Put a couple thousand KM on my Sub this week and while driving to work this am noticed the steering wheel was jerking. Almost like someone had their hand on it giving it a quick jerk and then back to centre. Put truck in 4Hi and drove for about a mile then disengaged it. By the time I got to work it had stopped. What's up?

loose steering linkage, bad steering dampener or bad CV joint.

Any noise during turns? in 4x4?

If you have any noise during turns, check the CV's. I had one making noise, then it got louder and started affecting steering. Could not tell that it has the CV, except it warmed up when driving in 4x4, compared to other CV's, or once it was out of the truck you could feel the bad spot.

I've had the steering dampener cause steering changes when it rusted out on my 83 gmc. It scared the F out of me:eek:!!

Also check the pitman and idler arms in the steering linkage, make sure they are tight and not worn out.

Is it jerking while going around a curve?

Is it jerking while going around a curve?
No while going straight at about 50mph. Front end is pretty tight. I checked it last week.

Been having the same issues on the K3500. Really noticed it this past weekend on a 1400 mile round trip. Almost feels like the wheels are "hopping" at times. Also noticed some above average wear on the inside edge of the front tires. Took it to the alignment shop.....Don't know if this is your problem, but the upper and lower control arm bushings need replaced. They wanted over $700.00 to do both uppers and lowers. Think I'll do them myself, and go back to them for the alignment afterwards:)

Odds are you may need an EVO sensor. This is for variable assist power steering, and is located near the bottom of the steering column. It is gray plastic with a wire harness coming out the top. Putting the truck in 4 wheel drive disables the variable assist. You can disconnect the sensor to confirm.

Odds are you may need an EVO sensor. This is for variable assist power steering, and is located near the bottom of the steering column. It is gray plastic with a wire harness coming out the top. Putting the truck in 4 wheel drive disables the variable assist. You can disconnect the sensor to confirm.
Thanks for the info. I will try disconnecting next time it happens instead of using 4x4. How does the variable steering work?

You can also unplug the assist harness going to the steering pump to disable it. I have experienced it but mostly in turns. Honestly, it should be a friggin recall because it is seriously not safe when you pushing it in a corner and then it just turns in all of a sudden. The problem is not in any lack of steering but a boost in assist pressure allowing you to over steer.

You instinctively learn how much force it takes to turn the steering wheel while rolling but when that pressure boosts, it feels like a sudden jerk. I got so pissed with a shop truck one day, I called a friend at a dealership to find the wiring associated with it, pulled over in a parking lot, and pulled that sucker.

Wasn't EVO only used in the '97 and '98 model years?


Andy

You instinctively learn how much force it takes to turn the steering wheel while rolling but when that pressure boosts, it feels like a sudden jerk.

My 97 Tahoe (gasser) did this for a while until fixed. Chevy mechanics at the dealer says its a common problem seen there for those years (including sagging doors and broken door latches!)

Thanks for the info. I will try disconnecting next time it happens instead of using 4x4. How does the variable steering work?

There is a control in the system that regulates the flow depending on steering input. (you)

The EVO sensor reads the movement of the steering wheel (amount and speed)

When you are driving down the road the variable assist is reducing flow to give you a firmer feel.

When doing a considerable amount of turning (like parking lot manuevers) the flow is increased to assist steering.

When this sensor goes bad, your slight correction in steering (road crown or side wind) makes this sensor spike, sending full flow through your power steering system. This gives you the jerking sensation.

I don't believe this system was used in the Silverado/Sierra new body style pickups in 99, but it was in the old steel 3/4 and 1 tons, as well as the Tahoe, Yukon, Suburban until their body change.

Hope this helps you,

Mike

I've had this symptom with a GM p/s pump that was going bad. Did it worse cold. New pump and problems were gone.

If you can get it to grab while sitting still have someone turn the steering wheel back and forht while you watch the pulley. If the pulley is stalling it 'might' be the pump.

I don't know how to diagnose it for sure, though, I just swapped mine and it solved it. Mine was a plain-jane Saginaw pump to box system, not a progressive resistance or hydroboost setup - so there weren't many options of what the problem might be...

Chaser

It seems to be worse when going from say 10kmh to 110kmh pushing the accel pedal hard. Then when you reach 100-110kmh it starts jerking. Only sometimes...sounds like what you are suggesting is possible casuse. I looked under the steering column for a grey harness as described but could not find it...It was raining like hell and cars were speeding past which did not help...can I unplug it at the PS pump?

