Just came back from Glamis yesterday and when I was out there at the bar we parked next to an 05 dmax. He had 325 X 18 Nitto's on it so I asked if his milage was affected by the bigger tires. He said with the 4.10's it was still around 15mpg and he only had 13,000 miles so far. I asked who he got the gear set from and he said the truck came with the 4.10's. I asked if he was sure and he said he was absolutely sure and went on to say he also got a front locker. When I asked him how he got this and he said that his friend is a fleet manager for a Chevy dealer in California and when CalTrans was putting in an order for their fleet his friend just added his truck in. Is it possible that CalTrans can put in an order for a dmax with 4.10's and a locker and the general public can't? Would have been nice to have a gear and locker option.

LA DMAX

I know that you can get 4.10 gears as an option, my dad has them in his 05' 1500 c/c Z71. I have not heard of the locking front diff option though. Maybe he was mistaken because you do get a rear locker in the new trucks.

4.10's are usually options for gassers. I've not seen the option of 4.10's for Duramax..

I was told 4.10 was NOT an option for Duramax.

Man I think he was BS you, you cant order them with 4.10s and as far as a locker in the front from the factory I highly dought it. Also with 4.10 gears I cant see how he would drive it any faster then about 45 mph on the highway since the dmax redlines at I think 3200 rpm.

If he has a front locker, where is the switch? There are two aftermarker options that I am aware of--the eLocker, Eaton electric locker and the ARB air locker... Both should have a switch and wiring or tubing going to the front differential.

I have no doubt that you can get dealer installed 4.10s, but I doubt the locker. The 8.1L gasser can be had with 4.10s.

The dealer here, said the same as cid & 05hd.

FWIW, 325/18/65s will not make the Duramax scream. Those would be 34.63 inch tires, which would still be a slightly undergeared with 4.10s. A 33 to a 33.5 inch tire will work better with 4.10s.

Nope if it were true he could surely drive just as fast as a guy with 265s and 3.73s.:rolleyes:

My '05 GMC came with 4.10 gearing. I got it in October. You can still configure them that way on the GMC website.

Since when can you get a 4.10 with the dmax? You cannot configure it that way either on GMC or Chevy's website.?

My '05 GMC came with 4.10 gearing. I got it in October. You can still configure them that way on the GMC website.

gas or diesel?

How do you know what you have for sure? I asked when I bought my 04 a couple weeks ago and the service manager said the Dmax's only come with 4.10's. I didn't think that was correct, but I'm no expert.

The only for sure way is to count teeth or wheel rotation versus driveshaft rotation.

BUT, checking your codes in the glove box door is 99% accurate. GT4 is a 3.73. GT5 is a 4.10.:cool:

The Duramax/Allison HD package comes with the 3.73s.

Dmax/allison combo's are not available with 4.10 gears or posi fronts from GM in 2500hd 0r 3500hd. I checked with my fleet rep today and he confirmed this. Yes the 4.10 is available in the 8100 and standard with the 6.0. No posi front in any.

I wish I had known what T-rex was saying about the glove box thing and I didn't ask to inspect his truck, just thought it wasn't right since he and his wife and kid were leaving as we were getting there. I was just wondering if since it came through a CalTrans order they may have different accessabilities to options. Kinda like the CHP interceptors had more heavy duty coolers etc... that I don't think you could get unless it was a CHP car. Oh well, if I ever see him again I get into details.

LA DMAX

Although I think the guy was pull'n your chain, especially with the locker front end, it is possible for a bulk buyer to get GM to retool an assembly line for a specific option. I've seen PG&E get GM to do it.

BTW. Caltrans builds their trucks for longevity and mileage. That's why they get diesels. Getting 4.10's would be going against that.

Just my .02

Rich.

Dmax/allison combo's are not available with 4.10 gears or posi fronts from GM in 2500hd 0r 3500hd. I checked with my fleet rep today and he confirmed this. Yes the 4.10 is available in the 8100 and standard with the 6.0. No posi front in any.

:exactly: :exactly: :exactly:

If GM would have had that option, I would have saved alot of money. I changed my gears to 4.11 with 35's.

HD Trucks

6.0 = 4.10
8.1 = 3.73 or 4.10
Dmax = 3.73

No other options and the only factory locker is in the rear. I don't know where people get this stuff:drinking:

Just one of those guys who's got a nice truck and doesn't know what's in it... or thinks he can bs people. Good thing for this forum to prove it wrong... I'm sure he could have had those things, but unlikely a dealer would put them in. I *know* the factory won't!

As I understand it, the Duramax comes ONLY with the AAM 1150 rear end.
(Easy to spot by the torsion damper on the pinion.) The AAM supplied to GM comes ONLY in 3.73; the one supplied to Dodge comes ONLY in 3.42; there exist gears to run 4.10, or 4.11. The gas trucks do not always come with the AAM 1150, so they can have different gears. Perhaps things have changed since I looked into it last year.

Just came back from Glamis yesterday and when I was out there at the bar we parked next to an 05 dmax. He had 325 X 18 Nitto's on it so I asked if his milage was affected by the bigger tires. He said with the 4.10's it was still around 15mpg and he only had 13,000 miles so far. I asked who he got the gear set from and he said the truck came with the 4.10's. I asked if he was sure and he said he was absolutely sure and went on to say he also got a front locker. When I asked him how he got this and he said that his friend is a fleet manager for a Chevy dealer in California and when CalTrans was putting in an order for their fleet his friend just added his truck in. Is it possible that CalTrans can put in an order for a dmax with 4.10's and a locker and the general public can't? Would have been nice to have a gear and locker option.

LA DMAX

He probably had the dealer get the gears and locker installed before he took delivery. I have see new trucks dropped off at a 4x4 shop in my home town by dealers, to have that stuff done before delivery.

We build some truck equipment for Caltrans. They are very very picky. I would suspect the trucks were sent to an upfitter.He probably had the dealer get the gears and locker installed before he took delivery. I have see new trucks dropped off at a 4x4 shop in my home town by dealers, to have that stuff done before delivery.http://www.dieselplace.com/forum/images/smilies/exactly.gif