First off, I'am new to this forum, Hello. I have a '02 350 w/ 63K on it. Now I've noticed a growling noise from the rear diff. I've pulled the cover and droped the drive shaft. The pinion has some rotation play to the ring but nothing I'd call bad. And no side to side or in/out play. The pinion to ring gear teeth look as though the mesh is correct (I checked this by site only with grease on the ring). The axels/bearings have no play. But still as I spin the wheels the noise get louder. Any thoughts??? I stumped.

 

sounds like the spider gears may need attention. Is it single wheel drive or posi?
When you spin just one wheel the spiders come into action and can exhibit a lot of grumbling (growling noise) ecspecially if you do it alot.
JIM

 

It's a posi, so when i spin one wheel the spider gears are not inmotion? corect?

 

Maybe, Are you spinning one wheel or both? If it's both, it sound like your posi is taking a dump.

 

sometimes just changing the fluid solves the problem. Be sure to use a friction modifier for posi units.

 

When I turn one wheel (either side) they both turn in the same direction. With the rear jacked up and fluid in, I've run the truck in gear and It makes the growling noise. Just an after thought, but does that sythenic gear oil from Ford break down?

 

My limited "locked" up at about 41,000. It was so loud I thought I giving people headaches that were going the other direction!! Turned up the radio and just kept driving it, at 145,000 it stopped making all that noise!! No differance in traction that I can tell!! Now, when I turn left or right I feel a pulsing sensation!! It feels like 3 marbles under the inboard wheel then nothing then 3 marbles again!! But only when under power. Coasting will not do it!!

 

should be covered under warranty right?