Wheel speed sensor?

Refer to diagram. If you encounter any abnormal grinding noises, the cause could be from the diffrential rather than the wheel speed sensors.

It sounds like the ABS module is going out here is a video to help you change it out.

https://youtu.be/lUotkKXG9dY

Disk or drum they should be similar in location. Check the rear of brake at backing plate to see if you can find the sensors.

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

Cheers

Hello,

In the diagrams down below I have included a diagram showing the locations of the Wheel Speed Sensors for your vehicle. They are located on the front wheels and not on the rear wheels as they will be traveling as fast as the rear wheels, so there is no need for them on the rear wheels. I hope this helps.

Thanks,
Alex
2CarPros

This is a very common problem that only applies to GM trucks. It's caused by rust build-up under one of the front ABS wheel speed sensors.

To generate a signal voltage, you need three things; a coil of wire, a magnet, and most importantly, movement between them. In this case, the wheel speed sensor is a coil of wire wrapped around a magnet, then the movement is actually the magnet's magnetic field being disturbed by the passing teeth on the tone ring. GM puts that tone ring inside their wheel bearing assemblies, but the sensor sits outside where water can get under its mounting pad, causing rust to form and build up. As it does, it pushes the sensor away from the tone ring.

These sensors develop real wimpy signals to start with, then they become even weaker when the air gap increases. Next, since movement is a factor in signal strength, the signals become even weaker as wheel speed slows down. By the time you get down to around 10 mph, the signal becomes too weak to be analyzed by the computer. It thinks that wheel has locked up, so it activates the various valves to try to get that wheel rotating again. That's called "false activation". It's the operation of those valves you're feeling.

The fix is usually to remove the sensor to clean off any rust under it. Many people replace the entire wheel bearing assembly, but most of the time that is not necessary. The red arrow is pointing to the area where the rust forms.

To the truck? No. To your nerves? Maybe. This is more of an irritation. The ABS system will still do its job in an emergency.

Check the ABS sensor lead (wire with magnetic pick-up unit) that goes into the top of your wheel bearing. (The toothed ring for the ABS is inside the wheel bearing). If the sensor is not reading the ring, it will tell the ABS unit that a wheel is slipping (when it is not), causing the ABS to activate just before you come to a stop. I had the same issue with my 2000, the wheel bearing was fine, there just was an issue where the bearing housing where the ABS sensor bolted to it had rust underneath the sensor where it bolts to the bearing housing. Just a mm of rust threw the sensor out of range making the ABS system think that the wheel was locking up. (Common problem where the city uses salt on roads). I thought I had to replace a wheel bearing ($$$$$) but just carefully pulled the sensor out, cleaned the corrosion off the housing and re-inserted the sensor. No more problems.

IS it a crow hop kind of feel?
Are you in 4wd at that time?

IF the brakes are false abs-ing, then clean thecorrosion build up under the front wheel speed sensors, clean the mounting pad and coat sensors with silicone grease.

IS the abs light coming on?

The sensor goes into the hub. Replacement ones come with the sensor becasue they don't come out in 1 piece too often.

Sorry, went down the wrong path on that.

Big aluminum driveshaft? They resonate noise pretty good.

Is the thumping /clunking noise in the rear axle while driving down the road, more noticeable it more on the one to two upshift? IF so, try greasing the splines on the end of the rear driveshaft that fits into the transfer case.

IF this is not the case either, then next I would mark the tires at the bottom with a crayon. Drive it for 10 wheel rotations. All of the marks should stilll be at the bottom. IF not then there is a circumference problem that may have caused damage.

IF I'm still in left field on this, post a fresh new question, so it flags as not being answered.