Oh, and your glovebox sticker lacks the RPO NHT code as well, further proof that the vehicle does not have the Max Trailering Package. Mine has NHT just to the right and down from the G80 code, which is to the right of the GT4 code.

 

You are correct! I did some googling and found this site.
I have the K5L package which tows 1k less than the NHT. Glad i figured this out before i made an even bigger *** of my self.lol

So your suggesting getting a 373? I like the 342 its a decent gear and gets good mileage.

However i have a company gas card and would love to get some more punch out of my rear gear.

http://eogld.ecomm.gm.com/NASApp/dom...&page=&butID=8

 

i have also noticed everyone calling these motors a L92 but it's a L9H a flex fuel model. Is that the only difference?

 

Yup, only difference all the goodness of the L92, plus the mods necessary to run the E85.

 

You are right about the K5L; the RPO code is on your sticker. K5L is the heavy-duty cooling package.

As far as the gear goes, well, I guess that depends on what you really want. Do you know anybody with an NHT truck you can drive to find out if it will be enough for you? I also would advise that you spend some time on an online gear/speed calculator so you'll have an idea what RPM you'll be turning at certain speeds and to see where your transmission will be shifting after the gearing gets changed. A couple minutes of searching should turn one up pretty quickly, and it's better to spend a few minutes looking than a few months (or years) regretting a decision.

 

I don't know anyone with a truck even close to mine. What rpms do you run between 70-80mph?

 

Just ran his tire height in a calculator. Im coming up with 1793 RPM @ 70mph with 32.73in tires w/3.73 gears and 2054 RPM @ 80mph

Also im going to side with just about everybody else on this, if you get to far away from the 3.42s your just going to have a bunch of wheelspin from a deadstop, I know a few people with full bolt on 6.2L and there already complaining about first gear being useless with 3.42's lol. Now thats from a performance standpoint

From a towing standpoint I could see (Especially if you tow alot) it being benifical for highway mileage, with 4.10's you could definetly keep that sucker in six gear when towing and avoid all the downshifting for the most part. Just food for thought

 

Easy - just do the math . . .

With my stock 32" tires and 3.42s, mine turns almost exactly 2000 RPM @ 80 MPH.

Since the 3.73 gearset is almost exactly 9% lower than the 3.42, then you'd be turning 2180 RPM @ 80 MPH. With a 4.10 gearset, you'd be turning almost exactly 20% more RPMs - so 2400 RPM @ 80 MPH.

 

i pull under 2k rpm on freeway and it drones bad and doesnt have a problem getting up and going. I am just looking for a steeper gear. I never tow anything hardly. Every once in awhile i tow a 12' tandem trailer but thats it. I'm just not satisfied with how the 3.42 drives.

 

Does anyone know the size of my 14bolt?
I was looking into getting some 373 gear but i am unsure of the size.

The3.42's seem to bog down when i am cruzing 60-70 mph as i am running under 2k. I am sure the new gear would help lose some of that hesitation.