3.0L Duramax 3.73 Gears

[barr8888]

On 2/1/2021 at 9:28 AM, John Sarappa said:

Some people don’t understand  there are people who would like to put larger tires on and bring the motor back into the same shift range etcetera as the 323. 373 should be available in every configuration and in GMC also!

 

This.

 

3.73 gearing looks to only be available in the Silverado with the 3.0L Duramax AND the 'Diesel Off-Road Package.'

 

Can anyone that has the 3.73 gearing (I believe that's RPO code GT4) verify if their front axle RPO is SU5 (a GM axle) or are they all SU4 (an AAM axle)?

 

I have a '22 Limited AT4 (SU5/GM front axle; SU7/AAM rear) that came with 3.23 gearing (on OEM 265/60/R20 tires).  Now with 35X12.5R20LT tires, correcting back to stock gearing works out to about a 3.48 (3.42 being the closest available).  But add in the extra unsprung rotating mass of the larger wheel/tire combo (around 18 lbs. at each corner), and slightly over-correcting to 3.73 gearing should be just about perfect for my needs.

 

Since aftermarket gearing is apparently as yet still unavailable for the front axle in the T1 platform trucks (I'm hearing that GM might actually be welding the ring gear to the carrier in these axles, too).  I'm trying to determine if GM OEM 3.73 front gearing will work in my SU5 front axle.  Any help would be greatly appreciated.

 

 

I don't believe the rear axle will be a problem, as aftermarket 3.73 gearing is apparently available there.  And while it's apart for gearing, anyway, I also intend to replace the factory 'gov-lock' locking differential with a more reliable Eaton Detroit TrueTrac.  I'm not so sure about ever coming down hard on a gov-lock with the added leverage 35" tall tires bring to the equation.