2.62 gear ratio

Wow I just don't know what to say. That really takes the cake. You completely glossed over post #117 didn't you? You're somehow assuming the transmission has no role to play, when in fact it has a larger role to play than the rear gears.

 

Now to get back to reality, the loss of O/D compared to D/D, is under 10%, probably lower than 5% in the real world. No one that is looking to run a D/D trans is guaranteeing a 1 MPG fuel savings. So now look at a maximum of 10% better MPG's, then figure the ROE?

 

let's just agree to disagree. I was just trying to say from the beginning that 3.70's would out pull 2.62 and fuel mileage and hill climbers don't come in the same truck.

 

Cool. I'll agree to disagree. Mine pulls quite well with 2.64 with an 18 spd and gets comfortable mpg as well.

 

They can if you spec it right.

 

It was not me that stated a 1 mpg improvement. It was mentioned in an earlier post. The $14,000, I believe, was for much more than a transmission and rear gear change. I believe the customer also dropped the power divider, and rear axle, installed an air lift, and shortened the drive shaft.

A 1 mpg increase ostensibly seems plausible, but I have no proof or experience in the conversion. It would undoubtably free up 25-30 hp, and drop maybe 500 lbs. Is subtracting that much hp from driveline loss worth anything, don't know.....

I think that most fuel mileage gains comes from aerodynamics and speed, but I am obviously not an engineer...

 

Shhh don't be talking like that, everyone knows that trucks get the best fuel mileage at 70 mph because of the "sweet spot" or something...

 

if you say you can pull a hill as good as same spec truck with 3.70 I believe you.

 

after the knowledge I've gathered from this I have to call eaton and ask why they make different ratios, just seems like a waste to make more than one. if one ratio can get the best mileage and pull the best and run the fastest they should just stop making all the rest.

 

I'm think'n 18 sp with 1.1 gears would let you run on the low side all the time?

Just another old fart that started driving late 70's , just switched out 355's for 370's W/18918B and LP 24.5 could never run in 18, probably should've went with 390's.

Nuther old fart question, if direct is so much more fuel efficient, how come the tran temp runs 20-30 hotter in direct than OD?