Drivetrain thumping

[Kona]

Hey folks, my 91 Ranger 4x4 (4.0L ) just started making a uneven thumping noise at speeds over 25 mph / 40 kph , seems like it is inline with the transmission bell housing (thus posting here ) though a little under the front floor.. No sound at any rpm in 1st 2nd or neutral , sound is there with engine off in neutral coasting . Hubs are free , transfercase in 2whl drive . Transmission was a spare installed about a year and 1/2 ago. We did have problems sliding the shaft into the pilot bushing . I have checked the bottom 4 transmission bolts for tightness and they were good .

 

[Dirtman]

Does your driveshaft have the goofy balancer on it (big disc at the front yoke)?

They are notorious for falling apart and making a clunking / thumping sound.

 

[Curious Hound]

Somebody has taped a cat to your drive shaft. At low rpm, no problem. At higher rpm, centrifugal force throws his tail out so it hits the floorpan. The tail will break off after a week or so and the noise will go away.

 

[Dirtman]

Or that...

 

[Kona]

I did just get brand new tires , a suggestion was separation so I will throw other tires on and check

 

[Shran]

Bad u-joint? Do you still have a two piece rear driveshaft? I just rebuilt a rear two piece that had a locked up u-joint at the t-case... it was so bad that it destroyed the carrier bearing and felt like the front end was coming apart at 5mph and faster.

 

[Kona]

It was a loose chain in the transfer case fyi, the clue was locking the hubs in 2wh drive the noise got less. Drove it that way for about two months before changing the case out!

 

[SenorNoob]

Wow that's a long time between posts!