I just bought a new Duramax with six speed auto tranny. My questions is what is the propper usage in maual mode and when does it need to be implemented.

My sales guy said it can be used to slow the truck with heavy loads, but he didn't strike me as the brightest of individuals.

This link will give you some more info:

http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=SA4115EN.pdf

Basically, it has two purposes: It can lock out the overdrives (or any of the other gears above 1st) if you want or need to. Second, it can take the place of grade braking for those who would rather control the downshifting instead of the TCM while going down a hill.

It's pretty much only useful in inclement weather.

Works well in mountainous terrain if your trying to keep rpms up and speed down (both uphill and down).

DEWFPO

just put it in drive and enjoy the truck, the only time you mite use is if your stuck. Do not use in hills to hold back that is what the tow/haul mode is for.

I've found it very useful in the mountains towing a large 5th wheel at low speed. Better control and lower temperatures when I select when to use 1st or 2nd and take it out of drive. In that situation I've also found it good for slow speed grade braking. At speed I just use the grade braking feature in tow/haul, I find it works great by itself.

When breaking in my motor I used it to engine brake on rolling hills near my home after a 500 mile of easy but sometimes up to 70mph driving. This wasn't hard driving but letting the motor brake without any sort of over reving. In drive it would just coast down hills. The motor braking oils the cylinders and cools the motor. There was a link somewhere on this site that advised braking in a diesel this way. Since broken in I have used it when loaded when in cities going between stop signs block to block. Helps save brakes.

You just need to play with it and see what it can or can't do for you. You wont hurt it by experimenting with it.

that could be taken so many different ways mike ):h

that could be taken so many different ways mike ):h

You have a filthy mind mister.):h

You have a filthy mind mister.):h

that is true... my mom always said i'd go blind...... things are getting a little blury from time to time!!!!:eek:

that is true... my mom always said i'd go blind...... things are getting a little blury from time to time!!!!:eek:

I thought hair was supposed to grow on your palms or something.:eek: :cool:

There was a link somewhere on this site that advised braking in a diesel this way.... Helps save brakes.

Very beneficial for seating rings in any engine, loads them without the compression forces from above the rings. I have a mountain route and can maintain 3000+ rpm for up to a half mile off the pedal. Now at almost 3000 miles after a dozen trips I've broken 20 mpg. I'll lay off soon since it does wear rings faster, almost time to start using the brakes. With this tranny downshifting like it does by itself, the brakes should last much longer than average...

While pulling our 5vr, I found that controlling the transmission manually while going down long grades, worked better for me. Grade Braking works great, but I found that the engine revs were too high (4000+RPMs) to give me a warm and fuzzy feeling. Instead I controlled the engine speed to a maximum of 3500 RPM using mainly 3rd and 4th gear. This gave me a safe downhill speed.