2000 Yukon Handling Issues - need help

[jla956]

My 2000 GMC Yukon has 254,000 miles. I just had the front end totally rebuilt, and at 173,000 miles I had the front and rear shocks replaced with factory parts - rear shocks are self-leveling air shocks. When i drive down the highway the Yukon handles great on a smooth road. However, the minute that I hit a bump in the road or a pothole, the vehicle starts rocking side to side. At times it seems like I will lose control and have to slow way down to stop the rocking motion.

When I got the front end rebuilt I thought that it might help this issue but it didn't. The steering and front-end handling are now great and the popping noise that it made when I slowly made a very tight turn is gone. So, the front end is good but now I need to know what to do to fix the rocking and loss of control issues. I see that it has coil springs at each tire and I was wondering if those could be worn out and need replacing? If so, should I replace them with factory springs or something else? Also, the tires are in decent shape and will probably last for another six months, so they can't be an issue with this - it's got to be something in the suspension. Thanks in advance for your suggestions and help as I plan on keeping this Yukon for quite a while longer. I just want to make sure that it's safe and comfortable to drive.

 

[MassHoe04]

If I had to guess, maybe the system that controls pressure to maintain the proper level with the shocks...

Does it level when load is added and go back down when load is removed?
If yes, doe it do it evenly?

No air leaks anywhere?

I would still suspect the unit that maintains level and balance to be one of the things to see if it is doing what it should.

 

[Fless]

The inquisition begins....

Did it act like this after the new shocks, or did it start recently? When?

What was done for the "totally rebuilt front end?" Any non-stock mods to the suspension besides the air shocks?

Are the front jounce stops in good shape and contacting the lower control arms?

Are the sway bar links, front and rear, in place and in good condition? Sway bar bushing condition at frame mount?

 

[jla956]

The inquisition begins....

Did it act like this after the new shocks, or did it start recently? When?

What was done for the "totally rebuilt front end?" Any non-stock mods to the suspension besides the air shocks?

Are the front jounce stops in good shape and contacting the lower control arms?

Are the sway bar links, front and rear, in place and in good condition? Sway bar bushing condition at frame mount?

I had them inspect the entire front end and let me know what was worn out and needed replacing. Here is what they did:

1. replace both lower ball joints
2. replaced right outer tie rod end
3. replaced Pittman Arm
4. Replaced Idler Arm and bracket
5. Removed all other front end parts, inspected, cleaned, and lubed
6. Align front end

The air shocks are stock - this model of Yukon has a factory Automatic Leveling System. When I put heavy items in the back, or hook up a trailer, you can hear the air pump engage.

I am not familiar with what all these parts are but will look them up to see if I can answer your question: front jounce stops, front and rear sway bar links, and sway bar frame mount bushings. There seems to be a YouTube video on everything so hopefully, I can find one that shows these items.

However, I would hope that the front jounce stops, front sway bar links, and front sway bar frame mount bushings are okay since I asked them to look over the front end. I have used this shop for years and have found them to be very reputable. Plus, I can't imagine them passing up the opportunity to earn money if something did in fact need replacing. Still, I would like to know what these items are so I can keep track of them for future wear.

 

[Fless]

I had them inspect the entire front end and let me know what was worn out and needed replacing. Here is what they did:

1. replace both lower ball joints
2. replaced right outer tie rod end
3. replaced Pittman Arm
4. Replaced Idler Arm and bracket
5. Removed all other front end parts, inspected, cleaned, and lubed
6. Align front end

The air shocks are stock - this model of Yukon has a factory Automatic Leveling System. When I put heavy items in the back, or hook up a trailer, you can hear the air pump engage.

I am not familiar with what all these parts are but will look them up to see if I can answer your question: front jounce stops, front and rear sway bar links, and sway bar frame mount bushings. There seems to be a YouTube video on everything so hopefully, I can find one that shows these items.

