Rear diff lube change interval on Crown Vic

[bdcardinal]

Originally Posted By: wtd
Ok, I didn't know that. I wonder why they say to add it?

Wayne


Lowest Common Denominator, it is easier to just train people to add it and not think.

 

[Raybo]

Had a 98 PI for about 10 years. Checked the diff and it was a choc milkshake at 50K.

Use the Mobil 1 75-140 LS which has the friction modifier already in it but go to the Ford parts counter and buy the little bottle of friction modifier and add about 1/2 that little bottle too. The PI rear end likes the fm.

I recommend changing the pumpkin every 50K at the minimum. I changed mine again at 100K and it was a milkshake then too. That heavy car is hard on the rear end.

Go on the Crown Vic forum as there's alot of info on there. I forget the name now but google it and its the first one they list.

 

[Bror Jace]

"I recommend changing the pumpkin every 50K at the minimum. I changed mine again at 100K and it was a milkshake then too. That heavy car is hard on the rear end."

Agree.

On any rear end I would change it on the early side ... 10,000 - 25,000 miles. That gets rid of the massive amount of break-in debris that forms an abrasive slurry if left in the diff.

Maybe you would have no problems with the diff if the factory fill was left in for the recommended 150K. But if you are already under the car, an early diff change is cheap insurance ... the cost of a quart or two of fluid and possibly a gasket.

Once you start hearing noise (howling, etc ...) it's too late and you'll need an expensive rebuild.