anyone else here with the limited slip rear end notice any shudder from their axle when starting from a stop on a turn. i just stared noticing this lately. i know that occasionally you have to add friction modifiers to ls rear ends, but this seems kinda early since my truck doesn't even have 4k miles yet.

 

TroyK

I think it's normal my supercrew has been doing that since day one and now has 29000 on it and I especially notice it in the rain taking off. It still works I leave two black patches at most every light around.

I am pretty hard on it

So I am not going to worry about it.

But the lash adjusters now that's a different story!!

 

I noticed the same thing. Only happens when accelerating during a turn from a stop with my trailer in tow (about 4,00lbs.) Was going to have it checked when I have the head oil leak done. I figured they were going to say normal and NFP. I guess misery loves company.

 

I have this issue too. I also agree that it seems to be LS behavior. I actually like driving trucks with a more agressive limited slip. It can make some (of my) winter manuvers easier. I also have a truck with a Detriot locker in it, so the limited slip chatter seems almost normal.

My only worry is that the chatter will impact the longevity of the LS. My last 2 new style F150's did not do this.

 

i don't notice any chatter noises with mine, just the hoppy/shuddery feeling at launch in a turn. anyhoo, i asked one of the guys at the local service department about it, and he said they'll put in a friction modifier and that helps alot. he also said they usually don't see this on the f150...more common on the f250...interesting!

 

Hey Troy,

Interesting findings there. How much would the friction modifier be and, for that case, what does that do? I drove mine for about two hours this afternoon and I don't think mine did the 'thunk' a single time. Weird how it's an 'off and on' problem.

Thanks for the info. When I go in for my next oil change, I'm going to ask about it. It'll be interesting to see if I get a similar answer.

 

I guess i should have looked here first! I just posted this question in the Other Drivetrain section. I have the shudder also. I have about 22,000 mi on it. Just recently started doing it. I find it hard to believe that this is a "normal" behavior. Sounds like another nice Ford quality problem. I too am concerned about the life of the LS if this is already occuring. Maybe i'mf being too paranoid?

Tony

 

rockpick,

i had made an appointment to take the truck in for the driveline shudder and axle hopping. however, something came up and i wasn't able to take it in. i plan to do it soon, though.

when i made the appointment i asked the guy at the service desk about the limited slip hopping. he said folks with f250s have complained about it but he didn't remember anyone with an f150 complaining about it. anyway, this friction modifier stuff comes in small bottle and they just dump it into the grease opening on the axle. i don't think it costs too much. i remember having to put the stuff in my 77 cordoba after it started making humming noises going around corners. anyhoo, i haven't heard any noises from my truck's axle, just felt the hopping stuff...

hopefully i'll be able to get this done before the end of april...

 

I had the friction stuff put in about 2 months ago (3500 miles) as my rear end (trucks rear end) was shuddering also. After the friction stuff was put in it seems to have helped. I have only noticed a shudder one or twice since.

 

Mine does it too. I thought it was just sand or dirt on the road. I do not remember it doing it new. I plan on changing the fluid to see if it helps. The friction modifier should be good for the life of the fluid.

 

I'm actually guessing they forgot the friction modifier. I happen to have a tube in my garage - I may just give it a try tonight. There aren't any funky fluid concerns with the rear axle are there? Just thought I'd ask after the 5w20 SemiSynth and Mercon V stuff ...

 

I wish I had this info a few months ago......I had noticed a little extra lubrication on the inside of 1 of my rear tires to find that I had a BAD axel seal...so I dropped it off to the EXPERTS? at North Central Mass' finest FORD establishment and the,...Lets call him a Technician for the time being, put regular diff fluid Not the Synthetic that is required. If you guys would like to experience a chudder (chatter/shudder for you southern boys'.....60 min still a 2-hour program down there? ) anyways it has been rebuilt twice and still not satisfied with the results. If there is a fix Please let it be soon

 

dropeed the truck off today for the shudder problem and some external door molding warrany work. The service guy knew exactly what i was talking about when i mentioned the shuddering thing. He described it to me before i said anything. He acted like this happens alot, and said they drain the fluid, and then add friction modifier to it again. So, hopefully, this will do the trick. If your truck's out of warranty, it at least sounds like a pretty simple do it yourself repair.

Tony

 

I added the friction modifier last night at my 3000 mile oil change. It fixed the problem on my truck that has existed since I bought it. It was always really bad on sharp turn starts in the rain. Today it rained, and I drove several hundred miles for work. No symptoms at all.

I suspect they Ford failed to add the modifier when they made the truck. My last two Fords had limited slips and never showed the behavior. At only 3000 miles the fluid should be just fine, so I know it is not worn out yet.

I hope the problem doesn't return, and I hope there is no damage from the chattering. All I can say is that I am happy.

 

Actually yes the rear diff uses a abnormal type of fluid as well. For the 97+ F150's you need to use 75w140 synthetic and if it's a LS rearend you have to add the friction modifer. The only people I know of that make this fluid is Ford/Motorcraft, Amsoil (does not need the friction modifer), Royal Purple, Richmond, and maybe Redline.