulic hose supply store and bought a 36" length of high temp hydraulic hose (trans cooler line is near impossible to find at retail) and had them crimp the assembly together with a ferrule. I then trimmed it a little to length and it worked great. I reattached the valve/hose assembly to the steel feed line and used the supplied hose clamp to attach the hose to the cooler inlet. On the return side, I used the splice method recommended in the factory install video. My main concern was that I was attaching the beautiful new Mishimoto cooler hose to my crusty 16 year old oem line which has been through countless heat cycles and was pretty hard and not nearly as flexible as new line. Well, the clamp on the oem hose side did not seal up initially and it leaked. This was probably my fault. Make sure you put the hose clamps 1/2" away from the shoulder on both sides of the barbed coupler because there is a taper that prevents full clamping force. I torqued the snot out of the hose clamp and got it to stop leaking- I think. My future plan is to remove the factory return line fitting at the steel line with a $12 AC/fuel line/trans cooler line removal kit that I purchased at Harbor Freight. It works great. Going to take that fitting back to my hose shop and buy another 36" of hose and get the ferrule installed. That way I have 2 lines with no splices to reduce the possibility of leaks. Finally- how does this cooler work? With Mishimoto cooler (with thermostat installed) and the truck at normal operating temperature (unloaded) and 68f ambient,I did a 35 mile run that combined some stop and go, 20 miles of interstate at 67 mph and some divided state highway with a significant uphill grade: I got a 160-169f trans temp reading from my Banks I-Dash gauge which reads temp in the transmission valve body. (Update: just duplicated the run I described with thermostat delete plug installed and the truck ran -20f degrees cooler. Additionally ambient temp was also hotter @75f. I plan to do more testing while towing my fifth wheel and also with the cooler thermostat delete plug installed. (Just completed a 300 mile round trip towing my 14k lb fifth wheel. Trans temp on I-15 in from Las Vegas to Mesquite, NV and return was 153 to 160 f. Running 65 mph avg. speed. Ambient temp was 70-75 f.) Although the Mishimoto trans cooler is not cheap, it is a beautifully designed and built part. I look at this purchase as less than 10% of the cost of my recent transmission rebuild. I believe this cooler is going to save my trans this Summer when I am towing that trailer up mountain grades. I am really impressed with this product and would recommend it to any Dodge Ram owner that asks his/her truck to work hard."

D.C.

"Super nice product! Works awesome on my 2005 Dodge Ram 2500 Cummins! Stage 3 Transmission so I am all set and Dino at 700 horse..."

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Mishimoto MMTC-RAM-03SL Trans Cooler, Ram 2500-5500 Cummins 2003-09, Silver

What Customers Say

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