3.08 gears on 4x4

Unr3al11 · February 23, 2015

I want the change my gears to 3.73. What's all needed to do it? Is it just ring and pinion? Also I know I need a different carrier but don't know if I need both rear and front or just front carrier?

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Chris · February 24, 2015

I want the change my gears to 3.73. What's all needed to do it? Is it just ring and pinion? Also I know I need a different carrier but don't know if I need both rear and front or just front carrier?

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Unless you are going from open to a locker, you shouldnt need a different carrier at all. Also not something you can do yourself

GRN69CHV · February 26, 2015

Lot of discussions on this. There are several different ways to go about this, no one best way so far. From what I can gather, no one is making a gear set other than the 3.08 that will use the stock carrier. What I assume is needed is a thick ring gear ring/pinion set or a ring gear spacer. AAM makes the rear axle assembly for GM, dimensional info is scarce.

Here are a couple links. First is East Coast Gear installing a Yukon gear set and carrier. Second is link to AAM aftermarket. From research I did, front carrier is a non-issue, stock carrier for 3.08 or 3.73.

http://eastcoastgearsupply.com/files/PDF%20Files/gm9-5-12-bolt.pdf

http://www.demandaam.com/

Personally, I'm going to wait it out and see if a true bolt in replacement gear set to fit the 3.08 carrier becomes available.

BlackZ71Silverado · April 19, 2015

Going to need a new carrier for a different gear set. The 3.08 carrier is different from all others. Good luck finding your parts!

$$$$$$$$$$$$$$$$$$

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white1500 · April 20, 2015

Stay with the current setup or get a new truck imo.

BlackZ71Silverado · May 8, 2015

To add to my previous post.......

What is your reason all of a sudden for wanting to change to lower gears?

Why did you buy the truck with 'fuel economy' gears to begin with?

Did you just decide you are going to start towing/hauling heavy loads?

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Cowpie · May 10, 2015

Stay with the current setup or get a new truck imo.

I did that. No matter what 1500 was available, it seemed that I was going to have to change a bunch of things, including gears, to make me happy, and there was no guarantee that I would still be happy with the results. I invented new swear words over my 2013 1500. Finally just took it in and traded up to a 2015 2500HD 6.0L 4.10 diff ratio. I am so much happier, and I don't tow very heavy, but I do haul quite a bit frequently. And mpg on this 2500 is as good or slightly better than the 5.3L 3.42 1500 I had before. Now that summer fuel is the norm again, 18 mpg highway is happening. Not bad for a 2500HD LT Z71 double cab 6.0L with snow plow prep package. I had a gut feeling I might not like the 3.42 in the 1500, and my gut feeling played out in reality. Can't even contemplate 3.08.

Stevens03 · May 10, 2015

Gears, master rebuild kit and a programmer is required to do the job. Your looking at around 2k-3k total paying a good mechanic to do the gear swap if you have 4x4. If its 2wd it will cost around $500-$800

gmyeah · July 30, 2015

I did that. No matter what 1500 was available, it seemed that I was going to have to change a bunch of things, including gears, to make me happy, and there was no guarantee that I would still be happy with the results. I invented new swear words over my 2013 1500. Finally just took it in and traded up to a 2015 2500HD 6.0L 4.10 diff ratio. I am so much happier, and I don't tow very heavy, but I do haul quite a bit frequently. And mpg on this 2500 is as good or slightly better than the 5.3L 3.42 1500 I had before. Now that summer fuel is the norm again, 18 mpg highway is happening. Not bad for a 2500HD LT Z71 double cab 6.0L with snow plow prep package. I had a gut feeling I might not like the 3.42 in the 1500, and my gut feeling played out in reality. Can't even contemplate 3.08.

I was reading some posts just for fun this morning and came across yours.....so, you really get 18mpg in with the 2500HD. I'm going back and forth on what I'm going to upgrade my 08 z71 1500 too. I've had to modify the heck out of it.......and I'll have to modify the heck out of next one too. If I do the math, I save about $1000 if I go with the 1/2 ton (with my mods). I figure that's ok with the idea I would also get better gas mileage.

My buddy has a 6.0L 3/4 ton silvy double cab.......12mpg without a trailer highway/town, 9-10 with a trailer. If I knew I would sniff 18 in a 3/4 I would be all over it. Is there a certain set a gears you have to get that mpg. I thought they all came with 4.10 in the 3/4 6.0L.

Thanks.

Cowpie · July 30, 2015

Yes. 17-18 on road trips. It has a 14.5 mpg lifetime average for all miles... in town, rural, gravel roads, off road on property, etc. Everything. That is almost identical to the 2013 1500 5.3 I had before. Now, to be fair, driving style has as much to do with mpg as anything. Fleet studies have shown that driver operation accounts for 33% of mpg differences. I don't drive like some old retiree, but then I have no desire to floor it from light to light acting like the traffic lights are my own NHRA christmas tree starting lights, or do 85 down the freeway chasing every sports car around. I would fall into what some might call, a moderate driver. Carries over from my semi truck driving. And the 5.3L in the 1500 had 3.42 diffs whereas the 6.0L in the 2500 has 4.10 diffs.

