sammyg

I am going to be pulling a camping trailer with my 07 Supercrew 4x4.The truck has a 5.4 engine ,auto transmission and 3.55 gearing.The camper is about 21 feet in length and according to the tag on it, it weighs 3459 lbs.What I've found according to my owners manual is that my truck is rated to handle this size trailer but cannot find anything in there about the O/D on the transmission. Should I tow this with the O/D in the transmission turned off or should I leave it on.Don't want to take a chance of damaging anything.

mike243

Put it into the tow/haul mode and dont worry about getting another mpg.that will cut down shifting and keep it cooler imo

Tachdriver

Agree, put it in tow/haul mode. Your trailer probably weighs more than what that sticker says. Once you add kitchen, bath, bed room provisions plus any tools, jack pads etc your weight will increase. Mine went up about 1000 pounds but I do have ice makers and stuff that others do not carry.

Be interesting to get it weighed at a weigh station.

JJM

There is no tow/haul on this year.

Yes, tow with O/D off.

lewisra

I was thinking maybe it didn't have tow/haul.


As far as O/D, I would leave it on in areas that it won't keep shifting up and down.

smokeywren

Depends. Leave it on overdrive unless the transmission "hunts" between gears on uphill grades. If it downshifts and then doesn't upshift again while on a grade, then leave the overdrive on. If it downshifts for uphill grades then upshifts for downhill grades, leave it in overdrive unless you're in rolling hills where it is constantly upshifting and downshifting as you climb hills then go down the other side. IOW, let the computer decide which gear you need to be in, except when the terrain results in constant shifting. Constant shifting heats up the ATF, and too-hot ATF is a tranny killer.


For example, I normally leave mine in overdrive all the time. But in the hills between Austin and Brady, I kill the overdrive until I get out of the hills.


The tranny killer is heat. If you tow without a good tranny temp gauge, you're asking for a burned-up tranny. The red line is 225° sump temp, or about 235° on a scanguage that uses the OEM tranny temp sender which is in the tranny valve body and not the sump. If your Ford has a factory analog tranny temp gauge, it appears to be an analog gauge. But it's not - it's an idiot gauge. White or green means go, but the instant it jumps into the yellow the tranny is too hot, so you should pull over and stop, shift into neutral or park, and elevate the idle to about 1,200 RPM until the gauge falls back into the "normal" zone. The red zone means your tranny is probably already toast, so good luck in making it to the next town. If your Ford has a digital tranny temp gauge in the dash display, then use 235° as your red line.


If you install an aftermarket tranny temp gauge, DO NOT install the sender in a tranny cooler line. The hot line going to the cooler(s) gets way over 235°, but that's not a problem. The cold (return) line from the cooler(s) has much cooler ATF than sump temp. so that won't tell you anything about sump temp.


If your Ford doesn't have at least the regular towing package, then you need to install a big oil-to-air tranny cooler in addition to the tranny temp gauge.


A lot of Ford automagic trannys have a port that shows close to sump temp. The 4R100 and 4R80 trannys have that port. But if you don't know how to install the sender in a port that shows sump temp, or if your tranny doesn't have that port, then install a threaded bung in the tranny pan and install the sender in that bung. Then watch that gauge closely and shutter down when you get close to the 225° red line.

sammyg

Thanks guys,I really appreciate the help and advice.