4.10 to 4.88?

[zen720]

I have a 2015 2500HD with a 6" lift and 35" tires. I do pull often with the truck and was considering going to 4.88 gears. Has anyone with a similar setup gone to 4.88s and your thoughts.

[SierraHD17]

I run a 33.5" tall tire and went to 4.56 in my 2017  liter HD.  It started life with 3.73 so it benefitted more than a 4.10 one but still.  I would not hesitate for 4.88 with a 35.  Tachs 2100 at 70 mph and the mileage improves slightly from not lugging in 6th.

[zen720]

Mine came with the 4.10s. It is not bad, but pulling my toy hauler I feel it could use a little better gearing to keep trans temp down and more power for hills.

[SierraHD17]

They all do... just mine is an oddity because it was ordered under the fleet program.  Even with 4.10 gears these trucks are severely undergeared in stock form.  4.56 should be a factory option like it used to be in the 90s... Pulling trailer is pretty effortless with my truck now.  4.88 with a 35 will be roughly the same overall gear I have with the slightly smaller tire.  I was going to put 35s on mine as I have miles of room but I like how it drives and will be leaving the tire size I have on it.

[i82much]

I would go with a 4.89, just to be certain it isn’t undergeared.  4.88 might be a touch too tall.

[SierraHD17]

1 hour ago, i82much said:

I would go with a 4.89, just to be certain it isn’t undergeared.  4.88 might be a touch too tall.

 Funny guy!  Being serious 5.13 would be alright too but 4.88 should do the trick.