Hi to All:
This is my first post but I've been using the great information I find here for years!!


My Dak: 2003 Club Cab Sport 4X2, 3.9L SMIP V6, Transmission 4-Spd. Auto 42RE, Rear-end MDM 3.55 "Non-LSD". With 33,000 miles on it.


My Problem:

I hear a Thud or Thump or Clunk that sounds like it's coming from behind the drivers area. This happens while at a constant speed between 30-50 MPH, driving straight and not around the transmission shifting. When it happens I can't feel any power change/loss. It's happened about 10 times now I'm afraid to drive my truck.


Efforts to date:

Jumped up and down on the back bumper, pushed and pulled the bed side to side; No sound.
Jacked up the rear-end W/Trans in Park spun one tire, spun both tires, W/Trans in Neutral same drill; No sound.
Checked break pad, rotor and caliper for stuck, broken or leaking all seem fine.
Pushed, pulled and rotated drive shaft U-Joints seems fine, No sound.
Pulled the Diff cover inspected all gears nothing, looked for metal on the magnate nothing; changed fluid to Mobil-1 Synthetic 75W-90 LS.


Went for a test run about 5 minuets in and the "Thud/Thump/Clunk" happened twice!! I'm stumped!!


Any help is greatly appreciated;
Thanks Paul

 

check your driveline at all

 

You sure your not hearing a front end clunk? also check the exhaust to see if it loose