2004 trailblazer lift kit

[Thatguy]

what all do I need to do to get 33" tires under this truck what parts and brands do you recommend

[med71]

I was just in your position so I’ll give you my thoughts. This site is a wealth of information; it’s not as active anymore, but there is a lot of knowledge in the posts if you search for it. I got everything I needed to know by searching this site.

So to answer your question: There are a lot of different ways to lift your Trailblazer with different spacer and spring combinations, and a lot of those choices depend on what you want to do with it. I went the old school route with heavy Moog springs and an RC kit so I don’t know much about the adjustable bilsteins and some of the new ways of doing it. Your spring selection will definitely add lift so you must calculate that as well. For instance my Moog 81114 adds 1” and the 81112 adds .5; stock is 81110.

Your max suspension lift is 3/2 (front/back) 1.25” difference front/back is level. Your upper steering knuckle clearance is restricted to a 30.5” tire without spacers. Your wheel stud length requires 1.5” spacer without shaving down studs. The stock 17x7 wheels have a 6” backspace. If you go to aftermarket wheels, you need to calculate your wheel and backspace. The 6x5 wheel is annoying so you will need adapters if you want to open up your selection of the standard 6x5.5 GM wheels.

If you do a 3/2 lift, you will need to flip your upper control arms; its easy. Another issue is that the rear axle isn't centered after the lift. I haven't done this yet, but it needs an adjustable panhard rod.

As far as what you can do with the 3/2 suspension lift. I have 265/70/17 General Grabber ATs on it. I had to hammer down the rear bracket for the liner/ground effect attach point. I had to cut away the ground effect attach point and attach it to the fender instead. I also had to grind the lower lip of the front bumper and move the attach bracket. I made these changes working through the full steering and articulation range of motion. I did not have to do anything with the fender sheet metal. 33” tires of any size will require horizontal clearancing of the sheet metal regardless of lift. You could probably stuff a set of 33s in the 255/75/17 range with some minor cutting. A set like my 285/75/16 Mickey Thompsons on my Suburban would require a lot of cutting. Based on what I can see with mine, I would do a 2” body lift with 33s and a 3” with 35s (in addition to the suspension lift.)

Also, you need to check your gears. Is yours a 3.73 code or a 3.42 code? From what I read, 33s with 3.42s will cook the transmission on the Trailblazer/Envoy, and 32s is really pushing it if you have a good trans cooler. From my experience 3.73 gears is about as high as I would go on any trail rig with 33s. I really prefer to have 4.10s with 33s and 4.56 with 35s as my minimum standard.

You will definitely need the radiator skid plate ASAP because it is horribly exposed. Also, the oil and trans need to be done too.

I think that pretty much sums up what you need to start the process. It is definitely one that requires homework because there isn’t a kit that has all the parts you need. It is an a la carte selection of different things that need to work together.

Edit: One last thing I forgot. There really isn't any locker support for our IFS anymore. Also, check your rear axle; I picked up a salvage yard 8.6 G80 axle for mine.

[Diacom]

Welcome Jason,

Mark pretty much gave a good over-view in his post. Look over the site as much as possible and if you have further questions hit up the Facebook page as it will get responses a bit quicker.

Enjoy your TB however you decide to go.

[TBext17]

so we can't find front lockers anymore

I was just in your position so I’ll give you my thoughts. This site is a wealth of information; it’s not as active anymore, but there is a lot of knowledge in the posts if you search for it. I got everything I needed to know by searching this site.

So to answer your question: There are a lot of different ways to lift your Trailblazer with different spacer and spring combinations, and a lot of those choices depend on what you want to do with it. I went the old school route with heavy Moog springs and an RC kit so I don’t know much about the adjustable bilsteins and some of the new ways of doing it. Your spring selection will definitely add lift so you must calculate that as well. For instance my Moog 81114 adds 1” and the 81112 adds .5; stock is 81110.

Your max suspension lift is 3/2 (front/back) 1.25” difference front/back is level. Your upper steering knuckle clearance is restricted to a 30.5” tire without spacers. Your wheel stud length requires 1.5” spacer without shaving down studs. The stock 17x7 wheels have a 6” backspace. If you go to aftermarket wheels, you need to calculate your wheel and backspace. The 6x5 wheel is annoying so you will need adapters if you want to open up your selection of the standard 6x5.5 GM wheels.

If you do a 3/2 lift, you will need to flip your upper control arms; its easy. Another issue is that the rear axle isn't centered after the lift. I haven't done this yet, but it needs an adjustable panhard rod.

As far as what you can do with the 3/2 suspension lift. I have 265/70/17 General Grabber ATs on it. I had to hammer down the rear bracket for the liner/ground effect attach point. I had to cut away the ground effect attach point and attach it to the fender instead. I also had to grind the lower lip of the front bumper and move the attach bracket. I made these changes working through the full steering and articulation range of motion. I did not have to do anything with the fender sheet metal. 33” tires of any size will require horizontal clearancing of the sheet metal regardless of lift. You could probably stuff a set of 33s in the 255/75/17 range with some minor cutting. A set like my 285/75/16 Mickey Thompsons on my Suburban would require a lot of cutting. Based on what I can see with mine, I would do a 2” body lift with 33s and a 3” with 35s (in addition to the suspension lift.)

Also, you need to check your gears. Is yours a 3.73 code or a 3.42 code? From what I read, 33s with 3.42s will cook the transmission on the Trailblazer/Envoy, and 32s is really pushing it if you have a good trans cooler. From my experience 3.73 gears is about as high as I would go on any trail rig with 33s. I really prefer to have 4.10s with 33s and 4.56 with 35s as my minimum standard.

You will definitely need the radiator skid plate ASAP because it is horribly exposed. Also, the oil and trans need to be done too.

I think that pretty much sums up what you need to start the process. It is definitely one that requires homework because there isn’t a kit that has all the parts you need. It is an a la carte selection of different things that need to work together.

Edit: One last thing I forgot. There really isn't any locker support for our IFS anymore. Also, check your rear axle; I picked up a salvage yard 8.6 G80 axle for mine.