What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[Doubeleive]

Will they really yield that much horsepower? I’ve been thinking about installing one but I’m not really trying to drop $200 on something from catchcans.com. Does anyone here have any experience with the cheap Chinese ones on Amazon? A lot of them have pretty good reviews.

 

[Hi-psi]

So three or so weeks ago I installed a McGaughy's 2/3-4 drop.

Since the install, I've had an issue of intermittent low speed ABS activation while turning sharply. If I'm on the brakes, the ABS pulses, if I'm not then just the traction control light flashes.

So, obviously a wheel or two is not reporting speed correctly making the system think either a wheel is locking up, or losing traction.

I was out of town for a couple of weeks with work, so in the last few days finally got a chance to circle back on this. I replaced all four wheel speed/abs sensors. No change. Exactly the same behavior. I'm at a bit of a loss now. On the drop spindles on the front, with how where the hub/wheel bearing is located, the sensor is a bit of a tight fit between the spindle and hub, but it's fully seated.

The front wheel bearings/hubs are fairly new (less than a year) Timken units. The only thing I can think of now is that when removing the sensors out of the wheel bearings/hubs while installing the drop spindles some trash or debris got down into one of them and maybe that's causing a funky reading/signal? When I put the new sensors on, I rotated the hubs 360* while looking down inside and they both looked clean.

I'm tempted to just throw a couple of new front wheel bearings/hubs on it and keep the current ones as backups, but I'm open to any other thoughts, ideas, or suggestions before I just throw parts at it.


I don't think any of the generic scan tools have the ability, but is there a scan tool out there that has the ability to log or read all four wheel speed sensors? That might assist me in targeting which corner is the culprit.

 

[CHOO CHOO]

So three or so weeks ago I installed a McGaughy's 2/3-4 drop.

Since the install, I've had an issue of intermittent low speed ABS activation while turning sharply. If I'm on the brakes, the ABS pulses, if I'm not then just the traction control light flashes.

So, obviously a wheel or two is not reporting speed correctly making the system think either a wheel is locking up, or losing traction.

I was out of town for a couple of weeks with work, so in the last few days finally got a chance to circle back on this. I replaced all four wheel speed/abs sensors. No change. Exactly the same behavior. I'm at a bit of a loss now. On the drop spindles on the front, with how where the hub/wheel bearing is located, the sensor is a bit of a tight fit between the spindle and hub, but it's fully seated.

The front wheel bearings/hubs are fairly new (less than a year) Timken units. The only thing I can think of now is that when removing the sensors out of the wheel bearings/hubs while installing the drop spindles some trash or debris got down into one of them and maybe that's causing a funky reading/signal? When I put the new sensors on, I rotated the hubs 360* while looking down inside and they both looked clean.

I'm tempted to just throw a couple of new front wheel bearings/hubs on it and keep the current ones as backups, but I'm open to any other thoughts, ideas, or suggestions before I just throw parts at it.


I don't think any of the generic scan tools have the ability, but is there a scan tool out there that has the ability to log or read all four wheel speed sensors? That might assist me in targeting which corner is the culprit.

Mines done the same since I had it installed 8 years ago. Never caused a problem and went away immediately. Wish I had a better answer, just wanted to give my experience.

 

[iamdub]

So three or so weeks ago I installed a McGaughy's 2/3-4 drop.

Since the install, I've had an issue of intermittent low speed ABS activation while turning sharply. If I'm on the brakes, the ABS pulses, if I'm not then just the traction control light flashes.

So, obviously a wheel or two is not reporting speed correctly making the system think either a wheel is locking up, or losing traction.

I was out of town for a couple of weeks with work, so in the last few days finally got a chance to circle back on this. I replaced all four wheel speed/abs sensors. No change. Exactly the same behavior. I'm at a bit of a loss now. On the drop spindles on the front, with how where the hub/wheel bearing is located, the sensor is a bit of a tight fit between the spindle and hub, but it's fully seated.

The front wheel bearings/hubs are fairly new (less than a year) Timken units. The only thing I can think of now is that when removing the sensors out of the wheel bearings/hubs while installing the drop spindles some trash or debris got down into one of them and maybe that's causing a funky reading/signal? When I put the new sensors on, I rotated the hubs 360* while looking down inside and they both looked clean.

I'm tempted to just throw a couple of new front wheel bearings/hubs on it and keep the current ones as backups, but I'm open to any other thoughts, ideas, or suggestions before I just throw parts at it.


I don't think any of the generic scan tools have the ability, but is there a scan tool out there that has the ability to log or read all four wheel speed sensors? That might assist me in targeting which corner is the culprit.

On the rear, trace the sensor wires up to the top of the frame and check that connector. It's common for this to get pulled loose when the rear is articulated beyond it's normal ROM, such as when dropping the rear to R&R the coil springs.

