1500hd/2500hd axle question

[chevystudz7105]

i have an 03 crew cab  1500hd  and  kind of wishing  i had the 4.10 gears  instead of 3.73.  well i ran across a guy on craigslist  that has a rear axle and front diff out of an 05  that are 4.10.   i know  both will bolt right up  into my truck  without a problem  but im wondering  if i will have issues with my drive shaft.  my truck has a 2 piece rear drive shaft  and im not  100%  but i believe the 2500hd has a 1 piece drive shaft (please correct me if im wrong on this)  only reason i thought they had a 1 is my buddy has a crew cab gmc 2500  and it is a one piece drive shaft in his truck.    

doesnt seem like a bad deal and since i run a lil bigger tire  i figured  the 4.10s  might help me get a lil better  mileage.  if not that  it will atleast help out a lil when it comes to hauling the bogger around.

thanks for any help/info

[millser]

wiyh 4.10s you will get around 6-7 pulling if its got the 6.0  and 10 driveing

[Crazymays77]

Well I have a 02 gmc Sierra 2500hd. Ext cab long box has a two pc driveshaft. I have the 8.1 with 4.10 gears I get 10 mpgs empty.

[Crazymays77]

Going from 3.73 to 4.10 will be worse mpgs u will be running higher rpms

[J.C.]

Going from 3.73 to 4.10 will be worse mpgs u will be running higher rpms

hes runnin a little bigger tire then stock, might be ok?

[ballistics-10]

I have a 2003 2500hd with 8.1l and 5 speed allison trans 4.10 gears and I get 16mpg empty and about 10 towing

[millser]

I have a 2003 2500hd with 8.1l and 5 speed allison trans 4.10 gears and I get 16mpg empty and about 10 towing

my 03 8.1 5speed allison 4.10s get 7 pulling 9-10 empty

[ballistics-10]

what size tire u running millser?

[betterbeaters]

man the 8.1 I drove got 6mpg! 


bigger tires will work better with 4.10s and it should pull sweet!

[7387chevynut]

not 100% sure, but..........your engine/computer might be (set) calibrated for 3.73............and throwing 4.10 gears in there might throw some stuff off.......

[Crazymays77]

im running 265/75/16's had 245 75 16's before. just did a tune up but have not checked mpg since then cant afford to fill it up to check it

[Crazymays77]

bigmike what size tires u running. wonder why i am getting less then you.

[ToughBowtieTruck]

Yeah computer will have to be told of the new gear size, otherwise speedometer and speed-related systems won't operate properly. 1 piece and 2 piece shafts are odd really, sometimes it just depends on the options on the truck. My '77 3/4 ton standard cab long box 4x4 has a 2 piece drive shaft in it, when a lot of them had one piece.

4.10s won't give you hardly any better mileage than the 3.73s, the engine just runs a little higher rpms, and you get more torque on the low-end with 4.10s. The only time it would really matter is if the truck will end up with less load on the engine--meaning you don't have to push the pedal as far to maintain speed (that is what ultimately burns fuel, how far the throttle plate is open when cruising, which tells the injectors how much fuel to match air intake with). Once you're rolling on flat ground you can hardly tell the difference . . . especially since when you are sacrificing less engine load for higher rpms.

And as far as towing is concerned, My 2000 Silverado 1500 with the 5.3 is rated for 8,000 lbs trailer weight, as I have 4.10 gears in mine. The 3.73 version, is rated for 7,500 lbs worth of trailer. Now assuming you "stick" to the legal tow limits set by the manufacturer, you only gain 500 lbs towing ability "per-say" after doing all the work swapping parts and updating the computer. Something to ponder.

Also, I get about 15mpg with mixed driving empty with my 2000 and 4.10 gears,  with 265/75/16 Cooper Discoverer ATRs rolling under it.

[chevystudz7105]

i have a programmer for this truck so its not a problem to  put in that i have 4.10 gears  instead of the 3.73 if i were to make the switch.   

each company truck at my work  (3 ext cab long box and 1 crew cab short box)  are all 2500hds trucks  and all are 2wd except 1  and they all get about the same mileage 12.5  except the one that seems to run better then all of them  it gets about 10 which is a 2wd.   

i guess i thought since i run a bigger tire then what comes on these trucks that maybe the 4.10 gears  would help out.  depending on how fast i drive  i get  8 or 9 hauling my other truck and 11  11.5 empty.     i guess when i sit down and think about it  its not really worth it to spend the money and buy the axles

[Trucker]

i have a 2002 gmc 2500 hd 6.0 and 4:10 gears and 265 75 16 tires i get 14 on the highway and 12 around town emty i have not used it to haul any thing yet but i turn 2600 rpm at 75 on the highway empty

[ride n dirty]

I have 03 1500hd with 265 75 16 get 11.6 empty between 9 9 1/2 pulling 30' camper not that bad got 4 10 gears

[ToughBowtieTruck]

I have 03 1500hd with 265 75 16 get 11.6 empty between 9 9 1/2 pulling 30' camper not that bad got 4 10 gears

Way to revive the dead thread!