Using "Overdrive" when hauling TC?

BMW442 wrote:
BTW - Our trip is going to be through the Blue Ridge Parkway and Great Smoky Mountains so I'm assuming there will be some elevation changes to deal with.

If you were going from Tennessee to North Carolina through the Great Smoky Mountains National Park, you will not need to worry about OD. Most likely you will never get out of 2nd or 3rd gear. Quite the climb. Going the other way, just don't burn up your brakes.

I let the computer do the job, only if its confused do I hit tow/haul or turn off OD. Enjoy the trip. How about some pictures when you return? :)

Thanks everybody

The camper dry weight is only 740# so I think even loaded with all our gear it should be totally fine. Also we are doing it extra low-budget/lightweight style with no battery, no 20# propane tank, and just the 5 gal water tank.

My mechanic advised turning off the OD if going up a steep hill, but otherwise just keep an eye on the RPM and adjust if needed.

billyg thanks for the heads up on the rally. We are hoping to leave Mass on the 6th and do a few nights at Shenandoah NP before heading to the Smokies. If we make it to Gatlinburg before the 10th we'll try to come thru!

I turn mine off to control downhill speed sometimes. Most of the time it doesn't make any difference with the gearing and power that I have otherwise.

That's an "old trucks tale"... Errr "Old Wives Tale". I had an older ford F150, and by older I mean 80's, not '01, before they were computer controlled.

Yes-- on older non-computer trucks you could overheat the tranny by towing in OD. I did... Didn't know any better back then, and was hauling a UHaul trailer over the mountain passes and I had tranny overtemp problems. The factory tranny cooler was not big enough, and there was no computer telling it that "it should" shift down--and of course the driver didn't either.

Now a days, the computer decides torque needed vs. throttle position much more efficiently, and the tranny coolers are larger.

For me, it is pretty simple. OD on probably would not hurt the transmission unless heavy load, especially up hill. OD off will not hurt the transmission period. Another thought to ponder is the RPM the engine is the most efficient, not for MPG, but pulling a hill. On my truck, the computer does not do as good of a job as I can just by pushing the button to turn off the OD.

On transmission temperature, I have two temp gauges. One is in the pan and one is in the line as the fluid leaves the torque converter going to the cooler. Pulling a steep hill, there can be a major difference in temps between the two. Using reverse for long periods of time is a real killer on fluid temps. Regardless of how much cooling you have, the pan temp can be normal and the torque converter dangerously hot. That heat started in the transmission, after the fluid left the pan with normal temps. My point is, you can ruin a transmission even with additional coolers. If your transmission pan has normal temps, additional coolers do nothing other than slow the warm up of the transmission fluid. Simply stated, why add cooler to a transmission that has normal temp in the pan?

Wayne

Golden_HVAC wrote:
Truck camper with a F-150? Passenger car tires too?

It's a, F150 "HD" 7700lb GVWR truck, so let's give the OP the benefit of the doubt, okay?

We have no idea what kind of camper he is hauling with it AFAICT, and it could very easily be something around 2000lbs loaded, which is perfectly safe in a truck like that.

Hi Having a smaller truck I learned real quick to turn the OD off. Our first trip to pick up the camper my transmission shifted up and down all the way home. I now drive all the time with the OD off. My engine RPM's are about 2800 @ 60 MPH. The engine now has enough torque for the grades and the engine slows us down. My MPG is about 12 which I think would be worse if I had to keep the pedal to the metal to maintain speed. If you will be in the area of Gatlinburg TENN stop in at the rally Nov 7-10. Bill

I would personally add an oversized transmission cooler and a trans temp gauge. I did and it has saved me from frying my E40D a couple of times. It also lets you know how hard your trans is laboring. Find out the optimum temp range for your trans and if the temp gauge starts wandering past that temp, disengage the overdrive. My 2 cents worth.

OD disengaged is essentially an OD lockout or prevents the transmission from shifting to the next higher gear. If you are pedaling a bike up a hill, you don't shift into a higher gear. The question becomes, "how big of a hill do I make that call on?"