 

[Doubeleive]

So three or so weeks ago I installed a McGaughy's 2/3-4 drop.

Since the install, I've had an issue of intermittent low speed ABS activation while turning sharply. If I'm on the brakes, the ABS pulses, if I'm not then just the traction control light flashes.

So, obviously a wheel or two is not reporting speed correctly making the system think either a wheel is locking up, or losing traction.

I was out of town for a couple of weeks with work, so in the last few days finally got a chance to circle back on this. I replaced all four wheel speed/abs sensors. No change. Exactly the same behavior. I'm at a bit of a loss now. On the drop spindles on the front, with how where the hub/wheel bearing is located, the sensor is a bit of a tight fit between the spindle and hub, but it's fully seated.

The front wheel bearings/hubs are fairly new (less than a year) Timken units. The only thing I can think of now is that when removing the sensors out of the wheel bearings/hubs while installing the drop spindles some trash or debris got down into one of them and maybe that's causing a funky reading/signal? When I put the new sensors on, I rotated the hubs 360* while looking down inside and they both looked clean.

I'm tempted to just throw a couple of new front wheel bearings/hubs on it and keep the current ones as backups, but I'm open to any other thoughts, ideas, or suggestions before I just throw parts at it.


I don't think any of the generic scan tools have the ability, but is there a scan tool out there that has the ability to log or read all four wheel speed sensors? That might assist me in targeting which corner is the culprit.

TECH2 will tell which sensor/hub is going goofy, a standard scanner that does abs might tell you, but like chris said check the rear abs connectors they are dead center above the rear top shock bolt location

 

[Hi-psi]

I'm well aware of the fragile rear ABS sensor connectors, not the issue. One of the first things I tried with the original sensors. And since have replaced the rear sensors, again ensuring solid, seated connection.

I feel like it has something to do with the front.

@CHOO CHOO - So, you had the same/similar issue after installing drop spindles but at least for you it eventually just went away on it's on?

 

[CHOO CHOO]

I'm well aware of the fragile rear ABS sensor connectors, not the issue. One of the first things I tried with the original sensors. And since have replaced the rear sensors, again ensuring solid, seated connection.

I feel like it has something to do with the front.

@CHOO CHOO - So, you had the same/similar issue after installing drop spindles but at least for you it eventually just went away on it's on?

I still get the abs on a tight turn sometimes. More like if it's a tight turn on an uneven surface. It's weird, I've never really tried to pinpoint it, but the uneven or elevated ground while making a sharp turn usually makes it happen for me. Hope that makes sense.

Like turning into a driveway that has those dips for drainage right as you enter the driveway. My old driveway was on a steep incline, so when I would turn into it, that's when it would come on, then go away as soon as it straightened out.

 

[Tonyrodz]

.

 

[iamdub]

I still get the abs on a tight turn sometimes. More like if it's a tight turn on an uneven surface. It's weird, I've never really tried to pinpoint it, but the uneven or elevated ground while making a sharp turn usually makes it happen for me. Hope that makes sense.

Like turning into a driveway that has those dips for drainage right as you enter the driveway. My old driveway was on a steep incline, so when I would turn into it, that's when it would come on, then go away as soon as it straightened out.

I wonder if the McG spindles change the scrub radius and it causes the wheels to exceed the allowable difference. If so, I wonder if this can be mitigated by dialing in a little more (negative?) caster, or ensuring both sides are set equally. Is there any Ackerman built into the alignment specs on these things? Aftermarket spindles could throw that off. Although, I thought the big deal with McG's spindles is that they maintained the factory articulations.

 

[Hi-psi]

I wonder if the McG spindles change the scrub radius and it causes the wheels to exceed the allowable difference. If so, I wonder if this can be mitigated by dialing in a little more (negative?) caster, or ensuring both sides are set equally. Is there any Ackerman built into the alignment specs on these things? Aftermarket spindles could throw that off. Although, I thought the big deal with McG's spindles is that they maintained the factory articulations.

Interesting thought, but I don't really see how that could be happening. With the drop spindles, none of the suspension angles change really. Only the axle angle (if AWD/4WD). You're simply moving the wheel bearing/hub up 2". I had my alignment checked after installing them and it was still dead on.

The only thing I've read about the McGaughy's spindles is that you lose a little full lock turning radius, which can be easily remedied by grinding down a little material off the spindle.

Don't think that's related to what I'm experiencing though as the issue isn't happening when only at full lock.


I suppose my three potential courses of action right now are....

1. Try to get access to a Tech2 (or similar) scanner that can read/record the individual sensors data to target which corner is the culprit, then go from there.
2. Throw another set of wheel bearings/hubs on it and cross my fingers it wasn't wasted money.
3. Put the factory spindles back on, deal with the embarrassment of the "squatted" look for a few hours, drive around, see if the problem is gone.