axle ratio options designations

[CaseyR]

Think I might look at a couple of used Duramax 2500 HDs this weekend. Can anyone give the codes that indicate the axle ratios? I have yet to look at one but I am assuming all the option codes are listed on the glove box lid like on my '94.

[heartbeatcanada]

Dmax only comes with 3.73's, no other option :(

[CaseyR]

Thanks, I thought that might be the case. However, I read posts with people talking about getting lower numerical ratios so was just wondering.

[DA BIG ONE]

Aftermarket would be option.

Keep in mind the ring is larger in those diffs.

[skark_burmer]

I just bought a 2005 Dmax 4wd and it has 4.10 gears, i think almost all come standard with these now cause that is what was listed on the window sticker as standard equip.

[DmaxMaverick]

The 4.10 may be listed as standard equip. on a 2500HD. This changes as soon as you option in the Duramax engine. The only ratio, either manual or auto, is 3.73. If you get one with a 6.0L or 8.1L, 4.10 or 3.73 is an option.

Your truck, unless someone made a huge mistake, does not have 4.10. It is 3.73. The option package details should show this.

[YZF1R]

Can you still only get the 3.73 with the six speed Allison? I would have wondered if they would lower the rear now that the Allison has a double over. If people were voicing concerns about busy shifting with a single over, I was wondering how the truck would be with a double over and the same rear. I have no first hand experience with the new one. Maybe they just won't allow it in sixth until 62 mph or so.

Steve

On edit: This post is assuming you have a Duramax.

[Chris611]

Can you get 3.43 gears in the DMax? I had a farmer tell me the other day that his buddy got a DMax with 3.43's and was getting 23-23 MPG highway and didn't feel there was much power loss for trailering compared to the 3.73's. Is it possible to get the 3.43's.

Chris

[jbplock]

Chris,
Unless it's changed with the 06 models, all Duramax/Allison 2500/3500HD's get 3.72 gears. However, the new 6-speed Allison is reported to yield an effective 3.42 gear ratio when running in 6th gear - 1800rpm at 70mph compared to 2100rpm with the 5-speed.

See 3.42 gears in a '05 2500 hd Dmax? (http://forum.thedieselpage.com/ubb/ultimatebb.php?ubb=get_topic;f=7;t=006321)

smile.gif

[mark45678]

on the glove box door gas or diesel trucks Chevy or GMC.
this has been the same codes since the begining of time!


GU4 = 3:42
GT4 = 3:73
GT5 = 4:10
G80 limited slip