Driveshaft vibration

[SirRobyn0]

Update: Well at this point I can firmly say that this is some sort of balance issue as the screw clamps have made improvements if nothing less. This morning I took the clamp by the transmission off and drove it to work. The vibration was obviously worse than last night with the clamp. At lunch today I put two clamps on in the same spot on the upper shaft, drove it, wasn't happy, spread the clamps about 35 - 40 degrees apart, drove it and it felt like the best it has been so far. But now I feel I can feel some vibration from behind me so I put the clamp on the back shaft in the position I marked and it is now the best it has been so far. I'm not saying it's as good as a driveline shop could get it, but it's definitely much improved. I have to make a short freeway run tonight and I'll get a good run at various speeds in varying terrain so I should have a better idea where I'm at after tonight.

 

[Snoots]

Could be an out-of-balance driveshaft.
Could be bad U-Joints.
Could be driveshaft angle, caused by bad tranny mounts; etc.

 

[Craig 85]

Here's my last thought. Are the driveshaft tubes straight? Maybe put it up on jack stand and put it in gear and see if there is any wobble or put a straight edge to them.

 

[SirRobyn0]

Here's my last thought. Are the driveshaft tubes straight? Maybe put it up on jack stand and put it in gear and see if there is any wobble or put a straight edge to them.

Funny I was just thinking that on my drive home tonight. Actually I was thinking why didn't I check it when I was doing the U-joints.

So I've fiddled with the screw clamp hose clamp thing and I don't know.... It sucks really. Seems like I can make some improvement, but not really get it anywhere near close enough for me. I realize my balance method is pretty low brow, but still. If it's got a bent shaft that would never run vibration free.

 

[SirRobyn0]

I did not get the chance this weekend to look at the driveshafts, it's spring on the farm and that keeps me pretty busy when I'm not working the day job.

I did drive the truck some. If it has to be like this I can live with it for a while, but I will take a look and see if any of the shafts are bent this week and report back when I finally get to do it.

 

[SirRobyn0]

Side question. So lets assume for a minute that I find one of the shafts bent (remember this is a 2 piece rear shaft). My understanding is that each shaft is balanced separately, is that correct? If so knowing I'm not thrilled with the local driveline shop, could I potentially just replace one shaft with a used one if I can find one? Or ya'll think I'm just asking for continued vibration going that route.

 

[82TwoHeadlight]

I had the same issue on a similar combination. After replacing u joints, carrier bearings, wheels and tires, the fix was the transmission tailshaft. A 700 r4 has a bushing in the tailshaft that the front driveshaft yoke rides in. The bushing will wear when things are out of balance. When the balance is corrected the vibration won't go away completely until the bushing is replaced.

 

[DoubleDingo]

If you have a gopro, clamp that sucker under the truck and drive it. You'll be amazed what you see while you drive around. You'll know right away if the driveshaft is bent, if a yoke is messed up, center bearing messed up, rear bushing on trans messed up, motor mounts sloppy, transmission mount shot, rear spring bushing shots, etc. Even if you have a way mount your phone, do that. Or, find a homeless dude and have him hang under there while you drive and if he survives, he can tell you all about what he saw...lol...

 

[SirRobyn0]

If you have a gopro, clamp that sucker under the truck and drive it. You'll be amazed what you see while you drive around. You'll know right away if the driveshaft is bent, if a yoke is messed up, center bearing messed up, rear bushing on trans messed up, motor mounts sloppy, transmission mount shot, rear spring bushing shots, etc. Even if you have a way mount your phone, do that. Or, find a homeless dude and have him hang under there while you drive and if he survives, he can tell you all about what he saw...lol...

This is one of those moments when I say why didn't I think of that.... Great idea, yes I have a gopro, and a clamp I'll have to try this.

 

[DoubleDingo]

Can't wait to hear what you find

 

[peats]

have you checked the converter bolts for tightness and uniform weight? i learned from trial and error on a driveline shake on my 72 k5 when i got it off of ebay

 

[SirRobyn0]

Can't wait to hear what you find

Of course. If I get any interesting to look at video I'll post it.

have you checked the converter bolts for tightness and uniform weight? i learned from trial and error on a driveline shake on my 72 k5 when i got it off of ebay

No I have not. Also I do not think that is it. The reason I say that is anytime I have run into something like that in the past the vibration would also be present when not in driving, such as reving the engine to the RPM of the vibration while in neutral. I think this is good advise and something that should not be over looked in a vibration scenario, but I think it's unlikely in my case.

