2022 T880 Endurant 12 sp 2.79 ratio

[Rawze]

(01-24-2024 )farmer_luke Wrote:  ...
Thanks. I wonder how long the engine will put up with being lugged at low rpms? Typical trips with grain are 80-90,000 lbs one way, either 20 miles or 80 miles, then back empty. I think the auto shifting can be set to different modes and you can run in manual to keep it in the gear you want.
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With those weights and short haul like that. you will have noting but problems and hate that truck in the end due to torturing it to death!.

And unless there is a specific reason for the auto-s$itter (handi-capped, etc.), I would highly advise against it, as they are very expensive to repair and maintain over the years vs. manual.. and are less fuel efficient across the borad vs. a decent driver.

- From your descriptions.. shorter hauls and over 80,000 lbs often.. you will be looking at something with a set of 3.90's on the tall end, but something with a set of 4.68's would be more appropriate though to get it up and going quickly so that it has a bit of ballz to it.

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As far as buying used trucks goes lately.. they are all upside down in gearing due to the morons buying them not knowing any better and the stealers$its pushing these tall rear ends that make the engine lug itself to death just after the warranty period, all in the name of 'saving fuel'
at the cost of cutting the the engine lifespan in half or less.

It is very difficult to find a properly spec'd truck these days. It is also getting hard to find trucks with stick too, because the mega-fleets cannot find drivers that have any intelligence .. and just about everything used with those horrible rear end specs also have close to half a million miles on them. This overly-tall rears makes the engine wear 2x, so they already have 1+million worth of wear (due to the torture below 1500RPM) on them. Engine is typically ready for a head gasket and other failures at any moment by then... costing the next guy who buys it big-time, putting them in a dark financial hole!.

Shop around .. and shop some more.. and then still consider replacing the rear ends as part of the cost needed for the operations you are describing.

You buy a truck with those garbage 2.79 rears, and EVEN IF SOMEONE PUTS 800+ Horsepower in it,.. it loaded above 80,000 lbs ... and it will still feel like it won't hardly get out of its own way!,.. no matter what YOU DO! ... because IT IS SPEC'D COMPLETELY WRONG FOR THE APPLICATION!. plain and simple!.

And to add insult to this.. you mentioned short haul .. which usually means several loads a day + a lot of stop and go in an urban setting, unlike a long-haul highway truck that moves at highway speeds for hours on end.

The more stop-n-go type of back and fourth operations there are,... the bigger the gear ratio needs to be to get the truck up and going, so that your not 3/4 a mile down the roads, and still trying to get it up to speed (hence my recommendation of 4.68's). This is exactly why dump-trucks are geared 4.68's and 5.11's.. for this very same reason.

here is a set of selection charts to help figure out the best gearing for an application...
ref: http://rawze.com/forums/showthread.php?t...7#pid63777