When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Just had the rear end fluid changed on my 99 EB 4x4. The chattering has not gone away. It only happens when under load and you get on it a bit from a standstill. It happens when turnning as well. On the road and cruise speeds it's fine. The tag on the diff says to use synthetic, do I still need to use the friction modifier? The shop told me that synthetic already has it. Should I siphon out several ounces and add friction modifier to the synthetic??
Still need friction modifier, I think its about a 4 oz. bottle from Ford. I just replaced the fluid and added friction modifier and that didnt resolve the chatter issue. From reading other threads it appears to be clutch packs need to be replaced.
UPDATE: I had a local shop change the rear diff oil and I put in 4oz of Trans-X Limited Slip additive (Stops LS chatter). I still have the chatter. Although I wouldn't call it "chatter" though, what I "hear" is more of a rumbling sound. Now I have read the threads about the "rumble" sound that has been attributed to the transmission oil needing a change, which I had done. The "rumbling" only happens when taking a turn slow, from a stop (worse when loaded), and going up a steep hill slowly. Once you get her going you don't hear a peep, or shall I say feel anything. I know the diff is engaging because I pegged it on some loose gravel and I had 2 patches left behind. What gives? Should I have used a specific modifier, like from Ford? Is the Transfer case the culprit. This is beginning to get frustrating.
This weekend I'm planiing on adding 2 additional 4oz bottles of Motorcraft friction additive. I'll know by Monday what the results are and post them. Just out of curiousity has anyone ever just lived with this problem or ignored this problem and it resulted in some type of major issue?
Is one of your rear tires worn more than the other?
You shouldn't get "chatter" from a limited-slip taking off in a straight line.
Do this: Come to a stop, apply brakes, and tap the gas, yes, power-brake it, without spinning the wheels. Do you hear the chatter? If so, it's not in the rear end. Let off the brake and hit the gas, going in a straight line. Does it chatter? If so, it's not the rear end...
I had the rumble characterized by a slow hard turn when cold. Changed the rear diff oil (put the friction modifier in first) and the problem went away and hasn't returned. There is a TSB on this issue.
i had the same problum they and all at ford thought it was t-mission and wanted to pull it but i found i had broken belts in the rear tires thats your problum changed the tires all rumbleing stoped.
Originally Posted by 1stexpy
UPDATE: I had a local shop change the rear diff oil and I put in 4oz of Trans-X Limited Slip additive (Stops LS chatter). I still have the chatter. Although I wouldn't call it "chatter" though, what I "hear" is more of a rumbling sound. Now I have read the threads about the "rumble" sound that has been attributed to the transmission oil needing a change, which I had done. The "rumbling" only happens when taking a turn slow, from a stop (worse when loaded), and going up a steep hill slowly. Once you get her going you don't hear a peep, or shall I say feel anything. I know the diff is engaging because I pegged it on some loose gravel and I had 2 patches left behind. What gives? Should I have used a specific modifier, like from Ford? Is the Transfer case the culprit. This is beginning to get frustrating.
had same problum they thought it was comeing from some where in the drive trane but it ended up begin broken belts in the rear tires it rumbled at speeds from 35 -45 mph then it stoped,after tires in rear were changed the rumbeling stoped.
The problem we seem to have it not being caused by tires. I also just had new tires installed and I still have the problem. Again this problem it not when going straight. It only occurs when going from a stop and turning in either direction. Its almost feels like a drag, or when your in 4WD
The original poster of this thread mentioned that it also does it on turns, so I assume he's getting it in a straight-line... which is NOT a limited-slip problem.
Anyone who gets it when they take off and turn at the same time, and it doesn't happen when taking off straight, that's gotta be the limited-slip. Or the spider gears are chafed up and making noise.
I'll warn you now - if you have a limited-slip, it's SUPPOSED to feel funny when you make tight turns. A good limited-slip will actually make the inside tire "skip" or make a "scrubbing" sound on dry pavement. In the rain it's even worse. The whole point of a clutch-based limited slip is to impede one wheel spinning more than the other. If the clutches are in good shape, it should feel different than an open diff.
My '01 SD V10 has an LS in the rear. I make a lot of right turns, more so than lefts, and the right rear tire is obviously worn much more than the other side because everytime I take off, that inside tire is trying to spin just as fast as the outside tire, and "scrubbing" the tire.
I checked the u-joints, and maybe I did it wrong, but the way I checked it was to get under there and try to spin it by hand. I couldn't budge it at all. I have to try the suggestion mentioned earlier about applying the brake while tapping on the gas to see if it will happen.
I have a 01 F150 SuperCrew that is also getting chatter from the rear. Had leak on axle cover about 1 month ago. Took off cover and resealed with new silicon, and replaced lube with 75W140 Synthetic. Seemed to have quieted down but since yesterday has gotten worse notice most when driving slow or starting out on an incline. Any suggestions.