O.K., here's the deal. Had this truck for a couple of years now. Had a DP Tuner, dual exhaust and gages on the pillar which include a pyrometer, transmission temp and turbo boost installed when I bought it. It had 195K on the clock and had the tranny rebuilt at 130K. Bought it to tow our 25' 5th wheel. Transmission does just fine pulling the trailer at highway speeds even up some pretty steep Idaho grades. Runs about 180 degrees towing.
Once a year I pull this trailer up to hunting camp, uphill for about 9 miles at 25mph max. The first time, towards the top, the temps got to about 240 and I shut it down and let it cool before continuing. Changed the fluid when I got back to town but it didn't smell burnt.
I figured it wasn't getting enough air across the cooler at that speed so I added a tranny cooler with thermostatically controlled fan which was rated to 30K motorhome.The next year it made no difference. I shut it down earlier but it was on it's way to 240 again.
It's been a great truck other than this issue. No fluid leaks at all and uses about a Qt. of oil in 5K
So, I figure a line is plugged or bypass malfunctioning? Do I need to take it to a good tranny shop to have it diagnosed or do you guys have any tricks?
I forgot to mention that when I bought the truck, I serviced the tranny,replaced the filter and replaced the in-line filter.
I found this with a search:
bmodel bmodel is offline
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Join Date: Feb 2008
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I might know whats your problem is!
The transmission cooler as they exit the transmission has a crossover tube with a check valve in the line, this is a bypass tube that ford installed to warm up the transmission quicker in the cold, the line has two banjo fittings on it, the tranny lines go into a fitting which screws into the banjo fittings, trust me if that line is there in your truck then replace it. The line is only $25.00-$30.00 from Ford, or you can eliminate it, this will most likely solve your problem! I put a transmission cooler for a 6.0 on my truck later which bolts right up to the stock location and you need to run 1/2 lines instead of 3/8 but my truck loaded does not get hot anymore it runs at about 150-180 in the summer towing! I overheated my transmission 2 or 3 times at 250-280 and she is still shifting fine, the r4100's can take the temperatures as long as they are not prolonged!
Think I'm on the right track?