2012 XL Denali AWD steering shake over large bumps.

[dkad260]

This is something I noticed when I bought this used 2 years ago, doesn't happen over light to medium bumps, but at hwy speeds over a good bump, the steering wheel will shake back and forth a couple times then quickly settle.

What I have done since purchase is new Defender LTX, new OE front diff mount brackets, new hub and bearings, new brake calipers, rotors, pads, and new OE strut cartridges. I had an alignment done with the new tires and also a week ago.

I do have the OE 22" wheels if that matters.

The upper and lower ball joints are good.

There is no looseness of the outer tie rods, they are tight.

I don't notice any wobble or play in the steering rods, and the steering is tight when driving, no dead spot on center.

My only thought is the mass of the wheel/tires just overcomes the steering for a moment. So should this never happen or normal for the GMT900?

Maybe the rack is slightly worn and only shows it's face with a stiff jolt/tremor of a bump at hwy speeds. This shake is very quick, just a couple slight back and forth movements of the wheel and it settles, nothing like a death wobble or a constant spring oscillation.

The steering rack mounts are tight also.

I will try to get a video in the coming days.

 

[B-train]

I'd say it's probably normal for the age. I'd also suggest avoiding large bumps at speed....LOL

 

[wjburken]

I’m assuming you have checked the sway bar links in front as well?

Have you had the alignment checked lately?

Might check out the rear suspension components as well like the rear sway bar, panhard bar, link arm bushings, etc. Could be that the rear end is bouncing around and your feeling it in the steering wheel. May not be that, but worth a check.

 

[Geotrash]

This is something I noticed when I bought this used 2 years ago, doesn't happen over light to medium bumps, but at hwy speeds over a good bump, the steering wheel will shake back and forth a couple times then quickly settle.

What I have done since purchase is new Defender LTX, new OE front diff mount brackets, new hub and bearings, new brake calipers, rotors, pads, and new OE strut cartridges. I had an alignment done with the new tires and also a week ago.

I do have the OE 22" wheels if that matters.

The upper and lower ball joints are good.

There is no looseness of the outer tie rods, they are tight.

I don't notice any wobble or play in the steering rods, and the steering is tight when driving, no dead spot on center.

My only thought is the mass of the wheel/tires just overcomes the steering for a moment. So should this never happen or normal for the GMT900?

Maybe the rack is slightly worn and only shows it's face with a stiff jolt/tremor of a bump at hwy speeds. This shake is very quick, just a couple slight back and forth movements of the wheel and it settles, nothing like a death wobble or a constant spring oscillation.

The steering rack mounts are tight also.

I will try to get a video in the coming days.

+1 to checking the sway bar links and mounts. Also, some folks have had trouble with the steering rack slipping in its mounts. One fix I saw was to crush a rubber coil spring mount ring between the rack and the frame crossmember. Another was to buy new rack mount bushings from Febest.

 

[dkad260]

I will check the rack bushings.

Would these need to be pressed in/out?

 

[Joseph Garcia]

I don't know what the source of your issue is, but I can tell you that my 07 Yukon XL Denali has the Michelin Defender tires, and there is no steering wheel shake when I go over bumps.

 

[dkad260]

I don't know what the source of your issue is, but I can tell you that my 07 Yukon XL Denali has the Michelin Defender tires, and there is no steering wheel shake when I go over bumps.

I agree it's likely not the tires, I just wanted to document what I had for sake of discussion.

What I get is a quick back and forth movement and it quickly settles. This is over something like a sharp transition in the road, where the concrete overpass meets the asphalt and the surfaces aren't level....it's a fairly sharp bump to make this happen.

 

[Geotrash]

I agree it's likely not the tires, I just wanted to document what I had for sake of discussion.

What I get is a quick back and forth movement and it quickly settles. This is over something like a sharp transition in the road, where the concrete overpass meets the asphalt and the surfaces aren't level....it's a fairly sharp bump to make this happen.

I think that may actually be normal, the way you’re describing it.

 

[Geotrash]

I will check the rack bushings.

Would these need to be pressed in/out?

Yes, I believe so.

 

[Billeickmann]

My 2012 Tahoe LS 4WD started doing the same thing last year with about 62,000 miles. It does it with Mich. snow tires or Bridge. All Seasons. Took it in to a good front end shop and he said he has seen it before, but was not sure if it was the steering or struts. He said to let it go until it was a little worse and he would look again. No charge. I'm about to go back.

 

[swathdiver]

If the wheels and tires and steering and suspension are in good order this can be alleviated by a good alignment technician. You'll want the caster in the 3s with a 3-4 degree spread for a sportier feel and more control over bumps. Something like 3.2 Left and 3.6 Right or even 3.6 Left and 3.9 Right.

Do some googling for a better explanation on how these settings affect the steering and handling.

 

[petethepug]

Thread 'NNBS POLY Susp Bushings - Put em Where They Belong'
https://www.tahoeyukonforum.com/threads/nnbs-poly-susp-bushings-put-em-where-they-belong.111086/
There's not much in poly suspension bushings for the 07-14 NNBS. It makes sense though because there's only a few key areas where they'd do more for the ride instead of muck it up with bump steer. Sway bars are the first to have aftermarket options. It's proven they don't wear and superior in performance, especially if exposed to petroleum products.

Energy shows they have a transmission mount for our 08 Yukon Denali. That's pretty much worthless unless they made a matched set for the motor too. Poly and (oem) rubber bushes don't feel good or work well together for very long.

Here's' an Alldata post to help diagnose if you've got issues that need tissues on your:

https://www.brakeandfrontend.com/gm-simple-steering-noise-fix/

• 2007-‘13 Cadillac Escalade
• 2007-‘13 Chevrolet Avalanche, Silverado, Tahoe
• 2007-‘13 GMC Sierra, Yukon



I wanted to create a parking place for poly bushings for the NNBS as they're developed. The one key product I was looking for, but wasn't available when I needed it was, a poly steering rack bushing. They're susceptible to the usual bushing killers, heat, oil, coolant, p/s fluid and whatever is kicked up from the road.

A Dude here in SoCal came up with a fix for the venerable p/s bushing made of poly that's cut and slides in as a direct replacement. The two oem rubber bushing on the d/s aren't suitable for poly because they'd transmit too much road feel to the wheel. GM has not done it yet, but the solution would be to create a HD rubber bushing with more OEM material loaded into the same space.

Until GM or Dorman makes a set of HD power steering mounts for the driver side, Ricochet created a simple solution to keep those two bushes from destructing themselves. He added a steel bracket that takes up the void where there is no bushing material. This limits the deflection that the rack can make into the area where the oem GM bushing has no material.

Prior to my recent AC Delco reman rack replacement, I didn't know about this product. That same rack in the Denali is moaning. Despite being purged, burped and checked all other potential causes, it looks like I got a bad reman rack, or one that sat too long on the shelf. I may be installing this into the replacement rack if I can't figure out why its moaning.

I've put out a request for more info on the product and will keep everyone updated.

Fits Chevrolet Silverado Tahoe Steering Rack Bushing Set Polyurethane 19330568 | eBay

New Rack and pinion bushing kit. This bracket installs in minutes! We also include a heavy duty polyurethane extra wide bushing for the passenger side of the rack. Made in the USA by Ricochet Polyurethane Technologies.

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