Chevy gear ratio change?
 

I have a '04 Chevy 2500HD with 6.0L/Auto/4.10 rear. I wonder if changing the rear to a 3.73 would be practical. I'm only towing 5-6K and was thinking with a 3.73 it would be a little better for every day use. The MPG sucks! I know the 3.73 was available in the regular 2500 but not the 2500HD.

Does this sound like a good idea? How much would it cost? Would I see a noticable improvement? My old truck was a 1500 5.3L/auto/3.73 and it towed good and got decent MPG.

I know, don't say it.... YOU SHOULD OF GOT A DEISEL!

Re: Chevy gear ratio change?
 

You would gain very little MPG when empty, and it would drop dramatically when towing. Not to mention, there's a better chance of ring & pinion failure along with transfercase and transmission failure. Plus, the money it would cost to change out the gears...
If you got 2 MPG better it would take you about 4 years to make up the cost of the gear change.

Re: Chevy gear ratio change?
 

Thanks, I figured it would not be practical to swap. I noticed that on the hwy at 70 MPH my 2500 is at about 2500 RPMs. It seemed like my 1500 w5.3/3.73 was below 2000 RPMs at 70 MPH.

Re: Chevy gear ratio change?
 

Its only a 9.3% percent difference (3.73 divided by 4.11-90.75% so if you were turning 2500 it would only drop 250rpm's. You could achieve a 10 % drop by going from 30" tires to 33" tires. Hd's use a special 11.5 inch ring and pinion,the duramaxes came with 3,73 gears so the gears are available but the swap will be very exspensive,i'd probably charge 1500$ at my shop parts and labor and the dealer would easily be double that so it would take you 100,000 miles of driving just to break even,Smitty

Re: Chevy gear ratio change?
 

Hey Articfriends,

Your math makes sense. I think I had bigger tires on my old truck. That makes up the difference in rpms.

Dave M.