Rearend Noise

[Yellowsub1962]

sonds like Ford clutch chatter to me. Did you use the friction modifier right from the get go, or di you just add it when you mentioned above that changed the fluid and tried it? If you ran 2 or 3 K without it in "freeway conditions" without it, you likely glazed the clutches. They should clean up by themselves with a couple more services (2-3K miles ea) and using the FORD additive.

I've run Ford 9" posi units for years in various vehicles, and tried many different additives. The Ford additive was always the one that ran the longest and had the least chatter.

Also as a side note, you will feel less "chatter" with more weight as the load absorbs the vbration. It's still there though and needs to be addressed.

PSD

 

[rsjohnsn]

Update
I have tried multiple different things but the result is always the same. I did use the limited slip additive from the get go but the "chatter" came about 3-4k later. The only time I feel it is when the steering is turned and the truck is rolling at idle, anything above idle and it dissappears. I did not however use the ford additive I used something that Advance Auto sells and yes it says it meets the requirements. I am leaving for a 2k+ trip on Sunday and I will see what happens. If the chatter is still there then I will change again and add the Ford additive. I'm not as worried as I was but I would like to make sure that it is the clutches.

Thanks
Scott

 

[BamaSixGun]

hey rs, remember me, i bought the AIC from ya about 4 months ago.

hows it going, sorry to hear your having trouble with the truck.

out of curiosity, what kind of freight do you haul?

take care.