Towing in overdrive - bad??

[towmysho]

I have a '97 F350 OBS automatic (stock E40D) w/ 4.10's and 35" tires with the manual torque converter lock mod. Also has 3" DP, 4" exhaust, chip, intake, and gauges..

Last weekend I towed my trailer+race car (5k total load). The owners manual recommends against towing in overdrive, but the PSD didn't seem to have a problem with it, even with the torque converter locked. She would pull uphill in overdrive without breaking a sweat, and do 70 on flat land like it was nothing. EGT's peaked at 1000 only when going uphill (in OD).

So am I doing damage to the tranny by towing in overdrive, given that this really isn't that heavy of a load? With the TCC locked, tranny temps never got higher than 150.

[4everlearning]

The main reason it is not recamended to tow in OD is, because of the constant down and upshifting of the trans to maintain speed. this causes heat in the trans and heat is an autos worste enemy.

[6.0 paul]

I always tow in OD, the only exception is in hilly areas where the trans shifts alot, then I take it out. Never a problem in a ford.

[willholl79]

I know what you mean. If I didn't pull in overdrive the rpms would be way up to maintain 65 to 70 mile an hour. I willl take it out of overdrive when starting off uphill loaded. Then when speeds and rpms are up i will shift into overdrive. Like was said above.....keep it from shifting in and out of overdrive.

[Gixxer]

In my 02 F250 I pull in OD quite often. However, it is fairly flat where I live. When it gets hilly I take it out of OD even though I've never seen the transmission begin to heat up.

[Farmboy444]

I pull in OD unless its town where i know itll shift into OD but then back down or in hills other than that sometimes i turn the OD off and let them rpms get a little higher then turn the OD on and let it shift in. Under a heavy load that seems to work the best to keep temps lower

[Triflex]

Me neither, I go 70 all day pulling a 12000 lb T. trl. in OD. No problem.