Model number for 18 speed single overdrive trasmission

But no one ever said that using an 18 and 2.64's would work in every situation. Obviously heavy haul in off road is not what a setup like that was intended for. But, OTOH, it is a realistic setup for the majority of trucks that do the refer, van, flat thing that never goes beyond 80K gross and spends almost all the time on the hard top.

 

There's no reason why you shouldn't be able to run that setup!! It would actually be a nice combination! Mant fleet trucks have that tall of a gear,with a ten speed! A 13,or 18 have a much lower low,and first gear! I've ran rears from 4:56 to 3:42! I haul some heavy stuff! I have a 55 ton trailking,and i've never noticed one bit of difference in fuel milage either! Had all size,and brand engine that they make!!!

 

I would not like to back that set up into a tight parking spot with a spread axle. I think even with a 18 reverse would be too fast most of the time.

 

I just went from 24.5 low pro tires to 24.5 and can tell a big differents in the way it pulls now with these 3.36 rears. And its not in a good way either! Why would anyone want 2.64's with any kind of overdrive tranny is crazy.

 

The idea is to run the trans in direct (16th) to cut down on driveline loss through the overdrive gears.
I dont know if its Bruce's idea but he spreads it around alot. Thats reason enough for me to be sceptical.

 

Actually only the 18 has the lower low at 14.40:1. A 13 is only 12.31:1 in low. A 10 over is 12.69 (1650 torque or lower) and 12.94 (1750torque and up). The 10 overs are actually lower than a 13. The fleet trucks with 2.64:1 rears run 10 directs that have a 14.80:1 low.

 

And .73 in the B.

 

I stand corrected then! Still no reason why you shouldn't do it though...I really think when people say that a truck with 4:11 gear will out pull the same truck with 3:36 gear are kinda crazy! It might be different if you were running a two speed powerglide,but when you have 13,or 18 gears to choose from, you can just about get at whatever speed you want at the rpm you wanna be at. Imo it gives you far more options!

 

Look up caterpillar gradeability chart on internet got some info there. U lose 6% gradeability for every rearend ratio u jump up. You could end up making truck hard to drive just my exp with 3,08 rears and 18spd running midwest to cali.

 

It probably isn't the perfect setup for everyone,but I'd like to have it!! The truck I drive is an 07 Exhd flattop Pete! We bought it "used" with 13000 miles from some friends!! The truck came with 3:36 rears,and they had them changed before they ever drove off with it to 3:70,and I think the truck would get better milage,and pull a little better at 70 mph then it does now!! It's an nxs 500-1850....it's in a desperate need of a tune! If I have it loaded to around 125000 both ways it gets down in the mid 3s on fuel,and it's pretty much a turd!!