Break question.

[GoToGuy]

Right an out of balance of a few grams or an ounce multiplied by centrifugal forces turns into pounds of out of balance forces. And or causes rapid part wear and tear to failure. A driveshaft failure at highway speed a very bad day.

 

[GoToGuy]

You might also look at the rear axle, high mileage, hard truck life the ring & pinion can develop a clunk or bump noise as it loads or unloads power back and fourth. Yoke, u-joints, double cardin, ring & pinion. Worn disc brake pads shifting within caliper. Areas to help your diagnosis. Good luck.

 

[sync]

What's the vehicle? Sometimes when you apply the brakes theres a clunk coming from the driveshaft. Gm very popular for this

Mine does this if you blip the throttle in gear. My old Blazer done the same. Slack in the drive train somewhere.

 

[Supercharged111]

Mine does this if you blip the throttle in gear. My old Blazer done the same. Slack in the drive train somewhere.

In mine it's the rear diff(s).

 

[Schurkey]

Here's a recent Speed-Talk post about driveshaft critical speed, complete with a broken driveshaft that destroyed the transmission.

Idiot removed a two-piece shaft, installed a one-piece shaft with his LS engine/trans. Got what he deserved.

Drive Shaft Failure? - Don Terrill’s Speed-Talk

One of the posts has a critical-speed chart for the company's (Mark Williams, MW) shaft part numbers.

 

[SUBURBAN5]

Mine does this if you blip the throttle in gear. My old Blazer done the same. Slack in the drive train somewhere.

Mine does it too. I'm sure I need a diff rebuild soon. The plan is to swap to a 373 ls when it goes

 

[454cid]

Here's a recent Speed-Talk post about driveshaft critical speed, complete with a broken driveshaft that destroyed the transmission.

Idiot removed a two-piece shaft, installed a one-piece shaft with his LS engine/trans. Got what he deserved.

Drive Shaft Failure? - Don Terrill’s Speed-Talk

One of the posts has a critical-speed chart for the company's (Mark Williams, MW) shaft part numbers.

I don't know why GM would use a two-piece on a truck that short. Maybe they had to, due to lack of precision back then... according to some of the things I've heard, I'm betting that's the case.

I wouldn't hesitate to swap in a single piece shaft, but it wouldn't be only 3" in diameter the full length of the shaft. Those 3" shafts are always kept short by GM. Even if 3" on the ends, they normally have a greater diameter a few inches in..... swaged tubes.

I'm not sure why you think he deserved to have it blow up, because he trusted a driveshaft shop to build him a proper driveshaft.

I'm not seeing a Mark Williams, MW or a chart, did you post the right thread?

 

[Aqua]

Want to thank you all! I have starting points where to look and diagnose. Cheers!

 

[Schurkey]

I wouldn't hesitate to swap in a single piece shaft, but it wouldn't be only 3" in diameter the full length of the shaft. Those 3" shafts are always kept short by GM. Even if 3" on the ends, they normally have a greater diameter a few inches in..... swaged tubes.

I'm not sure why you think he deserved to have it blow up, because he trusted a driveshaft shop to build him a proper driveshaft.

Take out a two-piece, put in a one-piece, small-diameter, bottom-feeder shaft...get shafted.

If you're going to re-engineer the vehicle on your own, you'd better know enough about engineering to not get into trouble.

Yeah, the driveshaft shop he trusted has some responsibility, too.

I'm not seeing a Mark Williams, MW or a chart, did you post the right thread?

It's in that thread, but I didn't re-post it here until now:

You must be registered for see images

[Edit] It shows up for me while I'm working on this post, but as soon as I save the post, it's a broken link. I guess you'll just have to look at the second-to-last post on the first page of that thread. (Posted by "VMC") [/Edit]

 

[Supercharged111]

Since aluminum is weaker than steel, it needs to be larger in diameter to survive. The net result is still a driveshaft with higher critical speed. Strength and weight both work against a driveshaft WRT its critical speed.