You will almost always do better on mpg with the 1/2 ton. You are moving around 1000 lb less right out of the gate! My 2015 2500 6.0L 4.10 double cab, Z71, with snow plow prep package, comes in at 7380 lb with two people, full of fuel, and about 200 lb of tools in the back. If the 1/2 ton will meet your needs, that could be the better way to go. Rear end ratios will be the achilles heel. They just don't offer any good work ratios (at least for my needs and operation) in the 1500 unless you really pull out the stops and get the 6.2L with every other high brow package that includes the 3.73. While, the 2500 with the 6.0, 4.10 is virtually standard across the spectrum. There is a 3.73 version in the brochures, but I have not seen one on a lot. The other problem with something like the 6.2L in the 1/2 ton, is that you are stuck on premium fuel, at least as recommended by GM. Depending on price spreads in your area, the 6.2L in the 1/2 ton and the 6.0L in the 3/4 ton are a total equal when it comes to fuel costs per mile. And that is assuming the 6.2L gets about 3-4 mpg better than the 6.0L, which seems to be the average difference. At least the 6.0L, you can put just about any fuel in it at the pump except diesel and it will run great. Mine has been on E15 almost exclusively since I bought it. E15 offers the best overall value for me on a cost per mile basis. And considering the mpg's I have been getting, it must be an alright choice.

crankman · July 30, 2015

Cowpie that's pretty outstanding mileage, my truck scaled at 7180 I see 13.8 on highway with no trailer and 10.8 with trailer attached. More power to you on your driving habits there very good. I guess my foot is a bit heavier. Might be that E15 i have never used it that might be the ticket.

gmyeah · August 2, 2015

Yes. 17-18 on road trips. It has a 14.5 mpg lifetime average for all miles... in town, rural, gravel roads, off road on property, etc. Everything. That is almost identical to the 2013 1500 5.3 I had before. Now, to be fair, driving style has as much to do with mpg as anything. Fleet studies have shown that driver operation accounts for 33% of mpg differences. I don't drive like some old retiree, but then I have no desire to floor it from light to light acting like the traffic lights are my own NHRA christmas tree starting lights, or do 85 down the freeway chasing every sports car around. I would fall into what some might call, a moderate driver. Carries over from my semi truck driving. And the 5.3L in the 1500 had 3.42 diffs whereas the 6.0L in the 2500 has 4.10 diffs.

You will almost always do better on mpg with the 1/2 ton. You are moving around 1000 lb less right out of the gate! My 2015 2500 6.0L 4.10 double cab, Z71, with snow plow prep package, comes in at 7380 lb with two people, full of fuel, and about 200 lb of tools in the back. If the 1/2 ton will meet your needs, that could be the better way to go. Rear end ratios will be the achilles heel. They just don't offer any good work ratios (at least for my needs and operation) in the 1500 unless you really pull out the stops and get the 6.2L with every other high brow package that includes the 3.73. While, the 2500 with the 6.0, 4.10 is virtually standard across the spectrum. There is a 3.73 version in the brochures, but I have not seen one on a lot. The other problem with something like the 6.2L in the 1/2 ton, is that you are stuck on premium fuel, at least as recommended by GM. Depending on price spreads in your area, the 6.2L in the 1/2 ton and the 6.0L in the 3/4 ton are a total equal when it comes to fuel costs per mile. And that is assuming the 6.2L gets about 3-4 mpg better than the 6.0L, which seems to be the average difference. At least the 6.0L, you can put just about any fuel in it at the pump except diesel and it will run great. Mine has been on E15 almost exclusively since I bought it. E15 offers the best overall value for me on a cost per mile basis. And considering the mpg's I have been getting, it must be an alright choice.

Thanks.....this is super helpful. I'll post what I get whatever I decide. Im just in the beginning stages now of deciding exactly what I want to do. In your note you mention the gears being the issue. I totally agree, but I'm pretty sure you can get the max tow package with 3.73 gears with the 5.3L according to the brochure. I'll double check, but for 2015 the max tow package has the 3.73 with the 5.3L and a 3.42 / 6.2L option.

Cowpie · August 2, 2015

That could be. I am not up to speed on every variation of all the pickups. From my experience, I made a huge mistake getting 3.42 in the 1500 I had.

Thing is, I have not seen a 3.42 that is worth a crap. But the OEM's across the spectrum are in a total love affair with it. Even in commercial semi trucks. It is such a lousy ratio in that mode if one is hauling anything heavy over more than flat ground. I cringed at first when I saw 3.42 in my 1500, but thought I might be ok in the smaller vehicle. Nope, I invented new swear words over it also. I wold not consider anything with less than 3.73, and I really am fond of the 4.10.

But like anything else, it is all dependent on the factors of what one uses the pickup for and where they operate it. The rural two lane, rolling hill, and gravel roads that are the primary area that my pickup operates, taller ratios like 3.42, and even worse, 3.08 are not very good choices. High speed freeway style driving on a regular basis, may be fine.