need advise: driveshaft problems i think

[project 67 sub]

ok so i took my driveshaft down to a driveline shop yesterday(the 16th) that builds custom & high performance driveshafts(they have been their a while and heard they do good work). took it down because mine had a wobble while driving. well after i got it back he said that every thing is good to go now but it was pretty bad before he started(he had to fix the splined nub on the end cuz it wasnt welded on strait), drove it for a while like that but not on the freeway. it now has a new carrier bearing and fairly new u-joints still. but here is my question and problem: when i drive it on the freeway it feels like it is vibrating pretty bad and i dont know why because i just had it fixed, is their anything else that i can check that can cause this?
any help at all would be very much appreciated

[El Jay]

Go back to the drive line shop.

With a 2 piece drive shaft, the front & rear drive shafts could be "out of phase" if you separated them to take the drive shaft home.

Have him/them get everything balanced and then index the front/rear shafts so you know how they go together, when you get it back home to the truck.

I hope that made sense, if not, PM me or add to your thread.

[project 67 sub]

i had him take it apart and put it back together. the rear shaft is a new slip joint style i bought from cpp a while back.>>>http://www.classicperform.com/Store/...ruck/CPSSD.htm

[El Jay]

Oooops.

I freely admit that you have surpassed the scope of my knowledge.
But I would really like to know how you solve the problem

[project 67 sub]

hahah no problem bro. I would really like to know how to solve the problem as well and if i find out i will let you know

[El Jay]

I would truly appreciate that.

[project 67 sub]

are you having the same problems to or someting simular

[El Jay]

No.

But when it comes to things like "our trucks" I just like to have as much knowledge as I can gather crammed into my little pea sized brain.

Hope that made sense to you.

[project 67 sub]

oh yeah it made sense cuz im the same way. lol.

[see ten]

Have you already ruled out a bad tire/wheel/shock? They're all things that coud cause a vibration at one speed but not another.

[my67chevytruck]

Originally Posted by see ten

have you already ruled out a bad tire/wheel/shock? They're all things that coud cause a vibration at one speed but not another.

x 2 ! , I have also had slightly bent/warped axles cause vibrations as well....

[PanelDeland]

I would say take it to the driveline shop and let him drive it.He's the pro(expert is a different animal).He should be able to tell you what is going on.
When I'm stumped I always go to the pros,usually the ones on this BB but drivelines are kind of like carbs.They seem like black magic to those of us who do not know.

[sick69]

Something to think about,,,


If the yolk was not on the ds straight and you drove it that way for and extended period of time it could have caused damage to the pinon bearing. If the ds was bad enough just that wobble could cause pinon bearing damage aswell.


I would take it back to the shop for them to drive and check out on the truck. Hopefully it will be something simple and they can take care of it while you wait.


Just a thought,
Frank

[acl]

If and when you rule out the driveline, and if you still have an issue, check your flywheel/flexplate. Have you had this problem for a while? Have you changed fly/flex? I fought this same problem for sometime doing just what you are doing, replace this, balance that, and some smart bguy on this board suggested the flywheel and it looked fine but changing it took care of my problem. Good Luck. Gary

[brad_man_72]

we ballanced a shaft for a guy 3x, turned out that his pinion yoke was very offcast (a lot of its mas was off to the side).

after working in a driveline shop i realize that theirs alot more to making a driveshaft work other than just making it fit.

it never hurts to double check things like are all of the ujoint keepers in properly, is the rear joint centered in the pinion yoke, and signs of hitting anything with the driveshaft.

take te truck back to the same shop you had it ballanced at. a reputable shop should check the ballance for free, if theirs no signs of damage. guys that see this stuff everyday know what to look for.

[cdowns]

a couple of overlooked things are trailing arm bushings and panhard bushings as well as pinion angles if truck is raised or lowered. rearend bearings too

[bbarooo]

I just dealt with this issue and the culprit in my situation was a worn pinion yoke. The u-joint had just a tiny bit of play side to side. Only noticed at speeds above 60mph.

Does the vibration occur in nuetral as well?

