Driveline vibration

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Warren

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Hello,
On my 1974 Hang 10 I have been restoring I finally got it to a condition to drive on the highway. I has a cyclic vibration which is the worst at 45 MPH (bucket seat starts to shake). Putting it on rear jackstands, removing the rear tires, bolting on the brake drums, and then running up and down the speed range no improvement. Swapped driveshaft rotation 180 degrees no improvement. Removed driveshaft and had checked out for balance by a shop and it and U-joints are ok. Started investigating the automatic transmission rear bushing/bearing (as discussed elsewhere on forum) and maybe this is where the problem is. With the driveshaft still removed, I can move the rear output shaft at least 1/32" radially. So my question is, how much play should I have and maybe the rear ball bearing is the problem?

Thanks for your thoughts.
Warren
 
Warren said:
Hello,
On my 1974 Hang 10 I have been restoring I finally got it to a condition to drive on the highway. I has a cyclic vibration which is the worst at 45 MPH (bucket seat starts to shake). Putting it on rear jackstands, removing the rear tires, bolting on the brake drums, and then running up and down the speed range no improvement. Swapped driveshaft rotation 180 degrees no improvement. Removed driveshaft and had checked out for balance by a shop and it and U-joints are ok. Started investigating the automatic transmission rear bushing/bearing (as discussed elsewhere on forum) and maybe this is where the problem is. With the driveshaft still removed, I can move the rear output shaft at least 1/32" radially. So my question is, how much play should I have and maybe the rear ball bearing is the problem?

Thanks for your thoughts.
Warren
Click to expand...

I noticed you didn't say that you checked the tires....are they in good shape, not worn and balanced?
 
Warren said:
Hello,
On my 1974 Hang 10 I have been restoring I finally got it to a condition to drive on the highway. I has a cyclic vibration which is the worst at 45 MPH (bucket seat starts to shake). Putting it on rear jackstands, removing the rear tires, bolting on the brake drums, and then running up and down the speed range no improvement. Swapped driveshaft rotation 180 degrees no improvement. Removed driveshaft and had checked out for balance by a shop and it and U-joints are ok. Started investigating the automatic transmission rear bushing/bearing (as discussed elsewhere on forum) and maybe this is where the problem is. With the driveshaft still removed, I can move the rear output shaft at least 1/32" radially. So my question is, how much play should I have and maybe the rear ball bearing is the problem?

Thanks for your thoughts.
Warren
Click to expand...


1. be more specific on the issues, exactly when does it start, does it get worse or a little better faster, or does it go away at 55/60 and maybe return at 80 or not at all...
Does it do it at those speeds and if you pop it into neutral does it stay constant or get somewhat better....

2. the shop checked it for balance how? did they look at it? did they put it in a lathe? did they actually balance it? do they even have a balancing machine (you would be surprised at how many supposed driveline shops have none)

3. the vibration starts at 45 mph and you have what rear gear ratio ? did you recently go from 2.76 to 4.88 ?

4. with the shaft removed and you moving the out put shaft is a waste of time since the slip yoke is the ground hub surface in which supports the tail shaft in the housing on its bushing....

answer 1 thru 3
 
I am fighting the same issue. I had it last year. My fan broke and I figured I had a fractured fan causing an imbalance. Nope. This year I put in a new motor and tranny and had yet another driveshaft built. It's better but still there. I checked the balance on the rear tires and they were way off. I replaced the tires and the vibration is 70% gone, but the cyclic rotational noise is still there, faintly. The only thing not new is my Dana, and it has maybe 3000 miles on it. I think it's a rear pinion issue and am going to take it apart and use white lithium on the gears and see how it rides gear to gear. I feel your pain. It is driving me nuts. Just a light thrum - thrum - thrum noise and feel.
 
Run it up to 45-50 where it's doing it, take it out of gear and coast in neutral. If it's still there the problem most likely is aft of the trans. If it goes away, problem is with the transmission.
 
My motor, tranny, engine and tranny mounts, drive shaft, and rear tires are new. I am thinking pinion bearing wear even though I have maybe 3000 miles on my Dana 60. I'll have to tear it down to check, but I have to do something.

