Clunking sound

[joe o]

I have a 1999 exp and it's been making a clunking sound when you are going any speed and get on the gas to pass someone also noticed it when pulling my camper and going up a hill or getting on the highway. It sounded like it was coming from the transfer case / front drive shaft area. I took off the front drive shaft to see if the u joints were bad but they seem fine. I took fuse 104 out and drove it with out the front drive shaft and no clunking. Already replaced cv axles and wheel bearings seem fine. Not sure where it is coming from. Either front differential or transfer case. With the front drive shaft in it was driving fine just when you got on the gas.

 

[LameSuburbanDad]

Open the service port on the front axle. Stick a pinky inside and feel around. Does any amount of fluid come out on your pinky? If not, your front diff is low. And may have burned up if it was left low for too long. Some plugs have a magnet, check for metal filings as you would the oil drain plug. Fill if necessary and replace the service plug. Hope it helps....but it does sound like (if all cv, bearings, u-joints etc. are good) you might have hurt the pinion or it's bearing.
Please bear in mind that I'm just a lame, suburban dad, and not an expert.

 

[whtbronco]

You could also check the transfer case for play. Hold the rear driveshaft still and try to rotate the front driveshaft output. There should be very little play between the 2, just a tiny bit of chain slack.