What does overdrive do while pullin a trailer.What gears are good while pullin a 2H Sl Bp with Dr room in Al,Tenn,Ga,Ms and a 4H small LQ trailer with 1 or 2 horse
Posted 2006-10-16 8:43 PM (#50176 - in reply to #50175) Subject: RE: Overdrive etc..
Expert
Posts: 2689
Originally written by farmboy on 2006-10-16 7:59 PM
What does overdrive do while pullin a trailer.What gears are good while pullin a 2H Sl Bp with Dr room in Al,Tenn,Ga,Ms and a 4H small LQ trailer with 1 or 2 horse
O/D will typically engage later when pulling or hauling a load, though on some vehicles it will engage at the same speed. Basically, if your truck is laboring or the transmission is "hunting" for the right gear, use O/D lockout. GENERALLY, if you needed to lock it out on the way up a particular climb it is a good idea to lock it out on the way down.
Posted 2006-10-16 11:36 PM (#50185 - in reply to #50175) Subject: RE: Overdrive etc..
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Posts: 2453 Location: Northern Utah
Depends somewhat on the year of your truck. The newer trucks behave as Reg has stated above.
The older trucks. The Lock out stopped the tranny from shifting into the highest gear. So instead of going into 4th, the tranny used 1,2 and 3. so instead of cruising at 2000rpm you would instead cruise at 2300rpm. The higher rpm helped keep the engine from lugging. The extra airflow through the engine keeps the exhaust temps down and keeps the tranny from hunting gears as much.
Newer trucks with the electronic controlled tannys. (Ford Torqueshift and GM Allison) reprogram the tranny to use an alternate shift point programing when the Tow\Haul button is pushed. This allows the engine to stay in the Power Band vs Econmy band of the engines torque. It also programs the torque converter to stay locked up and help with engine breaking when tow/haul is engaged.
If you have a newer truck, Just push the button every time you hoiok up. They work great.
If you have an older truck, use the OD lock out if your tranny starts hunting gears a lot, or youwant to avoid lugging the engine on grades.
Overdrive etc..
