I have a '99 Nav 5.4 w/ 88K miles on it and the trans recently went. I had it rebuilt for $2,400 and got it back and immediately heard a whining sound. The shop said it was the front diff. at the time. I took it back after 1,500 mi. to have them check the whine out and they said again it is the front diff bearing. Do Navs have probs. w/ the front diff bearings going at 88K miles? Could the new trans be putting "more torque/pressure" on the front diff causing the whine and the old trans not cause the front diff to whine? Any ideas? Thanks in advance!

 

bump, as I'm interested in hearing about this as well.

 

Do the gaters have all wheel drive?

Adrianspeeder

 

Yes, it's AWD.

 

Well, take out the front driveshaft and go for a drive to see if the whine stops. If it's still there, ain't the front diff, assuming the center axle disconnect isn't locked.

Adrianspeeder

 

I was told I can't just pull the front ds out and take it for a test drive since it's AWD.

 

On a 99 Navigator, it *should* have the automatic 4 wheel drive with a selectable transfer case just like the Explorers (4auto, 4high, 4low), not a true AWD. There is a direct mechanical link between the input shaft and the rear output shaft, so pulling the front driveshaft should not be an issue. However, it's only going to tell you if the squeaking is being caused by the front driveshaft. The front axle assembly is a live axle and turns at all times, so even with the front d/s removed, the front axle components will still be spinning.

-Joe

 

The Nav "default" is 4auto like you said. There's no 2wd or anything. I see your point about the ds whine though, guess pulling it won't tell me anything except whether it's the ds or u-joints.

 

Oh, and it's not technically AWD, it's automatic 4 wheel drive. Big difference...

-Joe