call the dodge dealer and or MB and ask.... let me know what you find cause I would really consider doing it!!!!

 

I agree with alot of the guys in saying the G56's are geared very deep. With stock tires and the older G56, I was turning 2250 at 70MPH. that was not the best fit for mileage, and really, 70MPH out west is pretty slow on the interstates. I have since put 285/75R17's on the truck, now it sits at 2050 at 70mph. This is pretty good for pulling and regular driving. I would think, either a deeper OD or 3.42's would really get the best out of the trucks. i can't see the Cummins needing to turn 2250 RPMS to pull many loads, plus, if you start to lose power, shift it down a gear. I like the tranny, it is the best shifting tranny I have driven, but the early gearing was a little whacky. I think a truck that turns right around 2000RPMS at 70 would be the best for overall power while towing and flat out interstate driving, not great at both, but good at them. Scotty

 

Are those 285's E-rated and if so has the taller tires affected your anti-lock braking? I am tring to find a E-rated 285 tire but know such luck.

 

Toyo has 285/70/17 and 285/75/17 with a E rating in the Open Country AT series. No changes with the ABS.

MikeyB

 

I've also seen an E-rating against BFGs 285/65/R20s, but that means u'd have to step up to 20s, not a cheap solution, but it does get you a 34.6" tire on there to help out the G56.

 

Im pretty sure the 6th gear is a planetary gearset on the rear output, and I would imagine that the number of parts to upgrade to the new OD ratio would only be a couple of pieces, however I have never worked on a tranny that uses ATF and i would inagine the tolerences are much tighter...does anyone have a exploded diagram of the g56???

 

Mine was made in august and it has the lower geared g56. I hated it with the factory 265's, but after I put my 35's on it I think its dang near perfect. I run 70 at about 2050 now. Made it alot quieter in the cab too, the drone of that 5" at 2250rpm runnin 70mph would drive you nuts.

 

I was unaware that the G56 had a planetary gear set...learn something new every day!

 

so redeyed is my idea not as offbased as some others may have insinuated?
or is just changing out the overdrive going to mess with everything else?

I would imagine that the newer final overdrive ratios is what is being used in the new trucks with the 3.42s and not the older lower geared tranny so it must be ok to do both. remember

" I just wanna go fast"

 

Can you imagine an 08 with the new higher G56 and 3.42's w/ 315"s? holy smokes, you would be going down the highway doing 70 in 5th!

 

that would rock

 

I just looked it up... if you can buy just the new 6th gear I am pretty sure that is all you would need..actually you might need a new 5-6 synchronizer hub too.

 

BTW 6th gear comes off first so that is the only part of the trans you need to take apart...granted you still have to split the trans in two to get to 6th gear...lol

 

Cool spreadsheet!

 

My tires are E rated and have a load range of 3970lbs at 80psi. And the 285/70's have a load range of 3750lbs at 80psi. I think BFG has a 305/65R17 with a load range E also. Either way, the Toyos are great tires so far, they roll smooth and give a little more load rating ove the stock tires. No effects on braking either, matter of fact, I really can't notice any difference other than better fule mileage, less RPM's at 70 and better looking. I think the 285/75 is "almost as tall as a 35 inch tire, just narrower. Just from parking beside my buddys truck with 35-12.50R18's. Overall they have been exactly what I wanted, and as long as they go at least 40K I will be happy with them. Scotty