New to this particular diesel forum. I recently had to have my transmission rebuilt due to overheating while towing 5'er to camp site (and I already had the 6.0 cooler). Did the same trip post rebuild (only difference is now I have a Hydra with Heavy tow tune and deep transmission pan which holds 7 extra quarts) and was still getting hotter than I would like.

Details is I tow my 5th wheel toy hauler up a long, steady grade dirt road to get to camp site. It is very slow going up this dirt road (less than 10 mph I'm sure). This hill and particular towing situation is killing my transmission. My last trip (post rebuild) I stopped 3 times on the hill to let my transmission cool down (because I wasn't making the same mistake of letting it overheat again like the first time).

So I'm looking for towing techniques for my particular situation to aid in helping keep the transmission cooler (so I'm not contributing to the problem)? Do I tow it in 2nd gear, 1st gear, leave in drive alone? Tow it in 4x4? Any help in this matter would be appreciated......

 

I see you already have a 6.0 cooler. What is temp is to hot?

 

He has a 6.0 transcooler already, leave it in D and put in 4x4 hi should help.

 

Also what year is your truck? Early 99 thru early 00 most trucks were not equiped with a radiator cooler. You can buy the cooling lines thru ford you will aslo need a new radiator that has the transcooler in it.

 

I'm trying to edit my signature to include details about my truck, but I don't see a signature option under User CP?

I had the oem Ford 31 row cooler prior to the transmission overheat. After this last trip where to me the transmission was getting too hot for my liking I started getting desperate and am looking for fixes, upgrades etc. I now have a new Mishimoto cooler, but have not made the same trip since doing that. Doing it again here in a couple weeks, and need any pointers I can get.

As far as temps go, the first trip was too hot as it got over 240 degrees and puked the fluid. This last trip (post rebuild) I want to say I saw it get close to 210 degrees, but I pulled over 3 times to let it cool since I wasn't taking any chances this time. So I don't know what it would have gotten to without stopping.

I've already done the flow tests, and cooler flow is fine (well over the 32 oz in 15 seconds).

 

If the speed is 10MPH or less why not put it in 4 wheel low and just cruise?

 

This is why I'm asking the question. I don't want to be doing something that is "contributing" to the extra heat. I'm not well versed on the drive train on these things (but learning more and more as I read), but didn't know if running in 4x4, 4x4 low, 1st gear, 2nd gear, or Drive would add to the heat problem.

One more detail on the road I drive. It is a smooth dirt road (not climbing over boulders, rocks, etc). It is just a long, steady grade which is slow going pulling the 5th wheel toyhauler. I want to say the toyhauler is around 8700 lbs dry and "rated" up to 14k loaded (although I don't believe I have it at max).

 

I'm not finding a signature option under user CP. So here is the details for now until I figure that out. I have a 2002 F250 CC 4x4 w/ 7.3 diesel (so has the transmission radiator cooling option). Stock transmission prior, and now mildly rebuilt transmission with updated transmission parts and Transgo Tugger valve body, billet tripple disc converter, and new deep AFE transmission pan which holds 7 extra quarts with upgraded 2008 style transmission filter that has filter media and not just rock catcher screen. I now have a Mishimoto 6.0 liter transmission cooler (prior I had the oem Ford 31 row 6.0 cooler). And post rebuild I now have a Hydra programmer post transmission rebuild (not prior when transmission overheated).

Flow tested the original 6.0 cooler and new Mishimoto cooler, and both flows were over the 32oz in 15 seconds spec.

I'd like to make it up this hill without having to stop....

Edit: I forgot to add that my truck has a 2.5" leveling kit and F350 blocks in the rear and I'm running the equivalent of 34" tires and custom aluminum wheels. If I knew then that I would eventually end up with a 32ft 5th wheel, I probably would have gone with a little smaller tires. I know this setup definitely doesn't help with my towing or gas mileage for that matter.

 

 

 

I've made this trip 3 times so far. Two prior with stock transmission, and 3rd since the transmission rebuild, new upgraded pan and Hydra tow tune. I towed the first time up the hill in the fall of last year. So outside temperature wasn't too hot. I don't recall what my trans temp was on that first trip, however, it wasn't high enough to give me concern. So that is why I don't recall, but never stopped once, and I think I had the thing just in Drive the whole time. Second trip was only two weeks later from the first (so same outside temp conditions), and this is when it overheated. And I remember watching the temp get hotter, and dropping the gear into 2nd I believe. So not knowing the drive train on these very well, I was wondering if dropping it into 2nd added more heat?. 3rd trip was spring of this year (so not too hot outside) and I stopped 2-3 times (can't recall now) since I saw temps hitting 200 degree mark and climbing (if memory serves me well I believe I saw temp up to 210 degrees but I stopped). Wasn't testing the limits this time.

I want to do it right the 4th time (and it would be nice to not have to stop on the hill to cool down if possible), so any consensus on what the best method to drive in would be appreciated. Thanks for the replies so far. I'll take any good advice.

 

"low range to keep rpm up that will keep fan turning faster"

The fan has a thermostatically controlled clutch system. It could be that the clutch is not working properly and fully engaging to drive the fan when needed.

 

There was/is a mod in which people were using for backing big trailers in to parking spots. The mod would allow 4low but not lock the front hubs. ( for those with the auto hubs)

If the road is dirt, I'd just go 4low and get after it.

 

My granddad has a mod like that for pulling his big fifth wheel around the hills and barn at his house. I can't remember exactly the details, but he rigged up a switch in the cab where once you engage 4x4 Lo it will block the vacuum line and not lock the front hubs. This way you get the extra low range, but only the rear wheels driving making it easy to maneuver.

 

How long is a "long steady grade"? Is it 1/2 mile, 2 miles?

Either way, if I were in your situation and not in a hurry to get up the hill I would stop at the bottom, put it in 4 LO and let it crawl up the hill. Once at the top and sitting on level ground, shift it back into 2WD and go about your business.

Dan V is mentioning the 2WD LO mod. I have done a video on how to accomplish this via a switch in the cab and it works well. If you wanted to just pull the 3 wire connector on the solenoid that would accomplish the same thing though. Below is the video.