My 02 had 3.55 gears in it and since 95% of my driving is highway, I loved it compared to my new 07's 3.73 gears.

How crazy would I be to swap a set of 3.55's into my 07?

Yukon Steel sells a 3.54 kit for my truck but I'd have more ease at mind knowing I have oem gears running in my truck.
http://www.xtremediesel.com/yukonrin...a354ratio.aspx

Any other ideas or alternatives for me?

 

Anyone actually running this aftermarket gear in their rig?

 

u can actually get 3.42s for your 11.5 axle in your truck, if u want a little taller. i loved the 3.54s in my 02 also, until i put taller tires on and starting towing. too much.

 

Know what your feelin, my 4:10s and NV5600 are a nightmare for mileage on the hwy
Not many reasonable options for a duelly in the taller tire department either.

 

any idea where I can get these 3.42's?

 

I wouldn't worry about running Yukon Gears. I don't have any of their products myself but I've read a lot of great reviews on other forums.

Aside from regearing the axles you can always go for an auxiliary transmission like a gear vendors overdrive.

 

my 99 and 01 had 54's both towed good, the 99 gross towing weight was 23.5K and never went out of OD on Michigan hills. if you needed more RPM, just push the OD button, i had to with my V-10

 

Stay away from gear vendor they do not hold up if you do a lot of heavy hauling, I have 3.73 and I do not have any trouble with it as for as fuel millage. I do pull a big fifth wheel. When I leave home my weight is at 23.000 and it stay that way about all the time gets less as fuel goes.

 

Ditto on that and they don't recommend using one with an EB.

 

3.42 from 3.73 is like a 500 rpm difference going 75 mph?

 

Are you that dead set against just putting on some taller tires? Seems like the easiest fix... but if you are, Yukon gears seem to hold up great...

 

Nope.

2171rpm with the stock 3.73, 1991rpm with the 3.42 for a difference of 180rpm. I think the biggest difference here is that it gets you below 2000rpm, which at least on my truck is the cutoff point for good mileage.

The difference between a 3.54 and the 3.73 is similarly small: 2060rpm from the 3.54 for a reduction of 111rpm

 

285/75/17 nittos or toyos (33.8" tall) would bring your rpms down and look good on the truck. With 95% highway, nitto dura grapplers would work great. I run the 285/70/17s (32.8" tall) with 3.73 gears.

 

Going to 285/70/17's the 3.73 will change the ratio to 3.58.

Going to 285/75/17's the 3.73 will change the ratio to 3.46.

MikeyB

 

The AAM axles in 03 and up trucks are not availble with 3.54s...only 3.42s as stated earlier. I figured with my 285/70/17s The 3.42 ratio will drop me to 2000 rpm from 2175 @ 75 mph. Will take a long time to pay for itself with a 4x4 truck. Less time with a 2wd.

Local shop qouted me $1100 dollars to install the ring and pinion at both ends if I buy the ring and pinions. They would supply the install kits.

There is also a ring gear spacer required to install 3.42s in the front axle ($140) from what I understand.

For the earlier trucks with Dana axles (02 and back) a 3.31 is available.