Yes, you can disconnect it at the pump. Under the dash, near the two bolt mounting flange for the column, there is a gray disc shaped sensor. At the top of the sensor is where the wires come out. A few inches down the harness is the plug. I have attached a picture of the replacement part. The factory part is usually gray.

Yes, you can disconnect it at the pump. Under the dash, near the two bolt mounting flange for the column, there is a gray disc shaped sensor. At the top of the sensor is where the wires come out. A few inches down the harness is the plug. I have attached a picture of the replacement part. The factory part is usually gray.
Thanks for the info...i will try on my way home tonite. Dan

I unplugged connection to the EVO system at the PS pump. Now steering wheel jerks at lower speeds... and more violently.

I assume because full pressure to the steering box means a harder jerk?

Any ideas? Replace steering box? I think I will try some Lucas PS additive first. I will put some in tonite and drive tomorrow. I think problem is worse when truck is cold...?

I unplugged connection to the EVO system at the PS pump. Now steering wheel jerks at lower speeds... and more violently.

I assume because full pressure to the steering box means a harder jerk?

Any ideas? Replace steering box? I think I will try some Lucas PS additive first. I will put some in tonite and drive tomorrow. I think problem is worse when truck is cold...?

Let's back up a little bit. Is it 1 jerk in the same direction every time, or is it more side to side and more than one jerk?

Jerks to the right. Numerous times on a stretch of road...then stops.
With EVO unplugged it seemed more violent of a jerk but same direction.
Does it for a couple of miles after about 6-8 minutes of driving. Dan

Jerking definitely goes away after driving it for 10 miles or so. It feels like someone is grabbing the wheel and giving it a slight jerk to the right every 5-10 seconds.

Ive run into this before but my case is that its time for a brake job. When you apply the brakes you would get a wobble if you slammed on the brakes its not that bad. I ended up doing all new rotors, pads, alignment and a few misc front end parts.

Low and behold Ive been traveling across the nation and it just started doing this when I got home again. I remember this used to be called the Death Wobble in the Jeep community. It can get pretty violent.

Ive run into this before but my case is that its time for a brake job. When you apply the brakes you would get a wobble if you slammed on the brakes its not that bad. I ended up doing all new rotors, pads, alignment and a few misc front end parts.

Low and behold Ive been traveling across the nation and it just started doing this when I got home again. I remember this used to be called the Death Wobble in the Jeep community. It can get pretty violent.

I do not think it is brake related. Happens when driving down straight road.

mine did it across train tracks etc. I replaced the steering damper after rebuilding complete front end and alignment. my problem solved.

Jerking definitely goes away after driving it for 10 miles or so. It feels like someone is grabbing the wheel and giving it a slight jerk to the right every 5-10 seconds.

This screams EVO sensor, but if you disconnected the solenoid on the power steering pump pressure line, it would have put the p/s system to full flow, and the problem would have stopped.

Now, I need to trouble you with more questions;

How many miles on the Suburban?

When starting the truck, look closely at the steering wheel, does it move or jump in one direction?

Next, jack up front end, then turn steering from lock to lock with engine off. Do you feel any binding?

Let me know, and I'll see what we can figure out.

Mike

How much coffee do you drink? :D

This screams EVO sensor, but if you disconnected the solenoid on the power steering pump pressure line, it would have put the p/s system to full flow, and the problem would have stopped.

Now, I need to trouble you with more questions;

How many miles on the Suburban?

When starting the truck, look closely at the steering wheel, does it move or jump in one direction?

Next, jack up front end, then turn steering from lock to lock with engine off. Do you feel any binding?

Let me know, and I'll see what we can figure out.

Mike

Ok Mike
211,000km, approx 132,000miles

When truck starts steering wheel does not move.

Jacked up front end and turned wheel lock to lock...no dragging or tightness(wheel is hard to turn and PS pump puked out some fluid but that is normal IMO)

I Also started truck on jack and steering wheel does not move. Thanks Dan

Just throwing my idea out there for ya Dan...What condition are your tires in? Maybe switch fronts to the back. I had some weird wobbly steering problems a few years ago, and found one of my front tires to have separated cords. The tire had really good tread, but for some reason, a small bulge happened to form on the inside of the tire when I removed it. First for me.

