03 Suburban LT Steering Issues, Wandering and Wobbly and Loose

[houstontaylor]

I would say you need new shocks if they are the originals. Worn out shocks can bounce you all over the road. On my 2003 Chevy Tahoe with more miles than yours I've replaced the shocks twice since the originals.

 

[Fless]

if its saying service 4wd, you got codes. normal scanner wont pick these codes up. need a abs scanner. even if the abs and brake lights are not lit up, you likely have a code (or 5 or 6) stored.

^^ THIS. A scanner that will read the 4wd codes will also show live data; in addition to the codes you can view live data and compare the commanded mode to the actual mode (2hi vs AUTO, for example). With the description you gave I would suspect the transfer case encoder motor to need a new internal range position sensor, or a new encoder motor. But the codes and live data would confirm.

Range position sensor:

 

[Meathead16]

Have you done anything to the rear? It's surprising how much the rear track bar and control srms can affect the control and stability and general feel of the ride.

How are your torsion bar mounts?

I have the same wheel hop/skip/bop on near full lock turns. I figured it was an alignment issue. Mine does leaves black tire marks everywhere it goes too. maybe the alignment needs checked again.. Firestone is a sketchy place to go. Never had anything but problems with them.. last straw was when they stripped the lug nuts on my moms car and the tire almost came off while driving. Never went to the same store twice so I can't help but think it's a top down compqny culture type issue.

 

[GMT800Man90]

^^ THIS. A scanner that will read the 4wd codes will also show live data; in addition to the codes you can view live data and compare the commanded mode to the actual mode (2hi vs AUTO, for example). With the description you gave I would suspect the transfer case encoder motor to need a new internal range position sensor, or a new encoder motor. But the codes and live data would confirm.

Range position sensor:
View attachment 446651

I just looked at everything on my scanner. Live data, actuation tests. There were no codes. Watching live data while switching through all the modes and everything looks great. Goes into each mode just fine. And out just fine.

 

[Fless]

I just looked at everything on my scanner. Live data, actuation tests. There were no codes. Watching live data while switching through all the modes and everything looks great. Goes into each mode just fine. And out just fine.

Well, I can assure you when the Service 4wd message is on, there will be at least one code. My eureka moment was when mine was switched into 4hi, in a few seconds the scanner would indicate the AUTO mode. The dash switch still indicated 4hi but it wasn't right.

 

[GMT800Man90]

Well, I can assure you when the Service 4wd message is on, there will be at least one code. My eureka moment was when mine was switched into 4hi, in a few seconds the scanner would indicate the AUTO mode. The dash switch still indicated 4hi but it wasn't right.

Yeah that's what I thought. But there were zero codes. Only one I've had was an evap code that comes on because my filler neck has a hole in it and leaks fuel if you fill it fast.

My scanner isn't one of the crazy expensive ones, but was still a $600 scanner and I can read and see all codes all modules and do all the bi directional tests and stuff. Everything looked great. Everything was switching fine. Never threw a code even when the service 4wd came on.

 

[Fless]

Again, if the Service 4wd message shows up on the DIC, there's a code at that time. The code triggers the message. You may need to verify that your scanner can read those codes, including Pending and History codes for the 4wd system.

 

[GMT800Man90]

Again, if the Service 4wd message shows up on the DIC, there's a code at that time. The code triggers the message. You may need to verify that your scanner can read those codes, including Pending and History codes for the 4wd system.

And I've done that. My scanner can do pretty much everything. It's not a cheap one. There are zero codes. Trust me. It'll throw service 4wd but the truck will drive just fine. Live data shows everything switching like it should, goes in and out of the different modes just fine. I pulled the grounds off, cleaned them and put new bolts on them and fluid filmed them since i live in Ohio. It didn't change anything that I've noticed. But no, in 2wd the truck is not stuck in 4wd. There are zero codes. None pending. None history. None current.

 

[Tonyrodz]

And I've done that. My scanner can do pretty much everything. It's not a cheap one. There are zero codes. Trust me. It'll throw service 4wd but the truck will drive just fine. Live data shows everything switching like it should, goes in and out of the different modes just fine. I pulled the grounds off, cleaned them and put new bolts on them and fluid filmed them since i live in Ohio. It didn't change anything that I've noticed. But no, in 2wd the truck is not stuck in 4wd. There are zero codes. None pending. None history. None current.

Maybe start fresh and disconnect the battery for awhile, also touch both battery terminal connections--the vehicle harness connections--this should clear out any codes. Then reconnect and take it for a ride, going in and out of 4wd. See what happens.