I get a shuddering sensation whenever I go from a stopped position to turning left or right. It does not happen when I go straight. I need some insight to isolate this problem. Is it something in my differential, or do I have a different problem. Please help!

2000 F-150 Flare-side

 

Just a guess but it could be your front wheel bearings.

 

It is the clutch pack in the rear diff, assuming you have a limited slip diff. Has the rears fluid ever been replaced?. If not it might be a good time and make sure the friction modifier is added. To verify if you have the limited slip, check the door tag for the rear axle. If the 2 char code is a letter and a number, it is a limited slip.

 

I had all of my bearings replaced and repacked. The factory bearings wore out because they were made of plastic. The problem still persists! I have not replaced the differential fluid, just topped it off. There isn't any metal shavings on the magnetic differential cap. My rear axle code is H9. I am not sure what all the codes relate to in rings, and gearing, etc., etc.

 

The H9 states you have a 3.55 limited slip differential. How many miles on the vehicle? If at least 60k, it would definitely be worth replacing the fluid an friction modifier.

 

Yeah I have almost twice the mileage. I will give the fluid replacement and friction mod a try. I just hope that will take care of my problem. Thanks!!

 

Might check with the dealer too. I believe they have changed the recommended fluid from 75w90 to 75w140, depending upon what rear you have. The dealer should be able to give you that info and that is probably the best place to get the friction modifier if you are doing this yourself.

 

I drained and replaced the differential lube with 75w140 synthetic diff. lube and friction mod in my rearend yesterday. Drove the truck around a little bit and I still have the shimmy/shake just like before. At times it isn't as noticable but the problem still exists. I'm just wondering, should I check and see if my disc brakes are still turning true?

 

Give it a little time. If that doesn't work itself out, the clutch packs will probably have to be replaced. I would be very surprised if it had anything to do with the brakes.
The fluid change is what fixed my 04, the cheap fix. Sometimes it works and other times, it is a matter of the clutch packs. If anyone else here has ideas, I am sure they will post them.

 

Ok I had the same thing happening to my truck (2001 4x4 screw). I took it into a shop that I trust and they have told be that my rear diff is locked up. And that is what is causing the shudder when you are turning. They are going to replace it for me.
I had just gotten back from about a 300mile trip and it had gotten really bad. There was a grinding/popping noise when I turned. It sounded like gears or something grinding. But it only did it when I would make a turn.

 

Add an extra bottle of friction modifier and do some figure 8's in a parking lot. It worked on my 03. I used the 75/140 Intech synthetic stuff from Walmart. Mine started the shudder at 37,000 miles. I now have 80,000 miles and the shudder has not returned. Maybe the figure 8's on pavement will loosen up those sticking clutch plates. Hope you get as lucky as I did!!!!!

 

Don't do the figure 8's for TOO long or you could burn out the clutch packs.
I thought I had a LS shudder, but it turned out to be a u-joint, when it started to chirp that's what clued me in to that.