Autos vs Manual transmissions

Yes, it's possible. Mostly light loads, mostly "downhill" (or mostly flatland running) with a tailwind like Denver to Houston riding a northwestern cold front passage. But in the real world, for most who haul refrigerated freight across the entire 48, this is simply not a realistic expectation. Just typical wind components alone will kill that expectation. Add in a 79k gross and a trip LA to Seattle or LA to Denver, forget it.

 

30 day average with DD13 and DT12 auto transmission 8.11 MPG. 60 day average 8.03 MPG.

Truck has Optimized Idle system. So computer start the engine for heat or a/c and battery charging and engine oil temperature. During a 34 reset the computers also will to automatic Parked Regeneration on DPF filter if need. Running the Midwest

 

No I meant with 200,000 ish b trains out west. After it's fine tuned.

 

Also took it on a ferry at that weight.

 

The current crop of Autos are burning through clutches and gears quicker then manuals ever did. Even in the hands of fresh meat at the megas, manuals are lasting longer.

GMC never wanted to put an automatic in a Buick.

GM didn't put an automatic in any production car in 1939.

In 1940 GM (not GMC) put an automatic in an Oldsmobile.

Once you get your facts straight, you may still want to know why? The only reason is --- in 1940s America few women drove or purchased cars. Automatics were only invented to get the little lady behind the wheel:

 

Where do you get information to base this comment on? At the Petro dining counter?

 

Good post.

 

Don't be hurt, we have a few sections here on trucks and mechanics. Hang around there sometime.

Other wise talk to a few of the mechanics. Not only the megas but look at some of the independents too and see how many automatics they have in looking for parts.

 

Where did you get 900 rpms? My engine doesn’t lug at all unless i start out in 6th gear empty and then briefly. I shift fast enough so there is usually only about a 300 rpm drop. My last truck had 650k on the original turbo, injectors, etc and didn’t use a drop of oil ever when they sold it. I run loads usually 25k or less. The truck before that I was in had about 900k and didn’t use any oil, all original parts, and I checked it every day.

You would be money ahead because of how much better I do fuel mileage wise if you kept the truck three or four years, but lugging a motor nowadays doesn’t shorten engine life, these motors make the most torque in low rpm ranges. What kills them is excessive idling, carbon packing, and not monitoring potential issues like coolant in oil, injector cups leaking, etc.

 

And liner fretting on the block is an issue with the Acert line of caterpillars due to the high pressure from the turbos and the head bolts at least with the acert my friend owned. I haven’t seen a truck in our shop with a liner protrusion issue on a Cummins, Volvo, Paccar or Detroit, and I have been here 6.5 years. Seen a few plugged oil filters starve a bottom end, but no catastrophic failures and no rebuilds at our company.