Well, I posted here months ago about my "dreaded" rear end shudder. After reading post after post with results ranging from taking truck in to have fixed only to have shudder show back up, to some shudder is normal for a LS rear end, I decided to wait a while. Low and behold the shudder has disappeared @ 7,000 miles? Every once in a while I can feel it grab, but it is not near as bad as before when the hole rear end felt like it was coming apart on a cold start.

So, is this a "break in" situation, or can I expect shudder to come back? I still am somewhat uneasy about the potential for rear end problems down the road. However, if this is somewhat the nature of the beast, I can live with it like it is now.

 

Good question.. I'd like to know the answer myself.

https://www.f150online.com/galleries....cfm?gnum=4362

 

Mine has gone away too. However I tried a home-made remedy. At the suggestion of another member, I forgot his name, I read that he replaced his rear diff fluid with Royal Purple 75w90. Expensive stuff, @ $8 a quart, but supposedly well worth it. I chose to do it because I lifted my truck, and I was trying to avoid having to talk Ford into warrantying it.

Ever since... no shudder. Although I must say that the severity of the problem seemed to the correlate with temperature; being worst when cold. And it has been hot as hell lately in Nothern Cali.

If anyone else wants to try it I would recommend giving it a shot. The 3.55 and 3.73's require 3 one quart bottles, the 4.10 needs 4 quarts I believe. You also need RTV sealant to make the gasket around the diff cover, a rubber mallet to pound off the cover from the old gasket's seal, and also a 1/2" ratchet drive with no socket works good to take out the fill hole plug. Hope that helps.

 

Why do you want to take a chance..Ford will replace your clutch packs. ALso the bad ones contaminate the diff fluid .

 

I also had a shudder every morning as I drove foward and turned out of my driveway since purchace in Dec 03. It must correlate with outside temp. I have not noticed it once since it warmed up here in Georgia. I now have about 12K. I guess it could have "broken in", but we will see this winter.

I do think that hovbuild has a good point, though. I'll keep checking this thread for updates.

 

funny, I asked a buddy of mine who has been modding mustangs and fords for a long time about the 'shudder' and before I got done asking him he was talking about friction modifier and limited slips...hmmm.

 

I had the shudder bad and was following this thread. Mine has gone away as well and it has been cold here(it happened when it was cold before). The service dept did add friction modifier, he said it was made out of whale fat.
Any way we have had ice/snow on the ground lately and I've been toying around. My question is, what is the LS supposed to feel like when working properly??? When i had the shudder, it was supposed to be the clutches working too good, now I don't really feel anything other than my tires spinning. Did they get worn down when i had the shudder and are not working properly now??

 

I had the same problem with my LS, took the tsb to my dealer, no questions asked, they changed the clutch packs, new fluid and friction modifier. NO longer a problem. Get it fixed while under warrenty. It will probably cost a lot in the long run if you dont.

 

Do you have the TSB numer on hand? I am taking my 04 FX4 to the dealer today and the numer would really come in handy.

Thanks,

Arturo

 

Aurturo,

I dont have it on hand, but you can see all tsb's on the Kelly Blue Book web site, check it out. By the way, the factory warranty cost on my receipt was $519.

 

BEW119,

Where do you find the TSB's on the Kelly Blue Book web site? Thanks.

 

Now for the rest of the story: Had clutch packs replaced and shudder went away. Had rear end pinion and seal replaced and howl went away. Less than 1,300 miles later, rear end shudder is back and a new rear end "whine" is hearable. I am really getting tired of this!

 

I just took my truck yesterday to the dealer. I mentioned the TSBs and the guy was like OK, we'll check it out...

Today I went to take a look at my truck, the 10,000 KMS service was already done and they were just waiting for the "FORD engineer" to come and see my truck to determine what the problem is. The mechanic told me that their first thought was that the gearbox was the problem..I was like...

I hope they come out with the real and long lasting solution since not many F150's (LOBOS) are sold here in Mexico City.

Thanks for the info guys!!!

Arturo

 

My mistake, it was on Edmunds.com

www.edmunds.com/maintenance

 

The dealer replaced my clutch pack this morning. When it was complete, the dealer called me and advised that the problem was even worse and they have ordered a complete rear end assembly. It will take from 7 to 12 business days for it to arrive. I could drive it but I think I'll leave it in their way and drive my spare car so they will strive to get it out of their way.