Start with a scanner and live data on all four wheel sensors, see any unusual wear patterns on the rotors?

 

I don’t have an ABS scanner. No unusual rotor wear.

 

Sounds like you are getting a ABS style braking stop upon startup...meaning the ABS system thinks you are locked up and is pulsing the brakes for you, until you do this a couple times and the system sees a fault and turns on the ABS light. When the ABS light is on, the ABS system does NOT work. When you shut off the Jeep, the ABS system resets and clears its own codes. This is why the process starts all over again when you first start out driving. There is a problem with one of those new axles, or the sensors at the front wheels.(maybe damaged when the repair happened). Best thing to do is find a shop that can pull the ABS codes for you, but dont shut it off until they get plugged in, or they will have to drive it first.

 

It’s my understanding the ABS sensor reads the large gear on the axle shaft, is that correct? Would the type or quality of metal on that gear be a cause?
I did the axle change myself and was careful with the ABS cable. I don’t think I damaged the cable or sensor.

 

I’ve been having the same issue at the left rear. I replaced the axle a while back and that’s when the issue started. Replaced the abs sensor and still have issues. I’m not sure how a tone ring can be bad but you’ve definitely found out that it’s the cause. Wrong tooth count maybe?

If you look back at my post #5, I suspected the metal quality was the problem. The tone ring metal on the Detroit Axle shafts seemed like a poorer quality than the OEM ring. I stuck magnets to both and the magnet did not stick as strongly to the Detroit Axle ring as it did to the OEM ring. So I suspect the ABS sensor was unable to read the DA metal properly. The size and number of the grooves were the same in both.

 

Yes, there is a tone ring inside of the back of the wheel bearing, with a sensor off to the side. Are they lined up on both sides?(sensor with the tone ring). There are two different types of axles for these Jeeps, yours should be the more rare Quadradrive version. Are you sure they are correct? Did this Jeep have ABS issues before you did the axles? Maybe the light was on before? I noticed you said you had no ABS issues before, but if the light was on already, the ABS system would be disabled...

 

No ABS issues before, the warning light was never on before the axle shaft replacement. And the shafts are the correct length, I compared them to the stock shafts.

 

My 99 has tone rings on the front axles (I know because they were clogged with dirt and I had to clean them) , and should have them on every axle.
There are also ABS sensors on each wheel too.

Might it be possible Detroit axle did not provide tone rings and you have to use the old one?
That would explain the ABS starting over each time.... it's looking for the tone ring.

 

Something's up with those axles...hate to say it, but i think they need to come back out. Sad thing though, if your like me, the cores already went back and you wont be able to compare...If it isnt the axles, then it has to be one of the sensors got damaged in the exchange....If you could get those ABS codes pulled, maybe you wont have to pull both sides?

 

I put the original drivers side axle shaft back in. This side did not have a torn boot and the joint still seems solid - the passenger side joint was very loose and sloppy. But it did not resolve the ABS issue.
New Detroit Axle shaft on top, original on bottom. The pic angle makes it look like the older shaft is slightly longer but it's not, I measured them.
But the new shaft has a wider boot that got jammed against the axle tube and is already torn.
I'll see if I can get the ABS codes. And try replacing the ABS sensors.

 

Man, that sucks.....Another knock on Detroit axle parts....

 

Update: It appears the ABS ring from Detroit Axle was the problem. I pulled the passenger side axle shaft out and swapped the rings with the OEM ring. ABS light went out after driving it for about a minute. No more pulsating brake that I described in the OP and the ABS light has not come back on after several restarts.

 

I’ve been having the same issue at the left rear. I replaced the axle a while back and that’s when the issue started. Replaced the abs sensor and still have issues. I’m not sure how a tone ring can be bad but you’ve definitely found out that it’s the cause. Wrong tooth count maybe?