6" inch suspension lift or 3" body

99sierraz71 · May 31, 2004

I'll give you a little info before I ask my question, I have a 1999 gmc sierra z71 4x4 , I was wondering if someone

could tell me what I would need to change with a 6" inch suspension lift besides the bolt on kit,

eg; diff gears, tranny, drive shaft, stuff that they don't tell you oin the kit,

and also tell me what is going to cause me less trouble in the long run a 6" suspension lift or doing

a 3" lift with blocks then doing a 3" body lift. I'm not sure which way to go so some insite would be

much appreciated. And what would be required for larger tires, lets say 36" tires. would you need to

change your gears for them.

thanks

99sierraz71

snoman · May 31, 2004

You will need to change gears for sure, at least 4.56 but a 5.13 would be better (4.88 would probaly be a ideal compromize) and 36's would be exceeding axle capacities in the 1/2 ton truck. (33's is a pretty safe max and 35's are pushing it) If you do not install lockers and do not abuse it you might get by okay. A 3/4 ton truck is a better basis for 36's or 38's. You might look into getting a 9.25 IFS from a 3/4 ton at a bone yard to swap your out axles and all as I am more concern about it than rear 10 bolt with those tires. (your current rear axle is a bit strong than the 8.25 IFS you have in the front end now)

AZ-Z71 · June 1, 2004

I have both on mine, a six inch suspension lift and a 3" body lift. With a 3" body lift you probably will not be able to put 36" on with out the suspension lift. On a suspension lift I think the smallest you will be able to go would be a 4" suspension lift. Currently mine looks really good with that set up and 35's. I'm not sure but looking at mine, 36's look like they would require a little bit more cutting of the actual bumper and maybe a slight fender trim to get them to work out.

If going with 36" you probably want the 6" suspension lifft and a 3" body lift. Also going with that size tire you would definately need a re-gearing of both the front and rear differential. Someone told me that a 4.56 would work up to the 37" tire size.

Depending on which lift you go with will dictate if you will need to change the front shaft for the autotract 4x4. Some lifts you need it some you don't. The Fabtech one didn't. Check this site for information on several different lifts. They also tell you a little bit about each one and tell you if you need the front shaft or not.

Rocky Mountain Suspension

Obviously you would also have to change your wheel, for stockers will no longer work with that size tire. Also check with the lift manufactures, some don't recommend using larger than 35" tires.