GMC/Chevy Tow Haul Mode

[LI Pets]

You may want to get a weight on the AS, not what it is rated?

[Pahaska]

Originally Posted by jcanavera

I don't see that it provides any benefit on downhill grades though. If I'm in od it stays there.
Jack

Only the Allisonon has the downshift feature.

In response to Silvertwinkie, with the Allison, I see absolutely no need for an exhaust brake. I have descended steep switchback mountains and needed practically no brake.

In little ups and downs, as posted earlier, it sometimes stays in the lower gear too long. As mentioned, I simply hit the button to cancel tow/haul and, a few seconds later after it is in 5th again, hit the button to go back into tow/haul mode. This hasn't been a hassle.

[Silvertwinkie]

Hey guys, my bad, I was talking about my exp with a 4L80e. I drove a diesel based Allison once and it was a night and day difference in terms of transmission functions.

[CanoeStream]

We've got another thread going right now on cold weather diesel operation. BillTex posted a link about the engine coolant heater. I went there, poked around a bit and found this! Karma BillTex!! The engine mentioned isn't the LBZ or LBY of 2006s but I'll bet the system is quite similar.

Allison Grade Braking

[Over59]

Originally Posted by Pahaska

Only the Allisonon has the downshift feature.

In response to Silvertwinkie, with the Allison, I see absolutely no need for an exhaust brake. I have descended steep switchback mountains and needed practically no brake.

In little ups and downs, as posted earlier, it sometimes stays in the lower gear too long. As mentioned, I simply hit the button to cancel tow/haul and, a few seconds later after it is in 5th again, hit the button to go back into tow/haul mode. This hasn't been a hassle.

Ditto

Mostly I just drive without it engaged, it does save on brakes going down hills, at exits, and coming up to stops. Otherwise I just keep it in drive.

[Cracker]

With respect to "red-lining" the Duramax on long downhill grades, this question came up in the diesel forum and, as I recall, a direct quote from GM implied that no harm would be done. Apparently "red-lining" when not under load is considerably different than "red-lining" under load. I know that it happens all the time for me when I use the the Allison to hold my speed on long downhill grades. With the 2003 GMC, tapping the brake causes the downshift. I understand that this procedure has been modified on the later model GMC. How does that work? Does the tranny respond to the cruise control?

[SilverCabin]

Has anyone used a "chip reprogrammer" to get a tow/haul mode in vehicles not equipped with this feature?

Randy