I've got a 2003 F150 SuperCrew with a 9.75" rear end with 3.73 gears. I've been battling a clicking noise when I slow down with no break pressure and it happens around 15-25mph. It doesn't do it all the time but when it does it its a consistent click, click, click, click. I've changed the rear pads. The ones had a little up and down play. This didn't solve it. Next was the parking brake. Its not the problem its not even hooked up or there for the matter. Ujoints are tight. There is a little up and down play where the driveshaft goes in the tailshaft of the transfer case. There is no leaking oil or anything. I just changed both rear wheel bearings last night thinking it was those. Took it down the road and still had some clicking. I noticed when I had it it apart and the diff cover off there was a little play up and down with the spider gears are those supposed to be tight? They moved maybe and 1/8 of an inch up and down on the lock pin. Also when I was digging around in the bottom of the rear end housing I found 3 round metal pieces. Not a clue of what they could be but some of them had numbers on them. If anyone has any ideas of what it could be I'd appreciate the help! Thanks

 

Those are parts of the spacers that belong behind the spider gears. 1/8 inch play is too
much, 1/16 is about max. Sounds to me like you should be working towards rebuilding or
replacing that rear end before it turns to schrapnel.

 

I am experiencing a similar problem (2002 F150 supercrew FX4 4x4 5.4L axle=H9 9.75 3.55 limited slip). I noticed during a differential lube oil change that the pin has some play in it. When I accelerate from a dead stop I hear a distinct loud click noise from the rear end. I only hear it one time as I accelerate from a stop. If I creep away from a stop and not press the gas until I'm moving I won't hear the click, same as when I'm in reverse (backing up). Oil was free from metal shavings just needed to be change. I added a friction modifier as well to the new oil. Let me know if you get to the bottom of your problem...

 

Well I think I got it figured out. From what Rebel posted and what two ford dealers say is that it's the shim washers behind the spider gears and looking at the diagram it makes sense. 135$ for the kit. Comes with all 4 spider gears and shim washers. I'm not sure what to do with it yet. Do I put a new carrier in for 300 from summit or do the repair and hope once I get itall apart there's nothing else wrong. What's your guys opinions?

 

Replace the shims and all should be fine.