Hi all, I'm new here and proud owner of an 01 F-150 5.4 4wd. Now on to my question.. I recently took my truck in for a check up for rear end shuddering the mechanic came back saying I need to replace the rear end. Now as far as I can tell this is something I can do on my own. The problem comes in identifying the rear end assembly the door code is h9 and talking to the dealer the other code is 919f. Is this all I needed to get a suitable rear end from a salvage yard?
Again anyone who replies thank you a thousand times been scratching my head over this for a bit

 

I'm betting you do not need a rear end. Shudder can be caused by chattering limited slip clutches.

Change the rear end lube. Use 75W140 synthetic, any brand, and add a 4 oz bottle of Ford XL-3 friction modifier from the dealer. If the shudder doesn't stop in 2 weeks, add another bottle of XL-3.

 

Unfortunately I've tried that minus the friction modifier I do know it was full of metal shavings when it went into the shop. I'll try the friction modifier though. I'm just hoping there wasn't too much damage done as when I took the truck in they said it was almost empty ( recently purchased the truck). Thanks

 

Just an update I've got the friction modifier on the way. Hoping for the easy fix I'll hopefully update with good news in a week or so thanks for the advice!

 

I think the 919f identifies the axle diameter/axle bearing size. Some of them evidently came with larger axles and bearings than others. I found this out when I ordered a new axle and bearing for my 2002. Mine takes the smaller bearing/axle.

 

Ok first off thank you glc, you saved me a few hundred bucks and a day of cussing. The friction modifier worked perfectly it's like magic in a bottle stinky Magic but it's great. Now while I was putting that in I notice fluid on my rear drum it's not brake fluid so I'm thinking that's where all the diff oil has been going, well on to the next project

 

Yep, we used to call that stuff "skunk fluid".

Axle seals aren't that hard to change, but you do have to pull the diff cover to release the axle so you can pull it out. If you do this job, it wouldn't hurt to do both sides and replace the bearings while you are at it. This is where what Roadie says is important. You have a 9.75" axle, but some of them used the same shafts as the 8.8" axle.

 

To remove the axles, you have to remove the C-clips on the end. And to do this, you have to push the axle in towards the differential. It's an easy job, just messy. If you change the bearings, you might need a puller to get them out because they are a press fit in the axle housing. if the bearing rollers are pitted, you will need new bearings and axles since the axle is the bearing surface.

 

Ok thanks we'll see how it goes sounds like a good 12 pack job

 

So it wasn't this bad before but just took a picture to see if I'm following the right trail what do you think?

 

Definite axle seal issue, and I wouldn't be surprised if your brakes need to be redone.

 

So I got everything done today I thought the axle shafts looked decent no pitting at least by feel they were a little discolored but again didn't feel anything but smooth. Everything went well except for running out of beer halfway through. One interesting thing was when I pulled the drivers side axle the bearings were just kind of hanging out in there not in the ring at all. Thank you glc and roadie you guys were a huge help

 

Did you do seals and bearings both sides?

 

Yes I did didn't see any point in doing just one so I did both seals and bearings... Figured do it once do it right and be done with it and yes both sides

 

Do not use synthetic gear oil. That is the cause of all these LSD's chattering at takeoff (esp. wheels turned or hard launch).
Just use a quality brand 75w-140 (Lucas or Valvoline) and anti-foaming agent (called friction modifier like Motorcraft XL-3).
Synthetic is truly the cause.
Please contact Summit Racing or 4WheelParts for confirmation of the above.
I drained the synthetic in my 2010 from the factory and problem solved.