I have a 2001 V10 F250 Lariat Crew Cab 4X4, purchased used a couple of years ago. Don't know what axle ratio it is, turns about 2000 rpm at 70 mph with LT 285 75 16's. Bought it because I was planning to downsize my boat to one I could trailer, but ended up keeping the old boat, so I've never towed anything with it until this week. Daughter is into the horse thing, so last week I purchased a Sundowner 2 horse trailer, around 2800 lbs empty, so we could take her and the horse to a riding clinic next week about 300 miles away. We live in LA (Lower Alabama), and will be going to Hamilton, GA. No real steep grades, mostly pretty flat with rolling hills. I bought the trailer from a dealer about 70 miles away, so the only towing I've done with it is to pull it home over level interstate. Obviously the truck had no problem pulling the empty trailer, ran 70 mph with OD engaged, and it only shifted out of OD a few times going over overpasses. I didn't notice the torque converter hunting.

Finally, for the question: The trailer will be around 4000 lbs loaded. Should I keep the transmission locked out of OD even on level ground? It turns about 2800 at 70 mph, and I guess it just sounds a little busy since I'm used to around 2000. I got about 11 mpg towing it with OD engaged, closer to 10 mpg with it locked out. Will certainly put up with a bit more noise and a bit lower fuel economy if running in OD will trash the transmission. Anything else I need to be aware of? Thanks

 

i would leave o/d on when on flat ground and turn it off going thru hills

 

Leave the OD engaged but only if you're on flat runs for awhile. Once you start getting into some rolling hills no matter how slight, take it out of OD.

 

Drive in the tallest gear that the torque converter will stay locked.

 

Thanks for the replies. Just got back, didn't take long to decide just to lock out OD since it would kick down at the slightest grade. Apparently the additional couple of thousand pounds of horse, tack, passengers and luggage was a bit much for anything but level road. Badly underestimated fuel consumption; 7.7 mpg on the way up (net uphill), and 8.7 mpg coming back. Pulled it just fine, only kicked down another gear once on a steep uphill. Thanks again.

 

I would not. 2000 RPM at 70 is too tall and will put a lot of strain on tranny. 2800 RPM will not hurt a thing and it is likely MPG will be better too. Sounds like you have a 3.73 gear which is a bad combo for towing in OD even with a V10 You will have to pay for the tranny if you have problems from towing in OD, not the posters that tell you it is okay.

 

I agree with snowman, I have an 03' F250 V10 that when hitched to the camper & boat I'm grossing around 17k, aprox. 10k for the trailors and 7k for the truck. don't under estimate your V10 as I was disappointed with my V10 the first time I towed. it was only 5k pounds and it seemed like it was a dog for that amount of weight. So I was extremely suprised when I grossed 17k lbs and it towed not much different than the 5k lb trailor, go figure. I also have 3.73s but like snowman said just lock it out and let her buck. you can probably do OD on the flats but as soon as you see a hill you'll be downshift or replacing that 4R100. Don't be afraid of revin the V10, the Mod motors love rpms, when I get into steep grades I'll see 4200rpms at around 70mph but I don't slow down like alot of the other guys!! I won't lie I can't break 9mpg when towing the boat and camper but if you wan to play you gotta pay! have fun and good luck with your v10. and by the way if you want to see a large towing improvement switch the gears over to 4.30s and it tow like an animal.

 

Yes a V10 with a 4.30 is a towing beast with stock tires!

 

I watched the trans temp with and without OD locked out when towing an 8K trailer and found little difference in heat build up.

Many folks over 50 will tell you to lockout OD all the time when towing because the older vehicles weren't able to cope with the heat when towing in OD. Todays transmissions do better.

Ford and others say you should be ok to run with OD on unless the trans is hunting on the hills. I am in this camp...

 

I think that is age discrimination and a uncalled for comment. What you do not see on your temp gauge it the much higher input torque and OD clutch loads and the higher engine cylinder pressure and bearing loads to make the same HP to move the load at a lower RPM. THe HP requirements to move the load do not change with engine RPM and the negine has to work harder to make it at a lower RPM.

 

I meant no disrespect in the age comment. I am sorry if you took it differently than I intended. I only wanted to point out that running sans OD was in years past a valid and important recommendation that was held to by people who were driving vehicles during a time when OD first came out in automatic transmissions. For today's transmissions this recommendation is not as common. I am 40 and started driving when this recommendation was starting to evolve due to transmission design changes. Having spent years as a service writer, one finds patterns in behavior, some related to age.

Since you seem to know more about transmissions than I, maybe you can answer this question. Why would Ford recommend the use of OD, as I have recommended, when they are responsible for maintaining the warranty of their transmissions? Wouldn't it stand to reason that they would want to save money on warranty repairs by suggesting we tow w/o overdrive on?

I am no engineer, but if Ford says it's ok, why wouldn't I trust their judgment?

 

Ok, I talked to a buddy of mine that works at the ford transmission plant here. He says never pull in OD. There was a bunch of technical stuff that followed his comment which I'm unable to reproduce.....Anyway, basically you shorten the life of your transmission everytime you tow with OD locked in.

 

Personaaly I have no problems with using OD towing IF you have the proper axle ratios for the load. Ford recommands it because GM does and they all have to compete and unless you abuse it padly it will last thrugh warranty period, it is what is left after warranty is the issue and towing in OD with a 4.30 is a LOT easier on tranny than towing with a 3.73 in OD. Myself, I like a deep enough axle ratio that OD is more usable as a extra gear (4th, 5th or 6th depending on tranny) and not just as a tall gear that has limited real world use.

 

I guess I will toss my owners manual in the trash when I leave work. It obviously isn't worth the paper it's printed on, it can't be trusted.

 

My last trip to Myrtle Beach I towed with OD locked in on the way down. Of course I took it out once I got to some hilly terrain. On the way back I towed with OD out the whole time. Difference in gas mileage, 1 to 1.5 mpg. Having the power when I need it and saving the life of my tranny, priceless......

I do however leave OD locked in on flat terrain with the cruise set.