I have ordered two sets (front and rear) of 4.11s from Randy's Ring and Pinion. I also posted a note with the online order that it was for an 08 AWD GMC Sierra Denali, and asked them to ensure that the gears would fit my truck. It appears that order has been shipped (althogh I haven't rec'd a tracking #).
However, I've now noticed on the order confirmation that the gears for the front appear to be reverse rotation and so I'm worried that they aren't the right gears for the GMT900 AWD, since I don't see anyone on here referring to a reverse roation gearset! The reason I'm worried is that they are charging me $326.00! for UPS shippping (from their Washington state location!) and I'll have to pay import tax on top of that as well, before I can confirm for myself if these gears can work! Can anyone on here say what the deal is with the AWD front gears? Are they Reverse Rotation or not? Any input would be appreciated.
These online gear vendors are really FOS. I've been looking for months to try to find any useful info on what gears to use in my truck, to no avail.

 

Also, the rear gear set has "ABS" on the Order as well? Don't know what that means unless it has like reluctor slots cut on the outside of the ring gear for the ABS sensor???

 

Here's a copy of the order confirmation:

GM 8.25-411 $396.24
8.25IFS GM 4.11 REV R&P (OEM) (2009&Older-See_Notes)
GM 8.5-411-ABS $337.08
8.5" GM 4.10 R&P(with ABS) 2-STEP - FACE TO FLANK SET-UP ONLY!! OEM

Can anyone confirm that these will fit my truck?
What the hell does "2-Step - face to Flank set-up only" mean?????

 

Got the gears. They are in fact 4.10s, made by AAM. I don't see anything special about the rear set, so I'm still not sure wth "face to flank set-up only" means? Randy confirmed in writing that they will work. I'm going to start on installing them today.

 

wish i could be more help to you bro, but cant...

good luck with your install

 

No worries, will soon find out. Got the front diff on the ground now! Will report back later on how it goes...

 

Got both gear sets in and they went in beautifully. Didn't need to change shims or reset backlash, bolted the gears in and checked backlash and painted the gears and checked the tooth contact pattern and they meshed perfectly. Drove it around last night. No noise/whine or anything from either diff. Well worth the extra cost of buying the AAM brand OEM gearsets.
The truck is now brutal on acceleration too. And much more driveable - no more hunting, lugging. Wish I had done this change long ago.
Going to take it to the track this evening to see what the difference in ET is.

 

good info, thanks for the update

 

Let us know how big the change is!

What did your pattern look like? When I installed mine, it ended up running off the toe a little bit. A .005" shim swap pushed the pattern way closer to the heel, so I moved it back to the toe. Yours similar to that?

 

im thinking of doing this as well.. how long did the swap take u? any pics? does it feel much faster.. only the 1/4 time will tell