Hello, I have a o1' screw 4X4. Whenever (Usally after long trips) I turn around a corner, there a vibrations coming form the rear end it seems like. I already had the ring and pinions replaced, but it still vibrates and shakes during cornering.

I'm trying to think if it makes a sound, and I believe there is a thud, thud, thud sound (hard to tell when Im not in the car to remember what is sounds like). Anyone have this problem before? Or anyone tell me what might be slipping or w/e its doing.

 

Yes, you need some friction modifier or maybe need to change the differential fluid and add a friction modifer until the chattering stops.

http://www.performanceoiltechnology....ch_chatter.htm

 

Temp, if your right, you have no idea how happy I will be. But wouldnt the dealer know what it is, if it is that simple?

 

The dealer might not know. Its so hard to get good help these days.

Im assuming your truck has a Limited Slip Differential?

My truck chatters a bit little lately so I suppose I need a little more friction modifier myself. (They call it chatter but I like to use the term shudder.) It might not be clutch chatter but I could only tell for sure if I drove your truck myself. I am only mentioning a common condition that can occur. Its hard to diagnose noises in a thread because our reference points can vary widely. If you say it barks I might think of a poodle when you were thinking of a coon hound. Get a second opinion.

 

Hmm, not sure if it has LSD. It's a regualr XLT 01' Screw, not the Lariet, or FX4. Could you tell me?

 

Look for the axle code on your door sticker and post the code here.

http://www.ford-trucks.com/article/i...r_Decoder.html

http://www.fordf150.net/howto/decode.php

 

ford had several bulletins for rear diff noise that included updated clutch packs for the limited slip. the noise/vibration was most noticable when diff was hot and under accel or in turns. usally once the noise is there all the friction modifier in the world won't help

 

Well I brought the truck in yesterday. Today I was talking with someone else online who's dad truck did the same thing as mine. This is what he said.

"From what I can remember, the clutch in the rear was broken and frozen up. I'm guessing that when he turned the wheels tried to spin different speeds and that made the clutch in the rear vibrate. If that sounds remotely possible. His truck is the first year of the latest body style, whatever year that was."

Can anyone tell me what this clutch he is talking about in the rear end? His dads truck has LSD too if that helps any.

 

there is a set of clutch packs on each axle shaft that are keyed to the differential carrier. the clutchs are forced tight by a wave spring wanting to make each axle spin at the same time and same speed of the carrier (locked together). when making a turn, one axle needs to turn faster so the clutch pack allows one axles to slip. when the clutches are set up too tight or missing friction modifier, the rear diff will want to stay locked up causing the rear of the vehicle to hop or cause the clutch packs to chatter as they slip. also i didn't see that the you replaced the gears. the tech may have forgotten to put in friction modifier, if so, add some modifier and go to an empty parking lot and drive in figure 8s to work the modifier into the clutch packs. if the clutch packs were set up to tight, then a thinner selective fit washer will need to be installed. also if the fluid is contaminated (water entry from launching boats) it can cause the same problem

 

dwsf150, you have helped alot so far, and yes, I told the mechanic to replace the limited slip oil that you mentioned above, so that should be taken care of, and if not, I will head to the Advance Auto and buy some. I was worried about the clutches, because the guy who owned the f150 said he needed to rebuilt the rear end.

 

Well, I got it back from the shop, new oil and whatnot. I drove it around town, and no problems. Well on my way up to Milwakee (sp) to see the Frozen 4, it started acting up near the end (always after long trips is it the worst). How long should this stuff take to work? It was I think 100 miles from Chicago.

 

I used Amsoil in my rear differential. One bottle was what was recommended but I ended up adding another one. The shudder went away for about a year but now its starting to show up again.

 

like i mentioned earlier, in my experiance once the shudder/vibration is there, all the friction modifier in the world won't help. were the clutch packs replaced when the gears were replaced? also i soak the clutch plates in friction modifier for an hour before i install. i've noticed when i got clutch packs from ford they were updated to new design to help eliminate shudder problem.

 

Whoopie! So now, how much is this going to set me back for the clutch packs?

 

Well, my shudder/vibration did not happen until I switched to the Amsoil so I do believe that certain gear oils enhance the probablilty that the clutches will stick more.

It could be that my problem is really in my U-joints now but I won't know unless I add some more friction modifier.

http://www.popularmechanics.com/auto...t/1272541.html