Intermittent grinding in rear

Rear Gear noise

I had a similar problem, when I turned I got a whining noise. Changed the rear diff fluid with a friction modifier and Royal Purple Synthetic diff fluid and the problem is gone.


HTH Mark

ndhoffma said:

I havnt notived this when turning, but since I dont know what fluid the previous owner was using back there, im due for a change on that and the trans fluid soon... hopefully i can see what it might be when I get the cover off.

How is the RP fluid working out? Whats the weight?

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you can do a search on this, but for the trans fluid there is a lot of info that said Ford used the incorrect fluid, and incorrect amount for the ATF that is used in the TR3650. Calls for 3.8 and should be 3.2. And Ford used Mobil 1 ATF and it should be Mercon III. The 3 isn't available anymore so use Mercon V. I had a whirring sound in 2nd and 3rd syncro's that went completely away when I changed the fluid. One trans shop tried to convince me I needed a rebuild. But come to find out all I needed was a fluid change. But FYI the word is to use ONLY regular Mercon V, not RP, or M1 or Amzoil, just off the shelf ATF. Worked for me.