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I just recently made my first purchase and love it. I have been driving my fathers 99 off and own since he bought it new. He averages 19ish mpg in town. Mine is hovering around 17ish. Not too bad since I only have 25k. I keep hearing that fuel mileage improves with more miles on the engine. I am not towing anything heavy so I really don't need the 4.10 rearend.

So here is my question: Is it cost effective to switch my 4.10 rearend to a 3.73? Is it a big job? Approximately how much does it cost?

Any input will be appreciated.

Billy
 

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Did you order it w/ 4:10's? Seems like most 2500's came in 3.73. You say 4x4 in your sig, you will have to change out both front and rear gears. I would chose a shop that specializes in rear ends. I have seen from $500 to $1000 for one diff but more on the higher end. I have seen a few guys that go w/ the 3.4? from 3.73 in the manauls to get better mileage.. Have not really seen the real results on that one yet.

It all depends on how long you will keep the truck.
 

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No, it is not cost effective. The gain in fuel efficiency will take FOREVER to break even with a gear change. Even if you do the work yourself. 3.73 isn't worth the time, though. Go straight to 3.55 or 3.42. I have 3.55's on 35's. :)

I don't know about that increase in fuel efficiency over time. Doesn't make sense to me. Driving style can have a BIG impact on efficiency, though.
 

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I would say the 4.10's are more verstile in most situations. I know you lose a little on the top end, but with only 25K on the truck, you aren't even really broken in yet. The 4.10's would be really nice if you do ever get a big trailer. I know the 3.73's are great for most, but with the auto, the 4.10's would keep the RPM's up a little more and put a little less stress on the driveline. Plus, you could always go with a taller tire to compensate for the increased gear. Swapping gear is never really going to pay off unless you keep them for a long time. Scotty
 
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