Bigger Differential

[yc7998]

ive got a 01 sierra with a 6" suspension and 3" body with 35's...im trying to figure out what kind of rear axle and gear ratio i have stock so that i can make the necessary improvements

[dietz4ibanez]

score

[97SierraGMC]

Count the bolts...

[97SierraGMC]

with a 6" suspension and 3" body with 35's

 

not exactly sure how that helps determine what axle you have?????????????????????

[J-man67]

Count the bolts on the rear diff. I'm sure its a 10 bolt with either 3.73's or 4.10's. They are weaker then others, and when you add bigger wheels/tires, even worse. I have one, but presently looking for a 14 bolt off of a Vmax. Anyway, there are TONS of things you could do back there. Search for a 14 bolt out of a HD truck with a similar year. Junk yards are a good source. I would do a 4.56 if you plan to keep 35's, 4.88's if you plan to go up to a 37. Also add a Detroit Trutrac.

 

Edit: Just saw your other post. What do you plan on doing with the truck? If you are just going to drive it solely on the street then you should be fine with your 10 bolt and new gears. Since you have the 4.8, you MIGHT have the 3.42 gears. If jumping to 35's I would def at least go with new 4.56 gears.