Mark Francois

I don’t believe the splines on the yoke are worn at 140k miles but who knows. I did get down, watch, and listen but the noise is difficult to pin point. Plus my wife was doing the shifting while I was laying next to the running truck and she knows how much insurance I have on myself so yeah I was a little nervous lolol

I've got a 2003 Yukon 2wd with the 4.8l engine and after having my rear axle serviced a few months ago I developed a hollow sounding thunk from underneath the truck when shifting from drive to reverse and back. Sometimes it will do it when backing up my driveway and adding throttle but I cant rundown where it is coming from. They did replace the pinion seal during the service so my first thought was the rear u-joint but I looked and there is no slop in them... I am out of thoughts for now so any input you guys might have would be great. as always, thanks in advance.

Turned out to be the abs unit itself.

Well, changing out the front two abs wheel sensors didn't fix the issue. At first it seemed right but then it lot up again then it was off and then it was on again lol I didnt mind the work it took to swap those out but dang I’m tired of this intermittent problem garbage!

Well, the grounds were not the issue so I got off my lazy butt and tested the sensors themselves. What I found was that the passenger side sensor output was half the voltage (AC) of the drivers side. I belive that testing the sensor with a multimeter on AC while spining the tire is the proper way to check function. I know that the rate in which I spun each wheel was not exact betwen the two but it wasnt so much of a difference that the voltage should differ by half. What do you guys think? Something else I noticed while troubleshooting this issue is that when not in alarm, unplugging the drivers side sensor only illuminated the abs light but when unplugging the passenger side sensor tripped the abs and brake icons in the dash. Is this the intent to help mechanics differentiate between faulty sides or am I seeing something else and don’t realize it?

Cool deal! I’ll try what you suggested this weekend. Thanks.

Thanks guys, I'm guessing that you mean these two grounds attached to the body mount perch under the drivers footwell just behind the front wheelwell? If so, I'll clean them up and put some DI grease on them this weekend.

I've been getting an intermittent Service Brake System Message along with the ABS light and Parking Brake warning light on my 2003 GMC Yukon 2wd with the 4.8l motor. Sometimes it will be days or a week or two between getting the message or maybe one day to the next but they always clear up after I drive a little, stop and restart the truck,. Sometimes it is as quick as just driving just a couple hundred feet and restarting the truck or it may be when I reach my destination. I'm hoping that it is just an intermittent failure from one of the front ABS sensor but is there a way to check the sensors out with a multimeter to make certain that it is them or just a way to trouble shoot the system in general. It is kind of a tough one since it is an intermittent issue. Thanks in advance!