Re-gear and Detroit Locker in a 2017 2500HD 6 Liter

SierraHD17 · December 22, 2017

Not a question from me but since the information is so limited on this I will hopefully help someone else along the way. I am just beginning my parts scouring and gathering so I expect to actually redo the truck in January sometime. So far this is what I have learned. My 2017 2500HD uses the same 10.5" 14 bolt AAM ( based off the GM corporate 10.5") that GM has used forever. The GM parts department confirmed this for me by searching parts between an older truck and my own. This was my biggest question as nobody has any solid information posted whether it be parts or otherwise if the 2015+ trucks changed at all. The front is the same 9.25" IFS shared in all 2011 and newer HD trucks so that works very well too.

So lets focus on the front. I will need gears and bearings only as I am not touching the carrier. The gear set is common to any GM 9.25" IFS from 1988 and onward and only the bearing set is specific to 2011 and newer but that's it.

For the rear this means any GM corporate 14 bolt parts fit from 1973 and onward. There was a change with the pinion bearing in the mid 1980's but if you buy the appropriate bearing set for the pinion support you are using then it doesn't matter. So I went to the boneyard and yanked the open carrier out of a 1994 C2500 454 truck that had a 4.10 geared 10.5" in the back. This old heap of a donor truck was an open differential which for the purpose of my build I need. If you simply want to regear your truck and use the existing G80 Gov Lock you don't need to do this...... or if you buy a Trutrac, or a clutch pack limited slip of some kind. The Detroit however is a lunch box style design and drops in place of the spider gears inside a factory open carrier.

Something else unique to the 10.5" is the carrier split. What this means is the carrier is physically different depending on axle ratio and in the case of the 10.5" it splits at 4.56. Anything 4.10 and higher ( ratio, not numeric) uses one carrier and then 4.56 and deeper uses another. No problem but remember that my carrier came from a 4.10 geared truck. The aftermarket however makes "thick" gear sets that allow you use a lower gear ratio on the 4.10 and higher geared carriers.

Edited December 22, 2017 by SierraHD17

SierraHD17 · December 22, 2017

There is my beauty of an open carrier all nicely cleaned and freed of its old carrier bearings.

Got a bit of deal on the locker too. Went browsing on Amazon and low and behold there is the Detroit for a 10.5" advertised at $332 shipped! Now since I don't advertise, I am in Canada and that price is in Canadian dollars. Most places state side advertise the locker at $450 to $500 USD so this is easily half of that. Needless to say I clicked the Buy with one click option and got it sent on its way. Interesting to see what shows up when it gets here haha.

Edited December 22, 2017 by SierraHD17

crankman · December 22, 2017

Interesting thing to do to a 2500, have you considered on demand locker such as ARB so it will have good street manners. Then if you get in a bad spot flip the locker on and get thru.

Edited December 22, 2017 by crankman

SierraHD17 · December 22, 2017

No. I prefer the Detroit over anything. I have over 100000 miles with previous trucks such equipped.

sdeeter19555 · December 22, 2017

Having ran a Detroit locker in a daily, I personally wouldn't feel a selectable would be a benefit. They don't have that bad of road manners.

I would go the same route...

Steve
2012 2500hd

SierraHD17 · December 22, 2017

Yup. And I actually enjoy the manners on slippery roads over an open rear end or one that allows one tire fires. I got used to it and how predictable the truck was so now without I can't stand it.

sdeeter19555 · December 22, 2017

I'm watching your build, my next truck will go this route...

Steve
2012 2500hd

SMiller · December 22, 2017

What size tires are you going with? Would love to run a 35in. tire and 4.56 gears. Glad to see you are running a real locker, will make for a great setup.

SierraHD17 · December 22, 2017

Right now the truck has 295/60R20s and I easily will clear a 295/65/20 which is basically bang on a 35. I might go to the 35 once I need rubber again. My truck currently is 3.73 gears so this jump will be fairly significant and should be almost perfect.

mookdoc6 · December 22, 2017

Interesting? I would see this being louder and more counterintuitive than G80 and this is going to be driven on streets, hwy's 98% of time? To each is own I guess?

SierraHD17 · December 22, 2017

Not even remotely. Plenty of bad information out there from people that have no clue unfortunately. I can toss you the keys to my 04, not tell you it has a locker in the back and you wouldn't even notice. The G80 is a joke lol.

Grumpy Bear · December 22, 2017

I had a Detroit Locker in my second car on a 4.30 gear and loved it. Nothing to be afraid of.

sdeeter19555 · December 22, 2017

The only time you notice a locker is in a turn...If you power through, it will chirp/slide the inside tire. I drove one over 100k miles myself...once you learn how they operate, they aren't any more noticeable than an LSD.

Steve
2012 2500hd

Waaazooo · December 22, 2017

I thought these trucks come with a locking rear diff?

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sdeeter19555 · December 22, 2017

I thought these trucks come with a locking rear diff?

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Not in the same class...

Detroit is gear on gear...locked until you lift.

G80 is a hybrid, it is essentially a LSD that forces the clutches together so tightly that it won't slip. Lots of little pieces...

The Detroit is bulletproof...

Steve
2012 2500hd