Hello,

First, I have a 2005 Explorer V6.

I was told at my recent oil change the differential fluid should be replaced. I agreed as it looked very dirty. I never realized in the past they should be changing the rear and front together since it is always 4WD. When I mentioned this to the employee, he said we should change the front then too. I agreed, however, the fill plug was rusted and stripped and needs to be replaced. However, I can't seem to find a replacement plug anywhere. I have tried CarQuest and O'Riley.

Also, if I drive with the windows up, radio off and AC/Heat off, so that the car is as quite as possible, I hear a very faint sound, which sounds like metal on metal. I now realize the front differential fluid has probably never been changed (now my truck has 97k miles). Could this be the faint sound I am hearing?

Any information about replacing the plug or the sound would be great!!

Thanks in advance!!
Jack

 

Typically, the fill plug on the differentials is just a pipe thread plug. If you have it out, take it to your local hardware store and find something that matches. Use Teflon tape or Teflon pipe thread sealer when you install it. Otherwise, just get one from the dealer.

If you're talking about the housing being stripped, then that's a bigger problem.

I wouldn't expect a metal-on-metal sound unless the differential is really low on fluid. I'm pretty certain that the fluid in my '98 wasn't changed prior to me buying it. It had 157k on the clock when I bought it. The front differential doesn't take as much load as the rear.

 

Thanks Mikeman! I just ordered the plug from the dealer for $2 and will check the differential fluid tomorrow.

I was told my front probably should be changed more frequently because my truck is always in 4WD so it takes more a beating than if it was rear 2WD.

I know nothing about cars and might be overreacting about this faint sound too, I don't know.

Thanks again!!

 

The faint sound is more likely to be a wheel bearing or brakes slightly dragging than the front differential.

Did the dealer also recommend changing the transfer case/center VCU fluid at the same time since the "always in AWD" theory would apply to that as well?

The fill plug experience you encountered is why you should always make sure you can get the fill plug loose before pulling the drain plug and draining the fluid.

-Rod

 

"Always in 4WD..."? Do you have a selector switch that reads "Auto 4Hi 4Lo"?