2005 4.7 4x4 SLT

So my truck has had a leak in the pinion bearing seal For some time now and like a dumb *** I never checked the oil level in the diff because I've never really seen a puddle or it drip.

Well now when I shift back into forward from reverse I hear/feel a "clunk". And sometimes when the trucks shifts going up a steep grade I also feel a clunk.

I had someone watching the drive shaft when I went from reverse to forward and they said it seen like there is a lot of play before it finds a gear.

A few days ago I checked the oil level in my rear diff to find out it was one and a half quarts low so I filled it up with 75 140. Same thing happens. ..

I am assuming that the damage has been done but what do you guys think it is?

Has this happend to any of you?

 

Is it in the diff, or is it the U-joints?

I'd check that first.

Which reminds me - *makes note to top off Cougar soonest due to ITS pinion seal leak*

RwP

 

My first thought was the u joints but after inspection they look good although they do look like the stock ones.

I'm leaning towards the diff because I drove it for so long with the leak without checking oil level.

 

Don't forget to check the U joints and CVs on the front suspension.

The key is to check the shaft/yoke or shaft/flange joints, to see if the clunk is because of the driveshaft shifting in the yoke or flange, or if the yoke or flange is shifting with the driveshaft (putting the clunk in the diff or transmission, depending on which end of the driveshaft is or isn't moving).

Again, before I worried about the diff (there's not much that CAN clunk like that inside one if it's still working!), I'd be doing U-joints and/or CVs (didn't notice the 4x4 before).

RwP

 

it's going into the shop on Thursday to get diagnosed.......

 

i would look at the front drive shaft but i would also take a look to see if the transfer case fluid has ever been changed or checked.