Anyone thought of the feasibility of swapping in a set of Dana axles from an '02? It'd probably be cheaper to buy a set from a junkyard than it would be to buy and install new gears. I'm pretty certain the back would be an easy, direct swap, but the front may present a few more challenges...

 

The rpm's on my '07 w/g-56 were brutal even w/285-70-17's. I upped to 285-75-17 Toyo MT's. RPM's are down but mileage was killed do to the mudtread. I may try the Nitto Duras next,but that's going to be awhile as the MT's have 14/32 after 10K.

 

For you guys with the early G56, you could swap a G56 from a 6.7 (07.5) and up truck to get a .74 overdrive ratio. The 5.9 G56 is only .79 overdrive.

Final drive with 3.73 and .79 is only 2.94, with 3.73 and .74 is 2.76.

I just sold my 08 g56 tranny.

 

Just thought I would add.....My 03 with 3.73 and a 5600 (.73) equates to 2.72 final. With a 3.42 gear set, 2.50 would be my final drive ratio.

 

I put the 3,42 gears in my truck with the g56 and with 285's on it turns at 1800 rpm at 65 mph . I am now running Yokohama 315's and at 70 it now runs at 1750 rpm . I like the change and the fuel mileage change it went up about 2 mpg . I pull off and on and have no trouble with it. Got the gears from west coast diff with the mini install kit for under 1000.00 and installed for 600.00 . Well worth the money to me .

 

http://www.justdifferentials.com/ind...acturers_id=43

They have the 3.42 gears and setup kits. I do not know for sure about a spacer being required on the 3.42 front, but it wouldn't surprise me. They also sell a truetrac for the rear end. I am loving mine so far. You can get the electric locker from the front of a power wagon there also. I haven't dealt with them yet, but they are one of the only places I have found selling OEM AAM parts.

 

Not all 5.9 G56's have a .79 OD. Some of the late 2007 5.9's have the .74 OD ratio. Mine was built in Dec 2006 and has the AE G56 with the .74 OD.

 

Randy's Ring and Pinion has the 3.42's plus the install kit for less then 900. I'm having them put in at the end of the month. Then onto 285/75's. At 65mph, I'm at about 2100. I'm mostly Hwy and back and firth to Huntsville takes forever at that speed.

 

I used a Yukon Ring and Pinon set-up on my frt Dana 60 axle on my 86 Chevy. I changed to 3.73 from 4.10, and they've held up well......nice pattern when I did the initial set-up. Think I got the kit from Randy's Ring & Pinon. Just clean out the interior of the axle housing real well, so you can start out w/ everything clean. Have a professional do your ring/pinon setup if you haven't done this before. You only want to do this once.

 

my concern with a 48re and 3.42's is the rpm's will be so low the fuel economy will actually worsen

 

I run 295's with my 4.11, and it has a pretty good cruise of 1900 at 72... you may want to look at taller tires. It is the least amount of question marks.