f-150 differential

Something in my rear end is clanking when I accelerate hard from a stop, so I looked at the differential and noticed an (electric?, def. not pnuematic) line running into the top. I've never worked on a differential, so I have no idea what it is. Can anybody tell me what it does? It's not a limited slip diff. by the way. Oh, and if you have any ideas on the clanking noise that would be helpful too.

It is either your U-Joints in the drive line or the ring and pinon gears have lot of wear between them.

What is the year and mileage of your truck?

the cable is probably for a speed sensor. it measures rpm, and with tyre rolling diameter tells you the speed.

The harness is going to the rear wheel ABS sensor.

then it would run along the axle shafts and to the hubs and brakes.

if it goes into the top of the diff it's probably a speed sensor. i know that Dodoge uses speed sensors fitted to the top of the diff, i'd image that it's a common place for them.

The vehicle speed sensor is located in the tranny on these. The single rear ABS isn't as effective dual sensors, but it works.

The sensor on top of the diff. is in fact the rear ABS sensor.

I've changed quite a few of them.

It's a '93 f-150 and I'll have to check the mileage. If it the ABS sensor, then why do I also have lines running along the axles? They merge into another line at the same place where the axle tube vent comes out. I would assume that is the ABS.

are they brake lines?

Actually yes. When you mentioned the sensor lines running along the axle I thought maybe thats what they were instead of brake lines. But I looked again and they are definately brake lines. My bad. And torch, its 133,000 miles.