changing rear ends

http://www.eaton.com/ecm/groups/public/@pub/@eaton/@roadranger/documents/content/ct_062746.swf

 

What kind of truck, motor, etc.

 

Do you have a 13 speed with single OD or Double OD?

The double OD with a 2.79 running lower rpms for better fuel mileage.

I have 3.36s with my double OD 13 speed with 22.5 lp SSs @ 1200 rpm running 57 mph in 13th, but due to other mods and light loads I am 9+ mpg with my 3406E Cat in a Volvo 770. My truck is a 6x4 and I may convert to 6x2 with a tag using the 2.79 gear running in direct drive 11th gear.

 

The axle ratio is approximately a 4% difference so your fuel mileage will improve that much, depending on the engine and cam even more.

 

Jesus 9 MPG???? What kind of mods and whats your average load weight?

 

I popped a 9.5 avg today with a Detroit 60, 18 speed, with 2.64 rears, running in 16th direct. Half the day was with 45K in the box and the other half of the day with 15K in the box. One leg of it, I got 10.3 mpg. Sure was great to have a calm day for a change! That was running at around 1400 rpm / 61 mph most of the day. Most of the time was in Michigan, so was relatively flat.

 

Some things just need to be seen ! This is a 1200 gal avg. Weeks I am in the mountains it slips , but almost always heavy.

 

I would like to thank Jesus my Lord and Savior for the many Blessings he has showered on this very Blessed Man!

Thank you for bringing it up.

 

How is your truck spec'd and what do you pull?