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Discussion Starter #1
I recently broke my stock locker and while I was in there replacing the locker, I was going to lower the gearing to compensate for my 35's. Which gears should I go with? Uses for the truck include: daily driving, occassional 1/4 mile track runs for fun and hauling a 28' travel trailer up to 1500 miles one-way a few times a year. I was told in another thread to go with 4.56's, but in a different thread I'm being told that 4.56 is too low...HELP...mechanically inclined responders only PLEASE.
 

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4.10's work great.
 

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4.10s are fine. Heck, you could get by with the 3.73s that are in it now if you want to. I'd try that first, and then re-gear only if necessary.
 

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The lowest I'd go is 4.10s.
 

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I had the same situation when I replaced the stock 32's on my K5 Blazer with 35's. Except I was going from a 3.42 ratio.

After doing all the calulations I selected 4.10's. This ratio most closely matched the stock configuration as far as engine RPM was concerned.

I believe Randy's Ring and Pinion website has one of these calculators, many other sites have them as well.

I agree with Budtx though, a change from 3.73 to 4.10 isn't that much different, especially with the power of our engines. You may want to try it first.
 

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If you don't ever want to drive over 60mph go with the 4.56. Just remember if you have a 4x4 that you MUST also change the ring and pinion in the front differential to the same ratio as the rear.
 

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I have a 6" RCD lift on my truck with 35" tires and left my gearing with the stock 3.73 and it does great even towing my 35' fifth wheel toy hauler. Save your money its not neccesary
 

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Discussion Starter #9
after speaking with a few folks on the subject, I think I've decided to go with a new locker and leave the 3.73's in there.
 

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If he changes gear to the 4.10s will he get better mileage? Because if he gets back the mileage he lost then it seems it would pay for it self in a short time. I was thinking of regearing just to get the mileage back. I lost about 2 mpg with the 35s.
 

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Taller gears will usually help mileage, so theoretically you will get better fuel economy with the stock 3.73s versus going to a lower gear. You probably noticed that your RPMs at 70 dropped when you went to the 35s with the stock gearing.

I'd wager that the heavier rolling weight and tread width (combined with your 6" lift) is what hurt your mileage.

Bud
 

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If you are going in there, change the gears, it's well worth it!

I am speaking from experience. I asked the same question before changing my gears and everyone had an opinion, but I guess very few have actually done it. If you have the 6 speed then go with 4.56, thats what I did with 35's and its perfect. If you have a 5 speed you would want the 4.10's. I picked up 3 mpg going to 4.56 with my set up, thats almost where I was before I did the lift and tire change, and the power, hang on! LOL!
 
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