[project 67 sub]

Originally Posted by see ten

Have you already ruled out a bad tire/wheel/shock? They're all things that coud cause a vibration at one speed but not another.

all the shocks are still fairly new and the tires are not that old as well. the vibration that i have i dont feel it in the steering or anyting but i feel it through the floor boards all the way up into the seat

[project 67 sub]

Originally Posted by acl

If and when you rule out the driveline, and if you still have an issue, check your flywheel/flexplate. Have you had this problem for a while? Have you changed fly/flex? I fought this same problem for sometime doing just what you are doing, replace this, balance that, and some smart bguy on this board suggested the flywheel and it looked fine but changing it took care of my problem. Good Luck. Gary

no i never had this problem until i sheared the splined nub off the front driveshaft, and had another one welded on buy a buddy. i eyeballed the hell out of it to get it as strait as possible for a temporary fix but never drove it on the freeway, and only at lower speeds of about 40 were it didnt vibrate to bad. the flywheel should be fine because when i changed the trans a while back it was fine

[project 67 sub]

Originally Posted by bbarooo

I just dealt with this issue and the culprit in my situation was a worn pinion yoke. The u-joint had just a tiny bit of play side to side. Only noticed at speeds above 60mph.

Does the vibration occur in nuetral as well?

only at about freeway speeds (its pretty bad)

[acl]

Originally Posted by project 67 sub

no i never had this problem until i sheared the splined nub off the front driveshaft, and had another one welded on buy a buddy. i eyeballed the hell out of it to get it as strait as possible for a temporary fix but never drove it on the freeway, and only at lower speeds of about 40 were it didnt vibrate to bad. the flywheel should be fine because when i changed the trans a while back it was fine

If this just started since your driveline break I agree it should not be the fly/flex plate. Who knows. You mention above that you "eyeballed the hell out of it to get straight as possible" if you are talking your driveline from rearend to transmission, that might be your problem. Your driveline should not be straight. I not sure of the actual number but plus or minus 3 degree comes to mind. It has been mentioned a couple times before about pinion angle i would check that. If thats not the "straight" you are refering too let us know. I am not the smartest by any means and correct me if i am wrong, but i believe if your driveline is straight with no pinion angle, it could be a factor. Gary

[project 67 sub]

Originally Posted by acl

If this just started since your driveline break I agree it should not be the fly/flex plate. Who knows. You mention above that you "eyeballed the hell out of it to get straight as possible" if you are talking your driveline from rearend to transmission, that might be your problem. Your driveline should not be straight. I not sure of the actual number but plus or minus 3 degree comes to mind. It has been mentioned a couple times before about pinion angle i would check that. If thats not the "straight" you are refering too let us know. I am not the smartest by any means and correct me if i am wrong, but i believe if your driveline is straight with no pinion angle, it could be a factor. Gary

have a 2 piece driveshaft. when the front half broke time i eyeballed the hell out of the splined nub on the end of the driveshaft to make sure it was as strait as possible by eye and welded it up for a temporary fix. my rear half is not striat and level that i know of. i dont know what the pinion angle is at but the rear end is lowered with 2" drop springs and 3" blocks

[project 67 sub]

think i might have found the problem(almost positive) but not sure. would the front u-joint bye the trans yoke cause it if it has a little side to side play, and should the yoke have any play in it itself? any help at all is greatly appreciated, cuz im trying to make it more reliable and get it ready for a carshow coming up on the 14th

[brad_man_72]

sorry i lol'd at eyeballed the hell out of it. even if the shaft was perfectly straight, (we dont let car driveshafts exceed .002" on the stub) the one from the factory wasnt, and it was ballanced to compensate for the runout from the factory. so no matter what you do it will vibrate.

so are your yokes/u-joints in time? that can also cause a vibration.

the only way the shaft will ever be right is to take it to a pro have them straghten it if they can, and ballance both pieces together, mark the way they were ballanced and put them back in the truck using the marks.

im not pickin on you, i do this every day and their is no way i could build a decent driveshaft without the specalized tools.

[brad_man_72]

u-joints should never have any play in them!!! well the crap that precision makes has about .030 endplay when new....
trans yoke will have a little play.

make sure the keepers are in the ujoints properly.