Tow with O/D on or off? And what about downshifting?

[kamp k]

Originally Posted by Crusader

X2

X3. I use tow/haul button everytime my trailer is hitched to my truck, unless I am only moving the trailer around in my yard or driveway.

[Bunkfamily]

to the original poster, You are completely correct. The tranny will want to be in drive, not OD on grades and in some headwinds. I have gotten to the point of subconscious button pushing, when approching a hill, when the truck starts loosing speed, when slowing to exit a highway (will slow you down nicely) or when converter keeps unlocking. You never want to shift at full throttle if you can help it so pre-emptive shifting will do alot for the life of your tranny

[Bunkfamily]

Originally Posted by f1100turbo

As long as were talking fleet I might as well hi jack this puppy
1 2007 gmc 1500 4x4 tow haul
1 2005 Chevy 2500 hd tow haul
2 2001 Chevy 2500 hd tow haul
2 1993 f250 non turbos
2 1996 k2500
1 1993 f350
2 2003 f250 turbos
1 1989 c2500
1 1995 c1500
1 1998 r2500

1 1993 f250 7.3
1 1996 Bronco 5.8
1 1996 f450 7.3 dump
1 1996 f350 7.3 dump
4 1997 f350 7.3
1 1999 f250 5.4
1 1999 f350 7.3
1 1999 f350 6.8 4dr dually
1 2000 f350 7.3
3 2004 f350 6.0
1 2004 f350 6.0 dump
1 2004 f550 6.0 dump
1 2005 f150 5.4
2 2005 f350 6.0
2 2006 f350 6.0
1 2006 f350 6.0 dump
1 2006 f350 6.0 4dr dually
1 2010 f350 6.4 harley
1 2004 dodge durango
1 2008 ford expedition

[Sgt. Schultz]

OP my guess is you have the 4R70w transmission - Ford AOD transmission - Wikipedia, the free encyclopedia & TCCoA Tech Articles - biggest thing IMHO is trans temp if you don't have a cooler you should look at getting one, if the fluid is 10 years old you may want to consider getting it changed (not to close to trip time though) with regards to OD on or off the Fords towing guide state:
"Driving with an Automatic Overdrive
Transmission
• With certain car and compact truck
automatic overdrive transmissions, towing
– especially in hilly areas – may result in
excessive shifting between overdrive and
the next lower gear.
• If this occurs, it is recommended that the
overdrive gear be locked out to eliminate
the condition and provide steadier
performance (see your vehicle’s Owner
Guide for information).
• When there is no excessive shifting, use the
overdrive gear for optimum fuel economy.
• Overdrive also may be locked out to
obtain engine braking on downgrades."
From https://www.fleet.ford.com/showroom/...ering_tips.pdf

[JFM-jr]

Overdrive is not a towing gear(s) and in most cases is weaker. The best gear for towing is 3rd gear wich in most cases is 1:1 ratio and you want the converter to lock up. When the converter is unlocked there is some slippage wich decreases effeciency and increases heat. Maybe on some of these newer 6 speed transmissions it's different. On my 04 Ram the engineers at Dodge for some ungodly known reason decided to not allow the driver to choose 3rd gear with the column shifter. I have 1,2 and D. I can press the tow/haul button but even then it only locks out 5th gear and still allows the trans to shift to 4th (Again NOT a towing gear). It only results in a mere 200rpm drop. On later year Ram you can press the tow haul button twice once locks out 5th the second press locks out fourth as well leaving you in 3rd gear (Yaay Dodge you woke up).