Hello all, Don here with a question...or two. I replaced a 460 gas engine with a cummins 5.9 diesel with 22K miles on a major. It is rated at 200hp.
My question is this: I have a 545 allison with no overdrive.
My tire diameter is 34".
I have 19.5 wheels.
I weigh over 20K.
Does anyone out there have a diesel with those size tires and no o/d ?
If so what rear end ratio is being used.
The wrecking yard sold me 3:21 gears and they are way too high. I am coming up with 3:73 gears. If there is a coach out there with these components will you let me know what rear end ratio you have. Thanks, Don

5.9B Cummins, 542 Allison, 8r19.5 tires, and 3.73 Rear End. This is a very common Barth Breakaway configuration.

Thanks Gary, it sounds like I might be in there with the 3:73 gears. What RPM do you guys run with this running gear.
Am thinking about getting a little more HP and RPM. I have the inline fuel pump and after cooled.
I believe mine is vacuum operated off the fuel pump. It seems to be frozen and no vacuum present. Any idea's??? Don
Hey, we go over to Yuma every winter. Have 5 friends over there....

Gary and I have the same diffy, but different trannies. I run at around 2100 RPM at 60 in straight drive (1:1), mentally correcting for the error in my tach.

Good info guys. I wonder if anyone has replaced a 545 with a later model OD unit. I know there is computer issues but is there a swap available?
What engine are you running 2100 @ 60 MPH?
I would like to get same results. I am getting over 10MPG but was climbing hills at 10MPH in 1st gear. Had trans heating issues also...Don

I have the AMG 6.5L TD 230HP, 4L80E tranny.

I replaced my 542 with an allison 2000. Do a search and you will find what I wrote back then.

With the 542 I ran about 2200 at 60 do to transmission slippage and almost 2600 to do 65. And yes it would overheat on a long montain grade.

I'm not sure what you are talking about with vacuum off the engine. There is no vacuum with a diesel unless some sort of generator is added.