When I am accelerating from a stop and turning a corner, there is a slight shudder that seems to come from the rear end area (not sure though) Has any body else experienced this or know what it could be?
Thanx...

 

If you have a lim slip rear I'll bet you that's what is going on.

 

Had the same feeling with my 99 F250. I changed the rear differential fluid (I also added a bigger aluminum cover), added the proper amount of friction modifier and no more feeling.

I added the cover for ease of changing fluid later and I tow most of the time, so aluminum cover and more fluid equals lower rear dif temps.

Toyman

 

This happened to me two days ago. But it didnt happen to me when i was taking turns. Whenever i accelerated or went 75mph over the highway it would make that noise. Changed the rear diff oil with Royal purple 75w 140 and it went away.

 

Thanx for the replies... will look at changing the rear diff fluid in the new year.

ScottieHottie, what did you mean by your response? that I need new fluid/friction modifyer or something else could be wrong?

Btw, how would I know if I have a LSD? Thanx

 

if you have the original build sheet, it should say, otherwise try posting axle codes (the metal tag on the diff) or maybe the door sticker and hopefully someone here will decode it for you.

Good luck!

Isaac

 

Buy a bottle of friction modifyer from ford and your chatter will go away. Scotty is right.

 

What kind of damage can be done until i can get it fixed? Should i minimize the amount I drive it?

 

No damage, It is just the clutches in the rear end grabing a little more then they need to.

 

Cool....

Thanx!

 

What are the metal tag codes on your truck. I can get them looked up for you. Also they are right about friction modifyer.

 

RE: Rear end shudder but on a 98 Expy.

Seems the diagnosis for this is fluid level and or modifier WITH limited slip diffs. I have the shudder/grabbing at low speed turns and it reverbs through drive train but I don't think I have a limited slip.???? I did have rear diff fluid changed 6 months ago by a questionable shop. (Everywhere they went more issues arose). Anyway, I'll check for proper fluid level and try the modifier but has anyone had this with my year model?

Thanks for all this forum provides. I've 129K on my 98 EB & honestly until I had PREVENTATIVE maint done I have had little issues at all.

Oh yeah, electric shift motor did crap out and had that changed.

 

As a follow-up, I changed the fluid out to Royal Purple (actually quite a bit less expensive than the dealer fluid). The shuddering didn't go away right away which kind of worried me but after a few days it did. Nice thing with the RP is you don't have to guess how much modifier to put in.

 

Canadian I would love to see a pic of your blacked our X.

 

It's not the best for showin right now... besides being winter dirty all the time right now, I have body issues that need attending to (peeling paint around doors, dented fenders and bumpers, etc...) I will be posting something up in due time...

I'll give you a hint what it looks like though... it's big, black and blocks the sun like an eclipse...hehehe