Diagnosing Steering Wheel Kickback Over Bumps and Bad Pavement

[sc470]

Hello all.

I have a 2004 GX470 with 90k on the odo.
I'm the second owner, the first owner seems to have taken care of the truck.

Ever since I got it I've noticed the steering wheel rotate by itself when going over road bumps and holes. I did a complete front suspension refresh including LCAs and UCAs with ball joints. I also have a Dobinsons 2" lift currently. New front swaybar endlinks. The steering rack seemed loose and was leaking, so I have a new OEM steering rack as well (comes with inner and outer tie rods). The two intermediate steering shafts are brand new as well.
I am now wondering what it could be. During my investigation, I pulled the steering column and checked for looseness. The column shafts appear fine and tight, I have no slop in the steering wheel, any frre play is within spec. The steering is very responsive, I turn the wheel a couple of millimeters and the wheels follow. Steering is not heavy. I tested the wheel bearings for play (12-6 test), they are solid. Lugs always torqued to spec.

The steering wheel showed kickback with stock tire size, has it now with 275s. So if it's not the control arms, tire size, shocks, steering rack or tie rods, intermediate steering shafts, or the steering column, what could it be?

 

[OG Zuninja]

How's your alignment? Do you have a printout of it after all those parts were replaced?

 

[sc470]

How's your alignment? Do you have a printout of it after all those parts were replaced?

Here it is. Actually had multiple ones done. Same result. The first one is the latest.

 

[vipergrhd]

Try messing with your tire pressure, go from low 30's to about 40 and see how it reacts. Your alignment readings are dead on your SAI and IA are good to.

 

[sc470]

Try messing with your tire pressure, go from low 30's to about 40 and see how it reacts. Your alignment readings are dead on your SAI and IA are good to.

I'll try that and report back.

 

[OG Zuninja]

Try messing with your tire pressure, go from low 30's to about 40 and see how it reacts. Your alignment readings are dead on your SAI and IA are good to.

I'm no expert but the SAI being as different as it is from side to side is concerning to me. Granted, it's "within spec" but there's a good difference between each side. Maybe it is a tire pressure issue but if he's experienced this issue with stock tire size and now the larger tire, it may not be tire pressure related.

Since it was brought up, @sc470 what tires are you running and what load index are those tires?

 

[sc470]

I'm no expert but the SAI being as different as it is from side to side is concerning to me. Granted, it's "within spec" but there's a good difference between each side. Maybe it is a tire pressure issue but if he's experienced this issue with stock tire size and now the larger tire, it may not be tire pressure related.

Since it was brought up, @sc470 what tires are you running and what load index are those tires?

I run Falken Wildpeak AT4W 275/70R17 C rated, 114/110S.

 

[OG Zuninja]

Okay. I had to go back and give your first post another look because this isn't adding up.

Ever since I got it I've noticed the steering wheel rotate by itself when going over road bumps and holes.

At what speeds are you noticing this? When this kickback happens, do your rear tires go over these same bumps/holes and give the sensation of the rig "bouncing" to one side? What kind of road bumps?

If you've made other posts about this, I haven't seen them so I'll ask this: is this your first body on frame vehicle?

 

[sc470]

Okay. I had to go back and give your first post another look because this isn't adding up.

At what speeds are you noticing this? When this kickback happens, do your rear tires go over these same bumps/holes and give the sensation of the rig "bouncing" to one side? What kind of road bumps?

If you've made other posts about this, I haven't seen them so I'll ask this: is this your first body on frame vehicle?

I notice this at lower speeds the most, the cutoff is about 40mph. My rear tires don't seem to be causing any one sided bouncing.
Road bumps such as potholes that have been freshly filled with asphalt mounds, as well as small dips around manholes. There's a manhole near my house, I'll take a picture and post it tonight. For the smaller road imperfections the stwering wheel feels more like it's providing feedback, with small jumps of about 10 degrees.
This is my first body on frame.

 

[sc470]

Okay. I had to go back and give your first post another look because this isn't adding up.

At what speeds are you noticing this? When this kickback happens, do your rear tires go over these same bumps/holes and give the sensation of the rig "bouncing" to one side? What kind of road bumps?

If you've made other posts about this, I haven't seen them so I'll ask this: is this your first body on frame vehicle?

This is the manhole I mentioned. You can't tell from the picture, but there is some unevenness in the pavement around it. My GX feels that when my front wheel goes over it and I get slight feedback in the steering wheel.

 

[OG Zuninja]

I had a feeling this was your first body on frame. What you're describing sounds pretty normal to me. Your alignment being as off as it was is concerning but it looks to be ironed out. The SAI still bothers me but like I said before, I'm not an expert.

As for your tire pressure, do a chalk test so you know you have the right pressure for your setup. Hope that helps.

 

[sc470]

I had a feeling this was your first body on frame. What you're describing sounds pretty normal to me. Your alignment being as off as it was is concerning but it looks to be ironed out. The SAI still bothers me but like I said before, I'm not an expert.

As for your tire pressure, do a chalk test so you know you have the right pressure for your setup. Hope that helps.

I'll take the truck tonan actual shop because I can keep diagnosing this myself till kingdom come. They'll take a look at the SAI angle and anything else noteworthy. Talking to some coworkers that drive Toyota trucks, it seems this is a pretty normal occurrence.

 

[use2bn83]

That’s a lot of caster, that could be causing a somewhat violent return to center after a bit of bump steer. Are your uppers adjustable? You may try taking a degree of caster out and seeing if that helps.

Your SAI could be the result of adjustable upper arms not being adjusted the same on both sides and compensated for with lower cams. Or a slightly bent knuckle or something.

 

[sc470]

That’s a lot of caster, that could be causing a somewhat violent return to center after a bit of bump steer. Are your uppers adjustable? You may try taking a degree of caster out and seeing if that helps.

Your SAI could be the result of adjustable upper arms not being adjusted the same on both sides and compensated for with lower cams. Or a slightly bent knuckle or something.

It's not the return to center issue, it's the fact that the steering wheel weers to the side on bumps, as in moves from its centered position. It exhibited similar behavior before the aftermarket UCAs. They are not adjustable, by the way, just have extra caster built in to compensate for caster lost after lifting.