ABS/Hub Binding Issue

[Laramie321]

The ABS on my 2017 Ram 1500 w/ 4wd Auto activates at 30mph or less with light/moderate braking. The ABS light is NOT on, and I am not seeing any codes. This is happening on and off dry pavement. Happens when in 2wd or 4wd. When the ABS kicks on, it does not stay on constantly, it seems to surge on/off, and the surge changes with wheel speed.

Investigating this further, I have noticed the front driver hub is doing something odd (at least I think it's odd). With the front wheels in the air, wheels off, truck in 2wd, the driver front hub will rotate freely and then hit a "wall" of resistance every ~120° of rotation. To get through this resistance I have to take a prybar to the hub and rotate through. When there is resistance, the front drive shaft (between diff/transfer case) will rotate slightly, once I get past the resistance, the front drive shaft stays stationary (again, this is happening in 2wd). On the passenger side, the hub rotates freely 360°, no rotation of the front drive shaft.

In 4wd lock, the front drive shaft rotates when I rotate either the driver or passenger hub. There is still a noticeable "wall" of resistance on the driver side when in 4wd lock. 4wd does work, both wheels get power.

I’m wondering if the surging on/off of the ABS is tied to hub resistance at 120° of rotation on the drivers side front hub. What is going on here? Is this a symptom of a bad hub assembly? Do I have something more serious going on? Any help/suggestions are greatly appreciated.

 

[04fxdwgi]

Take the brake caliper off the rotor on the drivers side. Have seen warped rotors do that. A bad rotor will also feel like the ABS is kicking in and out
If it still does it with caliper off, I would be really looking real hard at the drive / stub shaft on that side..

 

[Laramie321]

It still does it with the caliper off and even the rotor taken off. When this issue started a couple weeks ago, I assumed it was worn rotors and pads and they were about due for replacement, so I have all new rotors and pads, issue still persists.

Just to clarify, you're saying check the CV axle and corresponding inner cv axle (short stub shaft)?

 

[Mojo88]

Could be any number of things, ABS sensor, sticking caliper, bad CV axle (this is my primary suspect), or other. But I agree with @04fxdwgi , I think Step 1 is to take brake caliper off and see if it still does it, or perhaps watch this 90-second video and then perform the simple CV axle tests:

How to Diagnose a Bad CV Axle

Shop for New Auto Parts at 1AAuto.com https://1aau.to/c-84-XIn the video, 1A Auto shows how to diagnose or check to see if you need to replace your axle or C...

www.youtube.com

 

[04fxdwgi]

It still does it with the caliper off and even the rotor taken off. When this issue started a couple weeks ago, I assumed it was worn rotors and pads and they were about due for replacement, so I have all new rotors and pads, issue still persists.

Just to clarify, you're saying check the CV axle and corresponding inner cv axle (short stub shaft)?

Yes, the CV joints, stub axle and such