Recently when I make left hand turns, it feels like my rear left wheel is dragging or grinding a bit when I accelerate and continues for about 20 feet, then when I straigten out, it goes away. Only there while turning left, nothing happening when I make a right hand turn. Not sure if its the bearings, E-brake? I just had the rear rotors turned? Any suggestions?

 

Sorry, I should have noted that it is a 2000 F150 4X4, 5.4L

 

I would start by checking you rear end. Pretty simple to do by taking off the diff cover and checking your fluid condition and making sure that there is nothing obvious broken or damaged. Is your rear end a limited slip, posi traction, or open?

 

I believe its limited slip. I just had the fluids changed in both the front and rear end. No leaking.

 

who changed the fluids? with it being limited slip there are certain fluids you have to use or certain additives you have to use for the clutches in the rear end. if the correct fluid was used, then either the clutches back there are worn out or your problem may not be in the rear end at all. but i know from experience that they can cause a now like that.

 

go to Auto Zone and get a 7 oz tube of friction modifier for $10. and put it into the rear end with the gear lube. they probably "forgot" to do it.

 

Ditto, to that.

 

Mine did it too after I had to get another rear diff from salvage cause the original got damaged from a spun bearing. The salvage axle had the clutches grinding from just sitting. That additive is essential, just the fluid alone in the diff is not sufficient. I describe it more as a "chatter" vs a grind. After you add the additive, it should slowly improve to eventually being completely gone by a week (50 to 100 miles) It takes some time for the solution to work its way in as there are no pumps like oil and fuel. It just has to splash its way around. I put two tubes in mine by the way.

 

If you do some tight slow speed figure eights in a parking lot it will help to get the additive where it needs to be also.

 

Thanks for all the info. Sorry I didn't reply earlier, but after I posted I've been real busy. I will get some of the additive and add to the diff fluid. Thanks again!

 

I forgot to note that my stepson took the truck into his auto class. They were doing the breaks and I had them do the fluids in the diff since the labor was free, my guess is they may not have put the additive in there because it was not on the bill for materials.

 

Not sure if you all are still reading this thread, but I put some additive in it..Trans-X. It appears to be worse now. I suctioned out about 6oz of the diff fluid, then put about 6oz of additive in it. Ran it down the road a few times, then figured I would drive some today. Today when I started driving it started shaking from the start. I pulled in a parking lot and did some figure 8's as mentioned, and then when down the highway, it was rough shuddering until I slammed on the gas...and it smoothed out, if I let off a bit, then puhed back on at about 60mph, it would shudder. Did I do something wrong? Was I not supposed to remove the 6oz of diff fluid and replace with additive? When I removed the drain plug the diff leaked as the fluid was level with the drain hole? Is there a top plug? I could not see one?

 

That's the correct fluid level. I believe the correct
gear oil for that truck is 75/140 full synthetic. Motorcraft being the ideal gear oil. The conditioner
you put in makes the fluid slicker so that instead of the clutches grabbing they will slip a little. It
takes some time for it to start working sometimes.
If you are still having the problem after driving for
a while then you probably have something else going wrong. Take it to a shop that specializes in
differentials , if it does clear up soon.

 

you dont have an axle problme. The rear differential addative is to stop the jerk or shudder when you turn a sharp corner at low speed. It does nothing at 60 MPH whn you stomp on the throttle.. You mave have converter shudder or another problem. Did they change the transmission oil ?? Did they use MERCON V ? New MERCON V will get rid of "shudder" noted when driving down the road at 40- 60 MPH.

 

are you sure you dont have a COP (coil) misfire?