Alignment done but... I was told it is 1/4 in lower on the left side.

No. That is not the case at all. More is not better just because and having a caster split just because isn't better either. Caster is related to the suspension geometry so "high" is relative to each individual vehicle. 4.5* is high for these trucks, especially when the spec is around 3*. I've driven and aligned hundreds of these trucks and 4.5* will drive like crap. So unless your lift kit says you need to set the caster at 4.5* because they've changed the angles and such, you need to set it at the factory spec.

Tozan said:

I have never heard of a "GM lean" nor seen it as being a normal thing...

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The GM Lean is real and it WILL GET YOU! It's everywhere with GM trucks from the old S-series to the trucks to the RWD SUvs. It's not noticed by many at stock or lifted heights but people go ******* after lowering cuz the "kit lowered the driver's side 1/2"-3/4" more". No, that side was always lower and just never noticed. I recall from my S-series days that people commonly ordered a spacer from Belltech to fix the lean when dropping their rides. It was just a polyurethane coil spring spacer sold individually.

I reduced the lean to almost nothing in my Xtreme by replacing the stock driver's side fuel tank that was located in front of the axle with one that went behind the axle, centered between the frame rails, relocating the battery to the rear and swapping the coils and leaves left-to-right.

91RS said:

No. That is not the case at all. More is not better just because and having a caster split just because isn't better either. Caster is related to the suspension geometry so "high" is relative to each individual vehicle. 4.5* is high for these trucks, especially when the spec is around 3*. I've driven and aligned hundreds of these trucks and 4.5* will drive like crap. So unless your lift kit says you need to set the caster at 4.5* because they've changed the angles and such, you need to set it at the factory spec.

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Do some research on caster because more in this case and in any case will certainly make it more stable. This is true with cars, motorcycles and even shopping carts. More caster makes anything want to go straight with more stability. You said it would be less stable and that is not the case at all geometry and physics does not support that statement at all.. 4.5 is driving just fine right now.. On the road and off road at high speeds so don't tell me it will drive like crap I already know what it drives like..

Also do you know the stock specs and tolerance?

So far as right and left not being the same look at the post below this guy (you) said the caster should be... You also stated 4.5 +/- 1 Now in modern or old math that means it could be as high as 5.5 and still be in specs... Also if you actually read my post you would see I stated " The company who made the lift RECOMMENDS 4.5

91RS said:

Actually it looks like wheel size didn't matter on a Tahoe, only Avalanche. Here are the specs for your K1500 2003 Tahoe (4x4):

Caster:
L: 3.50° ± 1.00°
R: 4.50° ± 1.00°
Cross Caster (L-R): -1.00° ± 0.50°
Camber: +0.25° ± 0.50°
Cross Camber (L-R): 0.00° ± 0.50°
Total Toe: +0.10° ± 0.20°
Steering Wheel Angle: -1.0° ± 3.5°

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Plus since you wanted to post resumes here is my short list. I am a mechanical engineer, I was a designer for motorcycles, I also did the chassis set ups for the National factory Suzuki race teams as well as thousands of others in our chassis shop. I specialized in automotive alignment as far back 1976 and I certainly know what caster, camber, toe and thrust angles are and what they do.

So thank you for your comments but I really don't need them anymore.

I don't need to research anything, I'm well aware of what the measurements do. I didn't say anywhere it would be less stable, I said it will be touchy at speed (and at speed is what you were concerned with) and then said it will drive like crap (because of being touchy). And I say this because I literally know from driving hundreds of GMT900's before/after doing alignments where people have cranked up the caster trying to make the camber "green" instead of setting to specs. I'm not just pulling stuff out of my tail. I also said unless your lift kit recommends that because the lift has changed the geometry of the suspension. I did miss your other post where you said they recommend 4.5* but either way, I still think 4.5* is a bit too high but it's your truck so do what you want.

If that really is a quote from me, it was from a thread in the GMT800 forum because it clearly says 2003 Tahoe which is a completely different body style and has different specs...

So to answer your question, check all the bushings for being worn and that the pins for the adjustment cams haven't fallen out of the frame. You may have to accept a little negative camber to get the caster where you want it and make the other side match.