However, I would hope that the front jounce stops, front sway bar links, and front sway bar frame mount bushings are okay since I asked them to look over the front end. I have used this shop for years and have found them to be very reputable. Plus, I can't imagine them passing up the opportunity to earn money if something did in fact need replacing. Still, I would like to know what these items are so I can keep track of them for future wear.

Some videos mis-label the front jounce stops as "bump" stops, but the front ones should contact the lower control arms when the truck is at ride height (not on jack stands).

 

[exp500]

All the above is good info. Have mech test drive on your bumpy road and he will know you are serious. Sounds like you need a very thorough inspection, not a Guess.
After saying that, what is the condition of control arm bushings front and rear axle. Including pry bar tests everywhere. Rear axle loose feels horrible. You have something moving 1/16 inch or more somewhere. Could be a worn bolt or bolt hole, possibly torsion bars if it has never driven right.

 

[jla956]

The inquisition begins....

Did it act like this after the new shocks, or did it start recently? When?

What was done for the "totally rebuilt front end?" Any non-stock mods to the suspension besides the air shocks?

Are the front jounce stops in good shape and contacting the lower control arms?

Are the sway bar links, front and rear, in place and in good condition? Sway bar bushing condition at frame mount?

So, I have attached four photos - two of the left-side front end and two of the right-side. It appears that I have no jounce stops at all on either side but I will let you look at the photos to verify. I have also taken photos of the sway bar links and bushing, and the control bar arm area of each side.

Please look at those photos and see if anything looks out of order. I am done with this mechanical shop regarding this issue as they seem to be incompetent in that area. So, please look over these photos and let me know your suggestions/recommendations.

Since these are all original parts with 254,000 miles on them I'm guessing that it might be a good idea to just go ahead and replace the sway bar links and the sway bar bushings, along with the missing jounce stops. I haven't even looked at the rear end yet but I would also guess that it makes sense to replace those same items back there? Are there jounce stops in the rear, or are they just up front?

Also, what type of shop should I look to do this kind of work, and are the jounce stops something that I could do myself, or do you need specialized tools to install them. I am guessing that most of my side-to-side wobble is caused by these not being there and I would like to get those quickly fixed.

 

[jla956]

Photos of the rear suspension area. It appears that the two jounce stops are there but probably not in the best condition. It appears that I might be able to install the front ones fairly easily if I knew where to properly place a floor jack to create the needed space to slide the new ones in.

 

[Fless]

In addition to the control arm bushing inspection that @exp500 suggested:

The rear bump stops are just that; they protect from the frame bottoming out, and contact only when the truck is heavily loaded or goes over severe bumps. Your air shocks probably prevent that for the most part. But it wouldn't hurt to have good ones in place.

The missing front ones are easy enough and should be replaced; they're an integral part of the suspension and will help stablilize the ride. They must contact the lower control arm at ride height to work. See the video below. Just need a jack to raise the vehicle and a jackstand on the frame. Remove the wheel and install the new jounce stops. You can do one at a time.

You might start with that and see if it cures or at least helps the problem. It wouldn't hurt to replace those front sway bar links -- they look a bit weak -- but you'll need to have both front tires off the ground to do it (front suspension unloaded, both sides at the same time).

 

[iamdub]

+1 to what Sam listed.

Jounce stops work in conjunction with the springs. Without them, it's like having weaker springs. Insufficient spring strength for the amount of weight is essentially an overload. So, your front end will act overloaded, and that sounds exactly like what it's doing. Those similar-looking ones in the rear are bump stops, there to give the axle something soft to collide with instead of the frame.

Those are factory style sway bar end links, if not the original ones from the factory.. Regardless, they appear cruddy. Pretty much any aftermarket one is gonna be superior and with firmer material, like polyurethane or Delrin or, more likely, thermoplastic. Moog has nice ones. Don't forget the sway bar bushings on the frame. I'm sure the rear bushings and end links are just as cruddy. The good news is that all of this is cheap and an easy bolt-on.