Body "clunk" from a stop

[Borinqua Bronco]

Hi everyone,
Thanks so much for all of your support for my wiring harness install. It's all done and I'm back on the road to tackling new problems. The latest of which is a clunk sound and what feels like the cab is going to fall of the chassis when I put the Bronco in reverse (AT) or get going from a stop. Any ideas? Thx

 

[Rustytruck]

Check the donuts at the ends of the radius arms. if you loose the center rubber between the mount and arms they get clunky. also check the rubber mounts between the transfer case and the cross member. The bushings mounting the rear springs can get clunky. Of course check the body mounts. some trucks the body mounts rust right through the frame mounts.

 

[Rustytruck]

With the weather coming your way stay safe my friend.

 

[67RT]

U joints?

 

[B RON CO]

Hi, as mentioned, check the radius arm bushings, u joints in the driveshaft (s), which can be very bad if your idle is too high, and may as well check the motor mounts. You can easily check the motor mounts by putting it in gear, hood open, and with your foot firmly on the brake, give it some gas. Try this in drive and reverse. If a motor mount is bad, the engine will lift up and you will see it.
Good luck

 

[needsmoarturbo]

I would 3rd the driveline inspection. Sounds like driveline or maybe the caps at the rear diff, possibly axle wrap related in the rear

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[DirtDonk]

A fourth for the driveshaft. If the splined slip-joint is binding it will release with a bang under acceleration especially and the vehicle will squat all of a sudden accompanied by a pretty loud bang.

But it doesn't usually do it in reverse, so you may have something else going on. Or multiple issues.

So look at the bushings like was said, and the driveshaft (how long since it was greased?) and even look to the rear leaf springs.

If it's just the normal clunk most EB's have with an automatic, see if you can lower the idle a bit to make it less pronounced.

Good luck.

Paul