1959 Driveshaft

La Hot Rods

Well Known Member
Supporting Member 1
#61
If you can make it vibrate on the jack stands then take a hose clamp and a 1/2 ounce wheel weight and start moving it around different places on the drive shaft.
Now just do this at the ends near the u joints. See if you can make it worst or better by rotating the weight around or moving it from one u joint to another.

Do you have large heavy washers at the center support mount? May be flexing if not clamped well.
 

1959chevybr

Well Known Member
#62
Good morning here from Virginia Beach! I will do exactly as you suggest on the hose clamp. When I am under the car with it lower speeds say 40, I can feel the trans, axle, CB mount and pinion and there really does not seem to be much vibration anywhere. Drive shaft is smooth as silk. Then go to 60 and everything has some vibration but I don't know what to compare it to, how much for example a perfect car would have. Still at 60 the drive shaft feels smooth and the axle, the most I feel is coming off the front of the pinion housing. I will try a hose clamp today. I do have strong 1 1/4 diameter washers under the CB. One thing that bothers me a lot and I can not decide why this is so, sometime far back I had to elongate the holes slightly to the rear for the CB (this is true for 3 drive shafts and 3 CB). We have checked every bushing and every bolt on the rear and nothing shows any issue but thought worth mentioning. Thanks for the comments.
 

425/409ER

Well Known Member
#63
I can feel for you buddy, I went through all this kind of vibration crap last year when I put the 409 in the car for the 1st. time in years. I did have a lot of vibration trouble when the SBC was in it also but was way worse with the 409, don't know why. I farted around with the driveshaft several times only to tear out a hanger (1st. one in 30 years) changed angles and u-joints all the usual suspects, no change, nada, nothing. I got fed up after the big car show here in MN. then tore out the crappy 2 piece hanger crap and put in a 1 piece driveshaft. OH BOY, what a change, just like driving my old Chevelle back in the day. Now, I know this is not for everyone as you do have to modify the frame a little, but if the car is not some collector car then I say go for it. That is what Hot Rodding is all about.
 

1959chevybr

Well Known Member
#64
Guys thanks for all the suggestions.. Someone asked for pictures of the underside of the car meaning the setup. Kinda hard to show much when its all black but here goes.
 

1959chevybr

Well Known Member
#65
425/409
thanks for your comments.. Success stories are what I am looking for. The fabrication is no problem I just hate to do it and still be the same, seems your experience would lead me to believe its worth the effort. Can you give me a few details about your mod? Drive shaft size, how much did you cut from the bottom, trouble getting driveshaft in and out? What u joints? Any road blocks you experienced? Did you have to do much E brake cable fab?Thanks in advance..
 
#66
Hello.Lets go back to wheel spacer.Is it just one of those universal type spacers? with elongated holes? if it is you have to find a way to hold spacer some what centered.I use a small piece of masking tape doubled over.If its not that how about Harmonic balancer?
 

1959chevybr

Well Known Member
#67
They were bolt on spacers, 1 inch. They are gone as the wheels were close but not hitting so we eliminated them. As far as the harmonic balancer and all engine vibrations, we tried eliminating that by running 62MPH and actually shutting off the engine. The vibration remained until we coasted under 58 MPH, we feel we eliminated the engine/trans as being the culprit. Thanks for you comments and thoughts because I have got to start thinking out of the box, we have done most all things trouble shooting wise, just not the right thing yet.
 

IMBVSUR?

Well Known Member
Supporting Member 2
#68
I am curious about something. If possible, can you tell us, When the vibration occurs and you shift into neutral, where doesn't the vibration feel like it coming from? Under your seat, at your feet, or behind you?
 

1959chevybr

Well Known Member
#69
If am at a slow roll and punch it slightly it has a fairly heavy shutter. Then at 58 MPH it starts vibrating. It is fairly bad until after 65 MPH. The vibration is felt mostly in the seat and towards the rear. It does it in gear or in neutral or even with the engine off as long as between 58-65 and I might add on the gas or off. Thanks for your thoughts..
 

blkblk63ss

Well Known Member
Supporting Member 5
#70
Try this , have front drive shaft section about straight out from trans. Set the rear pinion slightly down. Then tell us if it is worse or better. What can it hurt just saying. Is it about stock height with this suggestion???
 

La Hot Rods

Well Known Member
Supporting Member 1
#71
Have you tried holding the brakes on while you run it on jack stands.
You should be able to torque it up and let a wheel start to move and recreate your thumping when start moving.
Just do this in a safe manor.
Set up a video camera to record what is going on or have a competent drive in the car then take a peek at a safe distance.
 

1959chevybr

Well Known Member
#73
Good morning everyone, I am at the Myrtle Beach Run to the Sun car show but with no car unfortunately. Ok I am going to try to respond to all three posts above in one reply. We have tried the drive shaft coming straight in line with the tail shaft, from there we have added shims from none at all, all way thru as many as the bolt length on the banana link will accommodate, no change at all which is crazy, I think it at least should get worse but it does not, stays exactly the same that's why I am wondering if I am in the wrong ballpark. The suggestion of adding 100 pounds I can easily do as soon as I get home. The suggestion of holding the brake and trying to duplicate the shutter we have tried to do without success. The 60 MPH vibration is easy to duplicate but can not really tell where it is originating. I have put my hands on everything while it was going 60 and nothing definitive. You can still feel it in the seat while doing this but I have sat under the car at 60 and basically learned nothing. The shutter is different we do not seem to be able to duplicate that on the lift. Holding the brake, from dead stop to a slow roll then hit the gas it just does not duplicate. In my earlier post I stated this but I will reiterate for clarity, I have had 3 drives shafts balanced and installed including the slip joint with poly CB, it was worst of all. I made a lower CB, no help. We have set all angles to the limits of the adjustment. On everything done, I have not changed the issue by more than one point on a scale of 1 -10. We have put on 4 sets of different tires and I have tried every idea suggested in this thread and will continue to do so because someone will suggest something I have not tried and it will be fixed. I hope no one thinks I am blowing off their suggestion because I take every one seriously. Some I have just done 10 times and some others I have never even thought of. Its a nice car that I cant drive, very frustrating . I am considering a one piece drive shaft and have read every thread on this site but only a very few state their success on this, I would like to hear more, fabrication roadblocks, drive shaft size and especially about results, good or bad. How good or bad? I have spent a ton of money on just this one vibration issue, 3 drive shafts, balancing, several new sets of u joints, two drive line shops evaluating the issue, etc. I need all the help I can get and appreciate everyone's effort. I did buy a new on car adjustable banana link and will install that on my return, the only advantage there is a slight more amount of adjustability. thanks guys..
 

dm62409

Well Known Member
Supporting Member 10
#74
Just a thought here, have you checked the balance of the brake drums? Some are quite far out of balance.
 

wristpin

Well Known Member
#78
LA Rods aka James would know the answer to this alot better than i would...could the vibration be caused by transmission internals out of balance once it's internally in drive selection?
 

blkblk63ss

Well Known Member
Supporting Member 5
#79
I did a search on u tube google and they are saying there are some thing's to watch for when mating different engine to 4l60 transmission. Flexplate mating, wrong flexplate ect. They call it a engine trans bucking I know you say it dont vibrate with engine rpm up by it self ,but you are not spinning driveshaft when you do that.Sound's like a imbalance in that area. You might want to do a google search on that.