Is there a option for the axle ratio (3.73 or 4.10) when ordering a 2500HD D/A? If you build the truck on the GM website, you can pick a 3.73, which makes me think the 4.10 is standard. In the brochure, it says the 3.73 is "required". :confused: I want to get the 4.10 if I can.

Thanks for any info.

Steve aka "Trafficdude"

Nope, 3.73 is the only axle ratio avail-at least on the 2500. 4.10 axle is for the 6.0 gasser & maybe the 8.1

that suks! :( Thanks for the info.

Actually, unless you're upgrading to much larger tires, or are pulling large trailers at very low speeds, 4:10 gears are simply too deep for highway speeds. For example, my truck with 285 tires in 6th gear runs at about 2100 at 70..With 4:10 gears, bump that up to 23-2400 (which is on the down side of your torque range on the stock motor) This of course makes fuel milage suffer as well.
3:73 gears behind the stock duramax work very well to be honest..:)

Thanks, Partsguy662. I just wanted to make sure if the truck was rolling on 35" tires and pulling a 5er, I would have enough gear to do it.

Steve

Well, unless you plan on pulling that 5'er in the mountains 90% of the time and never plan on unhooking it from the truck, I would say the 3:73 gears will suit you just fine. Now, if it was just a tow horse and you're going to be pulling hills all the time, and you don't plan on going much over 70, then you might want the 4:10 gears. While GM hasn't offered that as an option on the Duramax equipped trucks yet, I keep hearing that it might be an option. Personally, I think they're making a mistake if they do start putting that gear set in these trucks simply because some people are going to use the truck as a daily driver and mileage will suffer...
(Please, spend my 2 cents wisely ):h )

I wonder why you can get the 4.10 or 3.73 gears on the 8.1 motor then??? It has the same allison tranny that the Duramax does. I like the 3.73 anyways, but I wonder if you can order one that way?

My guess is the 8.1 has a larger RPM band, so 4.10's don't wind it out as much. A lot of guys plow with those, too.

With the new 6-sp, 4.10's even with the stock tires isn't that bad of an idea.

I'm surprised GM is not offering it.

Truth be told, the intended speed for these trucks is 75mph max. With the 5-sp, that's only 2200 rpm.

Sorry to jump on this thread, but could anyone tell me if GT-4 is 3.73 Ratio?

I dont know about the allison equiped trucks but i honestly would consider 3.55 gear now i pull out in 3rd gear and 2nd on steep hills and with the trailer on 1st i think is just there to fill up an empty space!!!!

I agree with 05LLY. These trucks make enough torque to easily run a 3.55. Last summer I had 12k of wood pellets on the Gooseneck trailer. Even with the 265 tire I could start out in second gear without much fuss.:ro)

Sorry to jump on this thread, but could anyone tell me if GT-4 is 3.73 Ratio?

Darn thread hijackers...):h

Yes, GT4 is the code for 3.73 gears...GT5 is the code for 4.10 gears.. :)