Rear End Gear Ratio

I have the same exact set-up - same - but I do drive 65 and my last three were: 7.8,7.9,7.7 - Run compliant - Make more/Keep more

 

A direct 10 would be ideal for all around use tied to a 2.64 or 2.79 rear. If it is a 10 over, then a 3.55 or 3.70 would be an all around good choice. That would be for a Series 60. You didn't state which Detroit (series 60 or DD15/13). The DD15 operates well a a little lower RPM than the Series 60, so for that I would consider a 2.47 or 2.64 with a direct 10, and 3.36 or 3.55 for 10 over. I have not been all that fond of the 3.42, though some like it.

I would concur with others that the 13 spd is the best all around choice and will cover 90% of what goes on in trucking. With something like that, running in 12th (1st OD) with something like 3.36 or even 3.25 rears would give a good performer with decent mpg running 57-60 mph. But finding that combination on a lot in a good truck might be pretty difficult.

 

i'd prefer 13 spd w/3.58s

 

I prefer 18 spd with 2.79's

 

I am looking at a 2006 9400i international with isx cummins, 10sp, 3.55 ratio, would anybody have any input about this kind of truck? It also a mid-sleeper. Thks alot. captredbeard

 

Depending on what work the truck would have to do and what speed one is intending to operate, that is a good all around setup. It is a standard, tried and true, setup that has been used by a lot of folks. it will handle, comfortably, most of what goes on in trucking. For a specialty application, not so much.

 

hello, i am looking for a used truck for me. I am pulling a flatbed. All the time around 80000. So i found one for me, but the only problem i have is it has direct 10 with 2:52 ratio with , what do you think about it? Let me know should i find another one or its alright? Thank you.

 

Roehl Transport is running Detroits with 2.47 gears in their flatbed trucks. Roehl's trucks have either 10 speeds or automatics.

 

and they suck lol.
but its the way roehl has them tuned. if they tuned then diff it wouldnt be a bad set up.

 

Direct 10 is a limited trans. Whether you go high or low with the rears it has its pitfalls. The 10 over, 13/18 are far better trannys. They have a much wider range of operation and create better mpg when pulling and hwy cruising.