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Hello, just picked up a 2001 Sierra 2500HD with 8.1 and Allison. 4.10s and 11.5” rear end. Previous owners did a solid axle swap with a 78 Ford Dana 60. A lot of little things to fix here and there. They didn’t address the ABS sensors so the dash is lit up like Xmas.
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Discussion Starter #3
That is awesome. What a bad ass setup. Welcome, I'm definitely interested to hear your plans for the truck!
Well it has 101k miles. The owners put 37s on it. Trying to research and debate if I should regear or not. I am from the Overland community.....I have a 2010 Hummer H3 Alpha (5.3 V8) with off-road package (front and rear lockers) so i do have a trail rig already.....this is a side toy so I have options
 

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4.56 or 4.88 gears would probably make it more enjoyable to drive with more pick-up around town. Those trucks could have come with 4.10s from the factory with 31ish inch tires so 4.88s would probably be around right for 37s
 

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Discussion Starter #5
4.56 or 4.88 gears would probably make it more enjoyable to drive with more pick-up around town. Those trucks could have come with 4.10s from the factory with 31ish inch tires so 4.88s would probably be around right for 37s
Good to know......I might go to 40” tires on this if it can clear them, previous owner had 38s at one point. Doesn’t look like the axle was moved forward much of at all when they did the swap. But the lift height is 9-10” though

also forgot to mention I have a 2005 1500 also as my daily
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The torque the 8.1 puts out prolly won't even notice!! Could buy some zero rates to push the axle forward. If you want close to stock, divide the tire you want by the stock size, multiply by current gear ratio. Ex; 40/31=1.29, times 4.10=5.29. Check out 4lo.com, they have a bunch if calculators. Also, you can put ABS on an SAS. Need to turn down the back side of the hub, use the tone ring off the CV shaft. Then just need to make a bracket to mount the ABS sensor. I was at a truck show and Quigley had a booth there. Saw the hub. Simple, but it works.
 

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Mmm Sandwich
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The torque the 8.1 puts out prolly won't even notice!! Could buy some zero rates to push the axle forward. If you want close to stock, divide the tire you want by the stock size, multiply by current gear ratio. Ex; 40/31=1.29, times 4.10=5.29. Check out 4lo.com, they have a bunch if calculators. Also, you can put ABS on an SAS. Need to turn down the back side of the hub, use the tone ring off the CV shaft. Then just need to make a bracket to mount the ABS sensor. I was at a truck show and Quigley had a booth there. Saw the hub. Simple, but it works.
You notice.

Gears are the best thing you can do for a lifted truck.
 

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TEAM FUEL MOTORSPORTS
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Welcome..... Nice setup! I have an 8.1 as well. It’s been a great truck.

I’d definitely regear for the bigger tires. The 8.1 handles the larger rotating mass pretty well. But, a regear will bring you back to OEM ratios and take a lot of stress off the engine/trans.

I suggest 4.88s. Mainly bc I have a set of 11.5” AAM Motive brand 4.88s that I’ll make you a great deal on as I don’t have a need for them. 👍🏻
 

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Discussion Starter #10
Welcome..... Nice setup! I have an 8.1 as well. It’s been a great truck.

I’d definitely regear for the bigger tires. The 8.1 handles the larger rotating mass pretty well. But, a regear will bring you back to OEM ratios and take a lot of stress off the engine/trans.

I suggest 4.88s. Mainly bc I have a set of 11.5” AAM Motive brand 4.88s that I’ll make you a great deal on as I don’t have a need for them. 👍🏻
At the risk of sounded dumb or out of the loop, never heard of Motive Brand. Sounds like regear is highly recommended. I’ve decided I will just stay with 37s. Rig is tall enough as it is. But I do want to convert the rear to a shackle flip and remove the tall blocks. Maybe I can even remove the traction bar thingies.
 

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Mmm Sandwich
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You would be good with either 4.56 or 4.88 if you like to party. Gears usually scare people off and than they make excuses on why their truck has plenty of power when it doesn't.
 

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TEAM FUEL MOTORSPORTS
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Yeah, Motive is a well known brand..... along with USA Standard, Yukon, AAM, etc.

I ran 37s on my HD for years at 10-11”. Then I went to 38s. I’d planned on putting the 4.88s in my truck. But, never got around to buying the front gear set and eventually lowered the truck down.
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