Intermittent grinding in rear

[ndhoffma]

I just noticed today, at lower throttle in every gear, I get an intermittent grinding noise coming from the area of the rear/diff on the car.

The noise is not too frequent, but pretty concerning. I did a quick check to see if anything in that area is loose & could be causing it but didnt find anything. The noise sounds similar to but a lot less intense as the sound I got when the retaining rings had let go in my old mazda's transmission.

My guess is the diff is busted, but I was wondering if anyone had any experience with this or any suggestions.

 

[Markm70]

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]

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?

 

[Ken04]

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?

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.