This is not my thread, but I share the same problem. I don't mean to hijack your thread, Warren. If one of us figures this out it is bound to help the other.
 
Mopar to ya said:
I had mine built by Proven Force here in town. When I hit the highway and put it in neutral it is still there.
Click to expand...


OK just because the shaft is new that doesn't mean that the balance was done perfectly and it could need to be rechecked...

Here is why, if they built the shaft and immediately balanced it while hot from assembly there is a 20% chance when it cooled (all round tube no matter what moves) that it is now out of balance (trust me i have done it and it changes).

The other issue is this, many shops use a dynamic machine, problem with the dynamic machines are they spin at 500 rpm and guesstimate where weight needs to be in a 3000 rpm scenario.

Something you are exceeding, if the rear hasn't grenaded or the pinion yoke isn't literally about to fall off it isn't going to make a issue.

You should have them re balance it and it's going to probably take a little weight

.
 
I was going to have it rechecked anyway. This is the third drives haft with different motor / tranny / rear end combinations, and they have all had this thrum - thrum feel to some degree. I don't think it's the drive shaft but I want to eliminate that as a possible cause. Plus it's under warranty and it will be free!
 
Warren said:
Hello,
On my 1974 Hang 10 I have been restoring I finally got it to a condition to drive on the highway. I has a cyclic vibration which is the worst at 45 MPH (bucket seat starts to shake). Putting it on rear jackstands, removing the rear tires, bolting on the brake drums, and then running up and down the speed range no improvement. Swapped driveshaft rotation 180 degrees no improvement. Removed driveshaft and had checked out for balance by a shop and it and U-joints are ok. Started investigating the automatic transmission rear bushing/bearing (as discussed elsewhere on forum) and maybe this is where the problem is. With the driveshaft still removed, I can move the rear output shaft at least 1/32" radially. So my question is, how much play should I have and maybe the rear ball bearing is the problem?

Thanks for your thoughts.
Warren
Click to expand...

I had the same problem on my Dart Sport......drove me NUTS.....it was the tailshaft bushing......I had the shaft polished, put a new bushing in, and VOILA. Could be a LOT of things though. This was my experience after doing a new driveshaft.
 
pastortom1 said:
I had the same problem on my Dart Sport......drove me NUTS.....it was the tailshaft bushing......I had the shaft polished, put a new bushing in, and VOILA. Could be a LOT of things though. This was my experience after doing a new driveshaft.
Click to expand...

Two different trannys for me, and one brand new. Not that it couldn't be it, so I will check that as well when I take the driveshaft out to get it rebalanced.
 
Mopar to ya said:
I was going to have it rechecked anyway. This is the third drives haft with different motor / tranny / rear end combinations, and they have all had this thrum - thrum feel to some degree. I don't think it's the drive shaft but I want to eliminate that as a possible cause. Plus it's under warranty and it will be free!
Click to expand...


This sounds so familiar, find out what machine they use to balance it. . .

Sounds like the problem is all in the balancing
 
@Mopar to ya: If you have a 200r4 tranny in your car (assuming from your details in sig) obviously you have some kind of custom tranny mount, have you ever checked to see if the motor and tranny are mounted square in the frame? The motor and tranny could be in crooked which would cause vibration.
 
Proven force can only balance a drive shaft to 30 mph,ask me how i know.My car also has a vibration at higher rpm.We use them for work and we found out on a 300zx drive shaft,same problem.
Have not found a place to balance yet.I was going to try AA driveline in Anoka.
 
BRONZEBEE said:
Proven force can only balance a drive shaft to 30 mph,ask me how i know.My car also has a vibration at higher rpm.We use them for work and we found out on a 300zx drive shaft,same problem.
Have not found a place to balance yet.I was going to try AA driveline in Anoka.
Click to expand...


They are using one of the dynamic machines, thats a big problem.


Try some other shops and ask which machine they use
 
I have Proven Force checking the balance on Thursday, and an appointment at ADL to check my Dana on Monday. I am tired of the vibration and it is getting fixed.

About the 200R4, it is very square and very straight. That was a major concern as we settled everything in. I have shims to raise and lower the transmission and have tried it both ways. The main thing is that it was there with the 319/904/Dana as well.
 
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