Once and for all, someone offer a success story on clutch pack replacement in the LS rear ends to solve rear end shudder! I have an Super Crew with 5.4 and 3.55 LS with 2,500 miles. When cold, I can make it shimmy/shudder/bite/clunk, and everything else from a dead start. I have not taken it in yet due to the lack of positive resolve from most posting on this site. I would like to go back to my dealer "loaded for bear" if you will. With all the folks having this same problem, why isn't there a TSB on this yet? What do I do if my dealer is not aware of problem or its fix? When I take it in, I want a speedy fix that is permanent and from what I hear, there are some that have had clutch packs replaced only to have the problem come back, only worse!

So,what is the solution? What is the correct diagnosis? How can one get this obvious problem fixed?

Thanks for the feed back

 

I replaced the factory gear oil with Royal Purple Synthetic Gear Oil. Fixed it right up. There is no way I would trust any rear-end work to any dealer. If one replaces the clutches in the diff one must check and sometimes reset the back-lash of the ring gear. Not really a big deal, but something that your average dealer guy just hasn’t done many of. That’s the main reason you will read many horror stories of folks bringing their trucks in, only to get them back whining and making noise. I’m not going to train any of them on my truck. BTW, yes I am a mechanic or “tech” for a living. ASE Master Tech/L1. Used to work for a Lincoln-Ford dealer.

 

When i worked as a mechanic for GM they had the camaro dothe samething there fix was to change to oil and add a limited slip additive to stop the chatter! It worked then and im gonna do it to mines soon!

 

Repair of my FX4 SCrew with LSD 3.73 was done about 2000 miles ago. The shudder was getting really bad at about the 6000 mile mark but after the repair (by the dealer) it is slick as a whistle. My dealer replaced the clutch pack AND the ring and pinion. You certainly need a tech that knows what he is doing but they are out there. They have a special process to prepare the clutch pack for installation that has to with soaking it in the lubricant before installation. Good luck.

 

04 FX4 Screw.
2000 miles, just started getting the LSD shutter.
I have a good repor with my dealer and I'm having him look into having them do the fix but I'll pay the extra to fit a much better LSD (assuming by the amount of problems with the stock unit it is not up to the job).
I was thinking of a torsion (gear type LSD). Which should also net better performance.
By the way what size rear is on the current F150's with 5.4L motor?
I was thinking of... http://www.powertrax.com/
Anyone have experience with them, thier demo video is quite convencing.

Thanks,

William
Santa Cruz, Ca

 

Had my clutch pack replaced at 2000 miles,, had shudder in rear end turning left ,, dealer rep seemed to know all about the problem and i thought he said there was a tsb on it,, had to make appointment with their rear end mechanic as he was the only one they allowed to work on this problem,, came out great and no problems since,, rep said the clutch material was new and ford is finding out the clutches are not absorbing any oil which is why they are grabbing at take off,, at least thats what they told me,, makes sense though,, they put different material clutch pads in,, i would just make sure they have a good rear end mech working on your truck from a good dealership aware of the problem,, i have had no problems with my dealer fixing problems with my truck,, but have found that some reps know more about the new f150 than others,, good luck,, john

 

I had mine in to the dealer also, he did a test on the rear end tires, he said he was able to check the clutches by turning one tire and measuring the weight it took to break free or something like that, anyway he said it was to spec and checked the spline and slip yok, he said the spline had metal shavings on it and cleaned it up, greased it, ordered me a new spline and sent me off. new spline isn't in yet but when i took the truck, i didn't feel any shudder, thought it was fixed and then later that day, started noticing it again, now its just like before.

The clutch material not soaking oil thing seems like a real answer to the shudder problem though.