4 Speed Over.D THM R2(4l80E)4-spd A\trans(MT1)

[Martin R]

I pull with brand knew 6.6' S where the rig does pretty much everything for you now i'm wondering when, if, don't, max weight, no load, up hill Should i drive in over drive. In need of a crash course if somebody has time. Thanks

[DaveBr]

Yes you can pull in overdrive. If you are going up steep grades turn off the cruise and let it go back into third then ease up on the throttle untill it goes into lock up.

[16gaSxS]

Yes you can pull in overdrive. If you are going up steep grades turn off the cruise and let it go back into third then ease up on the throttle untill it goes into lock up.

Then down shift to 3rd so it doesn't "hunt" shift back and forth from 3 to OD. Something I've found with my truck when towing is there are speeds/RPM's that the truck will like with your load better than others depending on your power, load and gearing. With my camper and set up I can tow at 75 MPH about 2250 RPM but the truck down shift a lot on smaller grades to maintain speed and it burn much more fuel. If I slow down to 65 about 1875 RPM it pulls steeper grades without down shift and MPGs are better. The engine produce max torque at about 18-1900 RPM and you will get best economy and best pull running close to that RPM, drive RPMs more than MPH.

[DaveBr]

If you let the truck kick back to 3rd by itself it won't go into lock up. You have to ease up on the pedal to make that happen. The reason your truck stays in longer at 65 is max torque on a stock engine is at 1800 rpm. The closer to max torque you are the better milage and grunt power you will have.