I was driving behind my truck and noticed that it was dogwalking/side tracking. I took the truck to a shop that is a suspension shop. Thi is all they do. I have used this shop for years and I deal directly with the owner who is a great man. He disassembled the rear suspension twice and said there was nothing wrong in the rear. The front suspension needed a few parts (all Moog parts, idler arm, pitman arm, both tie rod ends). He installed the new parts.I then immediately took the truck for an alignment at Belle Tire. The truck still dog walked/side tracked.I had the suspension shop examine the truck again and he said everything was fine. I had the alignment redone today.The truck still dog walks. As the road contours change the rear end has some lateral play that is seen as I drive behind the truck.Also, the truck been empty during all of this but during the warm season the truck is loaded with a 3000# truck camper. I have one extra leaf per side in the rear. I have the Bilstein shocks, that for the rear, are specifically designed for truck camper use. I have Helwig sway bars front and rear. They are properly installed. I talked to Helwig and they nice tech support man said my sway bars are installed properly and that the sway bars can't be the problem.Questions:1. What else needs to be checked to determine why the truck dog tracks and has lateral play in the rear?2. I need to know if carrying a 3000# truck camper with a dog tracking condition it potentially dangerous. Is it and if so why?I really appreciate your thoughts, comments, insight, and experience.God Bless You.Sincerely, Jeff Fox

Best check axle distance 1st, meaning from center point of axle/wheels. After that I would check that the axles are square to themselves by doing an X measurement.About traveling with a load, the bad would be is the tread on the tires are not running true down the road, meaning that your tread is contacting the pavement at a diagonal motion, probably will cause premature tire heating and wear, creating potential blow out conditions.

Did you just get new tires? if so, sometimes this happens when the tires are new. OR< one or more may have a belt that is slipped, and you need new tires. I di dnot see that tires were checked. Marty

The tires are Michelin LTX AT2 10 ply and have about 3,000 miles on them. I think they are in good shape because they drive nicely. I know from experience what a shifted belt in a tire feels like. Thanks for asking about the tires.

Some of the older vehicles ( don't know if it is still true ) the rear axles ( wheels ) were narrower than the front to allow them to track true when turning a curve. If you were following behind and tried to align the rear with the front, it would appear that it was " dog walking " perhaps this is what you are seeing ?If this is the case, the alignment guy that you first went to, should have known this.

Dog walking has to be the rear suspension out of line. If the front was out, then steering would correct it.As suggested, measure axle center point on each side from a corresponding equivalent point on each side.Often axles have moved on the spring, or even a broken leaf, but your suspension guys should have found that.

Is this a dangerous situation? | Good Sam Community

46 Replies

CA_Traveler
Explorer III
Feb 24, 2015
OK I missed the .01 thrust angle. Have someone drive the vehicle. You sit dead in the center of a second vehicle (rear seat etc) and have that driver move side to side while you observe. Say nothing. Then repeat the observation with the other two persons and then compare notes. Then you'll have 1, 2 or 3 opinions. :B
GWolfe
Explorer
Feb 24, 2015
ib516 wrote:
jdgreen42 wrote:
Some of the older vehicles ( don't know if it is still true ) the rear axles ( wheels ) were narrower than the front to allow them to track true when turning a curve. If you were following behind and tried to align the rear with the front, it would appear that it was " dog walking " perhaps this is what you are seeing ?If this is the case, the alignment guy that you first went to, should have known this.

This ^^

I think it is this as well.
schlep1967
Nomad
Feb 24, 2015
My mechanic has a diagram showing this same scenario up in the waiting area of his garage. It shows that the tires are all pointed in the same direction but the front and rear do not track the same. Other than overall width of vehicle when sitting on the road it really does not hurt anything. Because some vehicles are not adjustable at both ends you have to adjust one to match the other. This doesn't mean it is the best scenario, it just means it is the one you are stuck with without spending a lot of money to make it "look" right.
pf32450
Explorer
Feb 24, 2015
Have you had the Frame checked for Square?
Have you owned the truck since new? Sounds like the frame is triangulated.

My thoughts have the frame checked!
dodge_guy
Explorer II
Feb 24, 2015
Well, with a .01 thrust angle I'm going with an optical illusion due to the front track being wider than the rear track. GM trucks had the rear axle that was narrower than the front.
psuce
Explorer
Feb 24, 2015
Does it have a full floater rear end? If so, I did not see it mentioned but did you have the axle hub(s) checked to make sure the lock nuts are tight on the hubs? Not the lug nuts on the wheels, but the nuts inside the hub that hold the hub onto the axle housing (you would need to pull axles to check). If these were loose the hub(s) would walk side to side when turning left/right. You would probably also have some fluid leaking from around the inner hub seals if this was the case though...

One other thing I have seen, you said the center bolt was replaced, was the corresponding "hole" in the cast axle perch ok? I have seen them rust/rot to the point where the bolt was sloppy in the hole and no longer aligned properly. However with the u-bolts tightened it would more than likely not have lateral movement, it would just not track straight.
mabynack
Explorer II
Feb 24, 2015
Dog tracking occurs when the rear end isn't aligned with the front end. It's normally caused by one of two things. One is the rear end has shifted on one side and the second cause is a bent frame. You can measure the distance between the center of the front wheel to the center of the rear wheel on the same side. Both sides should be pretty much exact. Look at the frame and mounting areas on the rear suspension for the rear end to check for damage.
Sport45
Explorer II
Feb 24, 2015
I agree that the appearance of crabbing may be an optical illusion due to the difference in track width.

But the OP seems to be saying the rear axle is shifting side to side when driving. I don't see how something like that could get past a suspension shop rebuild and later inspection, but it certainly isn't right. But then it's hard to tell if he's saying the axle moves relative to the truck (my interpretation) or the rear of the truck moves relative to the front (the illusion).

jefffoxsr wrote:
There is lateral movement in the rear of the truck when the road changes so something is wrong. It should not be doing this

If the rear was moving relative to the front on a scale large enough to notice from a following vehicle I'd think the driver would notice an awfully squirrelly ride.
BurbMan
Explorer II
Feb 24, 2015
jefffoxsr wrote:
I have in front of me the print out from the alignment that was done today.....Thrust angle shows 0.01 degrees.

Guys just about every new alignment machine does a 4 wheel alignment. However, there are no specs loaded in the database because GM lists these rear suspensions as non-adjustable. In other words, if the axles and springs are in the right place, it is considered aligned. There are no camber/caster/toe adjustments like you see on vehicles with IRS, like our 05 Dodge Magnum.

The alignment machine did measure and report the thrust angle at .01* as the OP noted.

I agree that crabbing is caused by rear axle mis-alignment, but the fact that that the suspension diagnosis and the alignment numbers don't bear that out leads me to go with the optical illusion diagnosis.
dodge_guy
Explorer II
Feb 24, 2015
Did anyone actually measure the rear suspension on the alignment rack? I`m guessing not, because the Thrust Angle would show which way it was off. it can be fixed by a shop that knows what they are doing.

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Is this a dangerous situation?

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