LML ABS Causing Strange Bump at Stop Lights

snowman22

Member
Jan 30, 2018
297
1
18
SoCal
I'm over it, time to throw some parts at it. Since it doesn't pull at all like my last truck did when it lost a front sensor I just ordered two rear sensors. If I'm going to spend the time pulling it apart, the $60 is worth just changing both sensors to see if it helps.
 

snowman22

Member
Jan 30, 2018
297
1
18
SoCal
I don't want to get too excited just yet, but after putting in two new rear wheel speed sensors the issue seems to be gone. It's only been a few days, but so far so good.

The old ones were covered in crap and honestly I need to take the hub apart and clean the reluctor wheel because it didn't look great. It looks like the wheel was submerged in some serious muddy water at some point.
 

Woodster

Computer Nerd
Aug 28, 2009
176
0
16
Utah
I don't want to get too excited just yet, but after putting in two new rear wheel speed sensors the issue seems to be gone. It's only been a few days, but so far so good.

The old ones were covered in crap and honestly I need to take the hub apart and clean the reluctor wheel because it didn't look great. It looks like the wheel was submerged in some serious muddy water at some point.

Good to hear. I'm not convinced that our issues are the same but I was in a similar situation and just started throwing parts at it. I was initially only going to do hubs & sensors but after tearing her all apart I'm doing axles, tie-rods, brakes, rotors, and ball joints. If none of that works I'll put her up for sale. :eek:
 

Woodster

Computer Nerd
Aug 28, 2009
176
0
16
Utah
Success here as well. It appears the speed sensors were causing my issues. She's downshifting perfectly now.
 

snowman22

Member
Jan 30, 2018
297
1
18
SoCal
This is old, but represents how long this has been an issue of mine and hopefully will help someone somewhere.

After replacing the rear wheel speed sensors my problem became much more intermittent until recently. I had always been under the impression all the other speed sensors were internal to the trans or transfer case so I never thought to inspect/clean them because both of those are beyond my comfort level of disassembly.

Long story short, I pulled and cleaned the VSS sensor on the top of the transfers case after my bump issue returned with avnengouns. It wasn't particularly dirty, just a fine layer of metallic material, but not the porcupine I thought I would find if it was causing an issue. After my disappointment I cleaned the sensor and housing thoroughly and reinstalled. It's been two weeks and it hasn't had the "bump" at a stop since and I couldn't go a day or two before.

I still don't know if it was and ABS freak out causing loss of brake pressure and then reapplying or if it was the trans going into "neutral" and then reapplying the clutch packs for 1st again, but it's gone for now. I imagine it was actually causing something in the trans just by how it felt, but it's really hard to say.

Moral of the story, I should have listened to James in the first place and looked at the transfer case.