CI DENALI

I am going to install 4.10 gears in my AWD Sierra Denali and wanted to know if anyone on here has done the swap as yet?
Here's the real stumper, according to GM, the '08 comes with 3.42 gears, but when I looked up the replacement gears for my VIN, it only shows a 3.73 and a 4.10 replacement gear set for the front axle. Does this mean that my truck has 3.73s in the front and 3.42's in the rear and the transfer box somehow makes up the difference in ratio? Is this the way that GM acheives the supposed 62% rear/ 38 % front torque spilt on the new AWDs?
If so how do change both the front and rear gears to 4.10?
Any guidance or input would be appreciated.

01WS6/tamu

iTrader: (36)

Front and rear gear sets are matched.
look in the glove box or on the drivers door to find the RPO code sticker.
gt4=3:42 gears
gt5=4:10 gears
g80= positrac

chevrolade

iTrader: (22)

i think u got 3.73s like mitch(sprayednali)hes awd as well,,,,,,mine is a 09'2wd,i got 3.42s.

man u are going to wrap up quick!! i wrap up quick enough with 3.42s lol,i can imagine the 4.10s,,,your going to need 4.10s front and rear,theres no way it would be different.

CI DENALI

Thats what I thought, I can't see how they could not have matched sets, unless they could make up the difference in the transfer case. I just don't get why then that there are no replacement 3.42 gears for front diff? My truck is supposed to have the 3.42s. I will check the sticker. Thanks.
I know that there was a guy on another forum that said he installed the 4.10s front and rear in his 08 AWD Sierra Denali and the truck was a beast. I know that with a 4.07:1 first gear that it would rpm real quick in first gear, but the other gears are spread out and 5th and 6th are so high that I barely use them. We have a maximum (yeah right!) speed limit down here of 50MPH and I run the truck in the 1/8 so the 4.10s would be better for me, IMHO.

01WS6/tamu

iTrader: (36)

oops sorry guys I messed up
GT-4= 3:73's

3:42's suck *** they are a gas mileage gear gm is going back the direction they went in the 70's and de gearing. You will love 4:10's and they are the only way to fly.

CI DENALI

Thanks, I know what you mean. My truck lugs in traffic unless I put it in tow mode and then the shift points are too high at part throttle.
I wish someone could tell me how I could get a set of factory front and rear 4.10's for front and rear for my truck for a decent price. I tried GM PartsHouse online but they say there is no 4.10's listed for the 1500, which I know is BS, because I can see them online. I'm afraid to order the part #s listed on ALLDATA DIY, unless I knew for sure they could fit. They suggested price for the ring and pinion set is like over $800 for the front and over $700 for the rear. And I'm not sure if it's a straight bolt in or whether they would need shimming, setting backlash etc.

03_Denali

iTrader: (1)

You have the same 8.6 and 8.25 differentials as everyone else. Go to Ron's Machine and pick up a front & rear gear set. I recommend that you pick up a tru-trac for the rear while you are buying! Yes, the gear changes are going to require setting up, ie backlash and shimming, by you or a shop...or you could just drive around in D...lol

CI DENALI

Thanks. I'll check them out. What brand of gear does Ron's Machine sell? I have installed several gear sets over the years in the GM salisbury type diff's and I've found that even when you get the checking difference and backlash right on, some brands (namely Richmond) still whine like a MF'er. Not to mention that they break too. I even bent a Richmond pinion- head once, in my old Camaro, launching it on Nitrous! It nearly drove me nuts driving it home from the track. The two sets of GM gears that I've swapped (one used set, from one vehicle to the next) were spot on and didn't whine, so I'm convinced that its worthwhile paying extra for the genuine GM gears, so that you can hear the radio without a banshee in the background. I've also heard that Motive makes the GM gears and you can get OEM quality from them without the GM price? Does anyone know anything about this?

wesasselin

I have an 07 sierra denali 6.2 2wd that came with 3:42s, i have tried both 4:10s an 3:73s in the 2wd the 3:73 are better the 4:10s and that low 1st gear made it useless imo but the awd may be different?? i used motive gears they whine we fiddled with them forever shimming and with amsoils best gear lube got them liveable but there is still some whine, american axle is the oem gear for gm and i wish i have spent the extra coin and went with them also the 2wd denali has a 9.5 rear end fyi

CI DENALI

Thanks for the input bro. I know what you mean about first gear. At 4.07:1, it's by far the lowest first gear yet for a GM transmission. The 4 spds were only 3.06, I believe. The only reason I am thinking of using the 4.10's is because my cam gives me like 1000 more useable RPM's than stock. It shifts at 6700 now as opposed to like 5600-5700 when it was stock. I have the 8.6 10 bolt rear, it looks like thats what the AWD comes with. I'm still on the fence about whether it's worth it and I honestly need to see if I can find tires that will hook the bitch up on the spray with the 3.42s, because the 4.10s would only make my traction problems worse.