Just an idea though...

Good luck with everything man.

Just throwing my idea out there for ya Dan...What condition are your tires in? Maybe switch fronts to the back. I had some weird wobbly steering problems a few years ago, and found one of my front tires to have separated cords. The tire had really good tread, but for some reason, a small bulge happened to form on the inside of the tire when I removed it. First for me.

Just an idea though...

Good luck with everything man.

Tires are 80%+ Just rotated tonite...found a leaky rear axle seal on Drivers side. Also found that the brake drums can be removed without pulling the axles. :)
This explains why truck pulls to the left with you stab the brakes on hard...but not the jerking.

What do we have EVO system. I pulled this link if it is any help http://www.asashop.org/autoinc/april2005/techtips.htm

If not it sounds like you have some binding/dragging in brakes, bearings, or steering linkage.

Do the wheels get to hot to touch on the spindles/drums from dragging bearings/brakes? Someone suggested the upper bushings also so with the front end off the ground do you get any movement in the wheel by pulling the tire/wheel in all directions with hands on tire top/bottom, side to side, spin check? Looking for looseness in bearings, balljoints, and bushings. Making an alignment check.

Ignition key turned to unlock steering wheel and checking for turning of steering gearbox/pump at tire wheel with hands. If jack stands under lower control arms and 2-3inches clearence under tire use a big bar to move tire up while watching ball joints to check for loose movement in balljoints.

this is great information ... someone really needs to get a good sticky going at the top on this forum with all the goodies

Ok Mike
211,000km, approx 132,000miles

When truck starts steering wheel does not move.

Jacked up front end and turned wheel lock to lock...no dragging or tightness(wheel is hard to turn and PS pump puked out some fluid but that is normal IMO)

I Also started truck on jack and steering wheel does not move. Thanks Dan

Well if you have none of these other symptoms, I would suspect either a sticky check valve in the power steering pump, or a sticking valve in the gearbox.

I would try to flush the system out and refill with power steering fluid (not ATF)

Keep me informed,

Mike

Well if you have none of these other symptoms, I would suspect either a sticky check valve in the power steering pump, or a sticking valve in the gearbox.

I would try to flush the system out and refill with power steering fluid (not ATF)

Keep me informed,

Mike
I was thinking the same...I removed about 12oz of fluid and installed Lucas PS conditioner, seems to be a little better today. Funny part is I have to drive for 8-10 minutes before it does it. If the Lucas doesn't work I will try some Seafoam...

Well after all the replies I narrowed it down to the steering box or pump having a sticky valve or tight spot. As I am far to cheap to replace the steering box I tried some Lucas power steering additive with a money back guaranttee...I should have my money back in a couple of weeks... Then I drained the Lucas out and refilled the pump with 12 ounces of Seafoam for auto transmissions and hydraulic components. Ran the truck to work and back, about 45 mins driving total and drained the seafoam and replaced with PS fluid. Ran another day and drained and re-filled it again as I had 1/2 quart or PS fluid left. Jerking has stopped. Just got home from Tacoma WA, about a 600km round trip and no jerking... Thanks for all the suggestions.

Well after all the replies I narrowed it down to the steering box or pump having a sticky valve or tight spot. As I am far to cheap to replace the steering box I tried some Lucas power steering additive with a money back guaranttee...I should have my money back in a couple of weeks... Then I drained the Lucas out and refilled the pump with 12 ounces of Seafoam for auto transmissions and hydraulic components. Ran the truck to work and back, about 45 mins driving total and drained the seafoam and replaced with PS fluid. Ran another day and drained and re-filled it again as I had 1/2 quart or PS fluid left. Jerking has stopped. Just got home from Tacoma WA, about a 600km round trip and no jerking... Thanks for all the suggestions.

You get a heads up for thinking of flushing & changing the fluid. Question; what did the fluid look like prior to the Lucas journey & what did the fluid look like when you drained it prior to the Seafoam. Was there a distinct color &/or smell?

You get a heads up for thinking of flushing & changing the fluid. Question; what did the fluid look like prior to the Lucas journey & what did the fluid look like when you drained it prior to the Seafoam. Was there a distinct color &/or smell?
After Lucas it looked like ps fluid.
After seafoam it smelled bad and had a slight burnt odor.
After 2nd PS fill it looked like PS fluid again. Dan