I hope someone may have some ideas on a problem I am having in my driveline.The deal is when I drive my 65 Lark upwards of 60 MPH I start to get a vibration from somewhere.It is not in the engine or the steering or tires for sure.If I take off right after starting the car and hit the highway right away there is no vibration at all even up to 80 MPH but once I go about three miles and the car gets warmed up it starts to vibrate.When I let off the pedal say going around 60 the vibration quits when I release the pedal.I have a 4 speed Muncie for the trans.Any ideas I could check out would be appreciated.Oh I tried 3 different 65 driveshaft I have and they all act the same way.I am thinking maybe a rearend bearing starts thus when it gets hotter or maybe a bearing in the trans but I just do not know for sure.Thanks.
any bearing noise, maybe a rear bearing but i cant really see that causing vibration. and you tried different set of tires? maybe trans bearing?trans mount bad?where do you feel vibration? what condition is harmonic balancer? need a little more info,
Make sure the trans is in the proper location. If any of your moount bushings are worn, the trans could be cocked over to one side.
The location of the vibration seems to me to be more in the rear of the driveline and car.The trans mount may be something to look at but I did put in a new one about 8 months ago when I had the trans out.Its not the tires I am sure.As stated in the original post I can take off from my house and go about two blocks over to the pavement and head right up to a cruising speed of 80 and its perfectly smooth until I go about 4 or 5 miles then it starts to vibrate again,that is the part that has me so baffled.It almost has to have something to do with a problem only when things are warmed up.I have checked my rearend and trans grease and both are fine.I have tried 3 different driveshafts but this seems unlikely it would be that anyway seeing that this only happens when the car is warmed up good.Anywhere up to about 55 warm or cold it is smooth.When I approach atleast 60 when the car is warmed up it starts to do it...........Thanks.
Oh how do you check the condition of the yoke input bearing in the rearend,I think that may be the culprit and how hard is to pull the yoke and change this bearing?
Doubt it's the small pinion bearing, but the pinion could easily be loose. If venicle was mine, I'd jack the car up, set vehicle on good jackstands, drop the rear of the driveshaft, then with a gloved hands grab hold of the pinion flange (yoke) & agressively push & pull on the pinion flange. If you sense any to-fro motion on the flange & attached pinion, the pinion is loose. When pinion is loose, besides a clunking, & possible vibration, an abnormal wear pattern on the ring & pinion is introduced. Ck this, then post back. If pinion is loose, I will post back. Got Posi? :3gears: Roger
I had the same problem with my truck but it was in first gear. Had the driveshaft ballanced and it never vibrated again. Was a cheap fix too only like $15.
Well I pulled the driveshaft and checked for any in and out and up and down play and there appears to be no looseness.I did change to another driveshaft and this could be the problem as the different one seems to have helped.I have 3 65 driveshafts from different Skylarks and I guess I could try them all and see if any will get rid of this problem.I have a question about the balancing of driveshafts if someone knows.Is there a differance between manual and auotomatic driveshafts?And if I would have one balanced and give this a try how do they know how to balance a particuliar shaft to your car?Would it be likely that I would have 3 65 Lark driveshafts that would be out of balance for my car including the original which seems to produce the most vibration.The vibration definitly is in the rear of the car as I had my wife ride in the trunk to check it out,just kidding but i did remove the rear seat and had her drive while I sat in back and checked it out and its definitlety not coming from the trans or engine.Thanks for all your help and I hope I can figure this out its driving me crazy.................Bruce.
Forgot something,I have read somewhere that when you remove a driveshaft you should mark it and put the shaft back on the same way it came off but I am past that point as if this is true I do not know how it goes on now correctly.I assume you could only have it on 90 degrees off so turning it once would take care of it if that was the problem.If I have it balanced how will I know which way to put it back on?
I had an old timer show me some thing about drive shafts several yrs ago. He said that 'If a driveshaft is straight it doesnt have to be balanced'. Then he proceeded to knock the balance weights off my drive shaft and then chuck it up in a lathe and straighten it. No viberation. Also take a hard look at the slip yolk, they do wear out.
I haven't tried this, but I once heard you can add a balance weight to a drive shaft by using a worm-gear hose clamp.....the screw acts as the weight. Maybe you could try this in 4 different locations to see what effect it has. Also if the pinion angles were off, it could produce a vibration at speed. MSC66 started a thread on the subject recently with some good info. I'll try to find it.
The slick way to do it is to use two clamps right next to each other, so you can effectively "remove" weight if necessary by rotating them away from each other an equal amount at the point the weight is needed. The '67 Buick service manual actually specifies a procedure for this. Devon
That would be my first thought---had a Chevy S10 with same symptoms---once it was balanced it was fine. Just my 2cents. Pete
I will try to find someone here local that balances driveshafts.I am not in a real big town but hopefully someone here does it and I will try to have it balanced and put in new u- joints and see what happens.If that does not work I guess I have another rearend but I hope it does not come to that and that is the problem.Thanks.
I went through hell with a driveshaft vibration and learned a few things. Denny from Denny's Drive Shafts told me this..... Jack the rear of the car and put jack stands under the rear axle. Remove the rear tires and put the lug nuts back on to hold the drums. Start the engine and put the trans in the gear that makes the vibration and then adjust the idle screw on the carb to the RPM and speed you get the vibration. Then crawl under the car while it's running (and vibrating) and look around. Mine was coming from the front of the driveshaft and it was obvious by eye and ear.
