driveshaft noise

[bryant2482]

I have a single piece driveshaft in my 720. All of a sudden it started making this grinding type of sound. As I increase my speed I feel more vibration coming from it. I pulled it out and there's no physical damage done what so ever. The joints are good, no play in them at all. Not sure where to go from here. Any ideas anyone?

[wayno]

Are you sure it's the drive shaft, does it make noise when sitting still out of gear with the clutch out while idling?

Does the noise go away when you push the clutch in and put it in gear while still sitting still?

[bryant2482]

It only makes the noise when the wheels are turning

[Guest Rick-rat]

Maybe wheel bearings

[Doctor510]

Take the drive shaft out and check the U-joints for play.  The Slip yoke sleeve in the tail-shaft may have shattered.

[bryant2482]

It sounds like its directly below the shifter. I'm wondering too if the output shaft bearing on the tranny is going bad

[datzenmike]

Take the drive shaft out and check the U-joints for play. The Slip yoke sleeve in the tail-shaft may have shattered.

 

Well we have to go with what he has already said about the joints

 

I have a single piece driveshaft in my 720. All of a sudden it started making this grinding type of sound. As I increase my speed I feel more vibration coming from it. I pulled it out and there's no physical damage done what so ever. The joints are good, no play in them at all. Not sure where to go from here. Any ideas anyone?

 

I would do the stuff that is easy and cheap first. This will maybe point to something else.

 

1/ Check the oil level in the transmission. The fill bung is half way up the side (usually the driver's side but can be on the right)The transmission is considered full if the oil is just level with the bottom of the hole. You should easily be able to reach in with your finger and dip into it.

 

2/ Check the differential oil level. The bung is about half way up the back. Again full is level with the bottom of the hole.

 

 

If both are full it's a good indication that they are not making noise from lack of oil.

 

3/ Remove the wheels and drums. Look for something wrong like a shoe may have lost it's anti rattle spring and be rubbing the inside of the drum.

 

4/ lift up on the axle. Is it loose? Does it turn smoothly? Any oil or grease leaks?

[wayno]

The faster you go the louder it gets, as Mike said, check the diff oil, check for color of the oil also, if it's silver, you need to start looking for another one.

[bryant2482]

Well I've already had it up on jacks. When I spin the rear wheels its smooth and there's no noise coming from the axle or diff. The oil levels are good, already checked.

[wayno]

Well there is no "rear" bearing in the tailshaft, it's a bushing, there are bearings farther in near the middle though.

Does the noise/vibration change when you shift gears, or does it just sound a little different the faster you go?

What about oil color?

The place the noise is coming from is what is confusing, if it was coming from the front case of the tranny, I would say front clustergear bearing, it can cause noise and vibration, but it usually also makes noise anytime the input shaft of the transmission is turning, and it can get ugly fast.

[datzenmike]

Any chance the exhaust pipe is resting against the trans, torsion bar, frame or body? Give it a good shake.

 

What about coasting in neutral, clutch pedal up and engine off?? This would stop the counter shaft from turning but leave the mainshaft. If still noisy it eliminates the front main and counter bearings and anything on the counter shaft.

[bryant2482]

It will make noise from time to time when coasting. But most of the time when its in gear. It makes the noise from 1st gear all the way to 5th. Doesn't do it in reverse though. Oh and I will add that there will be times where it doesn't make a sound! But 3/4 of the time its just awful to listen to

[wayno]

The guy in this thread kept driving his truck while it made noise, it bit him in the ass big time.

http://community.ratsun.net/topic/64732-fs5w71b-transmission-troubles-need-some-input/

If it's not the driveline(all U-joints are good), and it not the rearend(no slop in the pinion flange, and the gear oil color is good), then it must be the transmission, so you need to make a big effort to change all the fluids and see what color the gear oils in the rearend and tranny are, because something is wrong with one of them, do you want to be on the side of the road somewhere needing a tow?

I would check the rearend fluid first, as it is the easiest, and noise can travel up the driveline and make it sound like it is the driveline, check the driveline again also, take it out and reef on them U-joints, a dry one can make noise also, but it would likely be stiff(hard to move), or very loose, I have checked my driveline in the past without removing it, I could not tell anything was bad, but when removed it was obvious, then I would check/change the transmission fluid, if you have bearings and chunks of metal connected to the magnet, then you know your issue.

[datzenmike]

True. The picture above transmission I drained and the oil was silver gray like model paint. Three ball bearins fell out with it... you can see the inner baring race on the front of the broken counter. I had hoped to scoop a good spare 5 speed but this was likely why the truck had been parked so long befor being scrapped. It was covered in west coast mould. Motor was probably a good one.

[bryant2482]

ok so i figured out whats going on. either my driveshaft is tweeked or the joint that bolts to pinion gear is done. i can spin the driveshaft and can see where its unbalanced. not sure what its gonna cost to have one built and im not sure if i want to settle on a junk yard driveshaft either

[datzenmike]

The only joint at the pinion is the U joint and it's replaceable. Everything else on the driveshaft is solid metal.

 

If there is wobbling then...

 

a/  The shaft was hit and damaged, maybe bent. It will spin smoothly but look like a skipping rope.

b/  U joint(s) are bad or damaged allowing the driveshaft to be off center and wobble.

c/  The flange bearing is pooched. The differential flange should not move except to rotate. If the bearing is bad it will off center the back of the driveshaft even if the U joint is good.

[bryant2482]

the u-joint on the diff. flange is toasted! it cant move free for shit! time to replace!

[datzenmike]

I have a single piece driveshaft in my 720. All of a sudden it started making this grinding type of sound. As I increase my speed I feel more vibration coming from it. I pulled it out and there's no physical damage done what so ever. The joints are good, no play in them at all. Not sure where to go from here. Any ideas anyone?

 

 

Well this is all we have to go on.

 

Doctor: 'Do you have a headache?"

Patient: "No, I checked"

 

Week later...

Patient: "I found the problem doctor. I have a headache!"

 

:lol:

[bryant2482]

Yea yea I know hah! But I will say it wasn't like that the first time I pulled it out. Obviously it became worse as I kept driving it

[datzenmike]

This happens and if left it will only damage the yoke if you are lucky. There is a lot of stored energy in that spinning driveshaft... lots

[bryant2482]

well all is good now! new u joints fixed it all :thumbup:

[wayno]

All is good, that is music to my ears, so if I am following you down the freeway, I don't have to worry about big chunks of metal coming out from under your truck. :lol:

Really though, feels good to have it fixed, doesn't it.  :thumbup:

[datzenmike]

Yeah, because now you can relax your pucker because it's not likely 30 pounds of steel spinning at 4,000 RPMs isn't going to slice through your part filled 16 gallon gas tank just 4 inches away.

[ryanthomas1]

There are driveline shops that can straighten shafts , here in SD we have Dakota driveline pros who did great work on my friends aluminum driveshaft , he bent and slightly twisted it pulling a heavy load , they bent it back and welded in a new section and so far so good. You could find a drive shaft similar as have it cut to sized and the ends of yours welded on to fit the input and output shafts , just a thought :)