i was replacing the spider gears in rear diff all happy that the gears i bought as a hope work deal and they fit and worked woohoo...them my co-worker asked me how does the rear only abs know to work if there is know censors on front wheels? now its driving me crazy cause i dont know lol...anyone happen to know the answer

 

I don't think it matters it runs off the gear set, spiders will not affect the ABS. The sensor reads the large gear can't remember what that gear is called ring gear I think.

 

Should be a tone ring on the carrier in the rear diff. (goes between the carrier, and ring gear.) Sensor reads off that.

As for how the PCM knows if the rears are sliding or not..... on that, no idea. Not like it really has anything to compare it too... May it watches the rate of change in speed?

 

There is a magnetic sensor that reads the tone ring in the rear. When the wheels turn different rates, it picks it up and works the brakes. It works better than you might think.

 

That's correct it's not the ring gear it reads it reads the part attached to it.

I forgot that

 

PCM doesn't know anything about the spider gears, or individual wheel speeds.

 

The pcm just senses rate of decel. If the speed sensor in diff is un plugged abs won't work. I played with it on a hoist in my 03. It's all it can do without front sensors.

 

got it ..thanks o and if any one needs new spider gears for the 8.25 diff summit racing has them under # MGR-C8-25BIL.says they fit 8.25 and 8.375 they were 105.00 shipped.so far they fit and are working good in my dak

 

I always marvel when someone can set gears up properly. That is one thing I've never been able to do to my satisfaction. Replacing the pumpkin is easy but setting gear lash and such is beyond me. I was always extremely far sighted and never was any good at close up work.

 

I have a pair I use in my shop, bifocal safety glasses. They work OK, but I won't do bifocals again. From now on it's a pair for closeup work and another for not so closeup work.