My brother in law is visiting with his new 05 auto and we were wondering if it is just as important to lock out the od (tow/haul) in these new transmissions as it is in the 2nd gen ones like mine. That's of course when travelling under 80 kls or so.

 

whenever towing anything, use the tow/haul button.

 

Thanks carcrz, that is understood. Just wondering about the running empty times. I allways lock my od out when under 80kls/50mph which is a well understood practice to help preserve the life of the 2nd gen autos.

 

I don't see why you would need to shut it off then. If you are empty, the default setting should be acceptable. If not, Daimler Chrysler would have addressed the issue.

 

Essentially, what you are trying to manage is convertor slip. The 48re uses a lockup converter. In 3rd & 4th the converter is locked up at speed. When you let off the go pedal, it unlocks...that's where you build heat. What the tow/haul is doing for you, is raising the shift points, so that after the shift, the engine is not lugging. i.e. it cuts fuels consumption & heat in the engine by keeping the engine into it' power band. If you want to cut the heat, you may want to look into a converter lockup box.

On my '06, the trans temp will stay at 160-170 on the freeway. Soon as I come to a stop, it climbs to 180-200, depending on traffic. Once I get onto the freeway again, it will drop back to 160-170. Oh, and I also use the jake all the time, so the convertor stays locked up on deceleration...which is why I'm advocating a TC lockup box. You may also want to install gauges, so you can monitor what the trans (and other systems) is doing.

HTH

Tony

 

The TH raises theh OD shift point and line pressures for a firmer shift. It will hold drive until 45 or so and drop back into drive earlier.

I run mine in TH all the time. Helps with mpg, especially around town, to get the TC locked as soon as possible.