 

[Craig 85]

have you checked the converter bolts for tightness and uniform weight? i learned from trial and error on a driveline shake on my 72 k5 when i got it off of ebay

I bought an '87 R30 in 1991 that had this weird chip when you started it. Turned out it was the torque converter bolts has loosened. Well being young and dumb back then, I just torqued them down and ran it. It turned out the holes in the flex plate oblonged and things weren't true. I had a harmonic vibration starting between 65-70 MPH. When I pulled it out of gear at speed, it would go away. I sold the truck before it got dealt with.

 

[Raider L]

@82TwoHeadlight,

Funny you should mention about the trans shaft bearing, I was reading a off road mag last night and in it was an article about a tail housing for a 700R4 that you could buy that had roller bearings in it, one at the end of the tail housing end that bolts to the trans, and another one at the other end of the tail housing at the slip yoke. The bearings were the long cylindrical shaped roller bearings in a cage. They replaced the bushing bearings at that end of the stock housing. You had to buy their housing and the bearings came in it.

Reading this thread, how much vibration is it? Is the steering wheel shaking? Can you see it in any way? Could you put a cup of water in a holder on the dash and see the water rippling? I've not had any problem like that, I've got a long bed, except for a long time ago when my "swing" bearing was about to fall out of the truck. Is that what ya'll are calling a "carrier" bearing? The assembly that is in the middle of the short shaft coming from the slip yoke back to this assembly and then after that there is a long slip unit that the long drive shaft is connected to with a u-joint, then back to the rear end. My "swing" bearing is a rubber thing encased roller bearing that is pressed over the shaft that comes in a bracket that bolts to a cross member under there. That thing?

Yeah, that's what was vibrating and about to fall apart. The rubber and the bearing had disintegrated and was making a lot of racket under the truck. The guy at the repair shop said, "How the hell did you drive it like that? When we unbolted the bracket from the cross member it all fell onto the floor!"

 

[SirRobyn0]

@82TwoHeadlight,

Funny you should mention about the trans shaft bearing, I was reading a off road mag last night and in it was an article about a tail housing for a 700R4 that you could buy that had roller bearings in it, one at the end of the tail housing end that bolts to the trans, and another one at the other end of the tail housing at the slip yoke. The bearings were the long cylindrical shaped roller bearings in a cage. They replaced the bushing bearings at that end of the stock housing. You had to buy their housing and the bearings came in it.

Reading this thread, how much vibration is it? Is the steering wheel shaking? Can you see it in any way? Could you put a cup of water in a holder on the dash and see the water rippling? I've not had any problem like that, I've got a long bed, except for a long time ago when my "swing" bearing was about to fall out of the truck. Is that what ya'll are calling a "carrier" bearing? The assembly that is in the middle of the short shaft coming from the slip yoke back to this assembly and then after that there is a long slip unit that the long drive shaft is connected to with a u-joint, then back to the rear end. My "swing" bearing is a rubber thing encased roller bearing that is pressed over the shaft that comes in a bracket that bolts to a cross member under there. That thing?

Yeah, that's what was vibrating and about to fall apart. The rubber and the bearing had disintegrated and was making a lot of racket under the truck. The guy at the repair shop said, "How the hell did you drive it like that? When we unbolted the bracket from the cross member it all fell onto the floor!"

I have thought about the trans output shaft bearing but it "seems ok" as far a freeplay, but that isn't going by any spec it is just going by movement with my hand, but there some movement. Vibration is in no way in the steering wheel. It's felt in the floor board. It's not tire balance vibration. In the almost 3 years I've had the truck the vibration has been then, I'm not sure if it has progressed some over time. I think going to a slightly wider tire has made it more noticeable though. In the sweet spot when the vibration is at it's worst, which seems to be right around 40mph in 3rd, yes you'd see ripples in a glass of water I think. But I do not make it a habit of driving with an open container. At other slower speeds it's noticeable, and at higher but gets much less noticeable.

I have heard the carrier bearing called a swing bearing, but only very rarely. So yes, same thing. Mines new as are my U-joints which made zero change to the vibration. I don't "think" it's the transmission output bearing, and it does not "seem" to me to be excessively loose, and is not leaking any fluid. I don't "think" it's the pinion as it is not loose, and leaks no fluid, but I have been told a bad enough pinion can make vibration, I don't think that applies to me. I do have the semi-float 14B and have not checked the axles for being bent, but this does not feel like any bent axle I've ever felt before. I'm yet to check for a bent driveshaft, but will. I'm open to being told I'm wrong to be writing off any of the parts I think are not causing it.