O/D on or off when driving down the highway

[RVER]

I have always wondered when to use O/D and not to use it. I have a car, truck and MH. Today I found I drove on the highway for about 60 or so minutes with the O/D OFF. I wonder when it is appropriate to use it ON and when OFF. I do not pull a car yet.
How about on my truck, when to put O/D on and off?
Thanks in advance.

[westend]

Thanks, did I do damage to drive with it off?

No. The vehicle could be driven for it's entire life with OD off.

[RVER]

Thanks, did I do damage to drive with it off? I will leave on now that I know. NEW rig to me so getting used to it and did not know it had the on and off switch for O/D. LOTS to learn.

[nineoaks2004]

JIMNLIN wrote:
When my trannies TC clutch runs a lot unlocked or the tranny shifts up and down a lot I take it out of OD. Works with the car or my trucks.

This is the same thing I do. When it starts shifting back and forth I turn OD off, Ford recommends turning it off when towing, but on flat land I leave mine on, better gas mileage.

[Sam_Spade]

With "normal" driving, leave it ON.
It will switch itself OFF when it needs too (downshift).

If that happens too often for your comfort....or you know you will be pulling a big load or fighting a lot of wind or mountains, turn it OFF.

[JIMNLIN]

When my trannies TC clutch runs a lot unlocked or the tranny shifts up and down a lot I take it out of OD. Works with the car or my trucks.