joe c Posted April 11, 2020 Share Posted April 11, 2020 In the car right now is the original dshaft it has been completely rebuilt and balanced. I do have another dshaft which I bought and installed in the car and is in good condition thinking my original one was defective but I get the same results with either shaft this is why I tried axle bearings. Link to comment Share on other sites More sharing options...
EmTee Posted April 11, 2020 Share Posted April 11, 2020 Have you tried swapping wheels & tires front --> rear? If the vibration moves from the seat of your pants to the steering wheel that would imply a bad wheel or tire. Link to comment Share on other sites More sharing options...
joe c Posted April 11, 2020 Share Posted April 11, 2020 I don’t believe I’ve switched wheels front to back yet...although I had crossed my mind it just doesn’t seem to be that kind of vibration but you never know I’m open to anything. I’m going out to do that now then road test again 1 Link to comment Share on other sites More sharing options...
RivNut Posted April 11, 2020 Share Posted April 11, 2020 Problems are not necessarily where you think you're feeling them. A friend of mine thought he had a problem in the rear end of his van. I'd drove and he climbed around in the back trying to get close. Turned out he had a bad front wheel bearing. Sounds travel in weird ways through metal. Link to comment Share on other sites More sharing options...
joe c Posted April 11, 2020 Share Posted April 11, 2020 No difference with the tire swap 1 Link to comment Share on other sites More sharing options...
joe c Posted April 11, 2020 Share Posted April 11, 2020 Yes I totally agree but this seems to be coming from the back of the car and feeling it through the back of the front seats and through the console Link to comment Share on other sites More sharing options...
RockinRiviDad Posted April 11, 2020 Share Posted April 11, 2020 I am in the middle of the same $#!+ storm you’re in. I can’t find where my vibration is coming from either. But my car is lowered One idea I was given by a mechanic friend was to get rear end up on jack stands. Then start the car, put it in gear, run it & check rear wheels while spinning. U might find a wobble which could be a bent axle, bent wheel or lopsided tire Link to comment Share on other sites More sharing options...
joe c Posted April 11, 2020 Share Posted April 11, 2020 Ive done this, my buddy has a shop and hoist and I practically live there with this car trying to figure this out Link to comment Share on other sites More sharing options...
RockinRiviDad Posted April 11, 2020 Share Posted April 11, 2020 I had a worn transmission tail shaft bushing. Mine was worn so bad that my dshaft had a lot of slop/play. That is located at the end of transmission, right where the dshaft goes into trans. I thought fixing this would fix my vibe…NOPE. It didn’t. But check yours. Maybe it’ll help your situation 🤷🏻♂️ Link to comment Share on other sites More sharing options...
joe c Posted April 12, 2020 Share Posted April 12, 2020 Thanks...I’ll check that, I know I looked it last summer and I had the transmission rebuilt 2 years ago so you think they’d replace that in the rebuild. I’ve also had the car back to the transmission shop to help with this vibration issue you’d think they might have suggested that too Link to comment Share on other sites More sharing options...
XframeFX Posted April 12, 2020 Share Posted April 12, 2020 To define: With vibration there's excitation and resonance. There will always be residual imbalance for excitation, As long as the frequency does not coincide with the resonance. For resonance, something went sloppy structurally dropping the resonance frequency into the operating range. Trans mount, tail shaft bushing or centre support? So 2 paths for 3 sources of excitation. 1) Slip yoke of front shaft 2) rear of front shaft and 3) front of rear shaft. Number 1 & 3 are floating. If the vibration is always there and keep in mind imbalance increases with the square of speed (an extra variable to consider), then it's not resonance but something binding, a forced vibration. Knowing the frequency of vibration would be a BIG help in analyzing this. Propeller shaft frequency or, axle frequency? If it was a scored ring and pinion gear, you'd have a hum. With David, if the tailshaft bushing was worn, it could've been the result of vibration. So the front half of the propeller shaft to scrutinize. On a new install, a little tougher. I have a '64 prop shaft purchased as a core for a swap in my '63. I couldn't believe the swack of balance weights tacked on to both ends. Those should be weights for Trim Balancing and not 'Correction Weights'. Good Luck! John B. Link to comment Share on other sites More sharing options...
joe c Posted April 12, 2020 Share Posted April 12, 2020 Thanks John, great information to take in and review. When you mention about frequency of vibration do you mean how often it occurs or at a specific speed? A scored ring and pinion could be the problem as this is the only original part that hasn’t been rebuilt even though I had the rear end out and looked at by a rear end ”specialist“ although he just looked at it no detailed inspection and told me to put this back in the car...I’m focusing on this part of your explanation because of that. This vibration is similar to a wheel bearing hum but not constant as one sound it gets louder then quieter and continues in that pattern, then this is heard and felt from the rear of the car through the back of the front seats and console tunnel and seems to be more noticeable around 40-50 mph and higher mph too. I know that doesn’t completely eliminate the others you mentioned but the vibration hasn't really changed as I try the obvious fixes. I’ve had the dshaft rebuilt and balanced including new hanger and bearing, all u joints, both centering ball kits, new engine mounts, trans mount and inspection of fly wheel and harmonic balancer. I also bought a good used dshaft and tried that too with the same results. Thanks Joe Link to comment Share on other sites More sharing options...
EmTee Posted April 12, 2020 Share Posted April 12, 2020 Does the sound (or vibration) change when you apply, then lift-off the throttle (i.e., load/unload the rear end)? Does anything change when you put the trans in neutral and let the engine go to idle at 40-50 mph? What happens if you hold that speed in 2nd gear? Link to comment Share on other sites More sharing options...
joe c Posted April 12, 2020 Share Posted April 12, 2020 It’s noticeable under load or more when just holding at any speed. When I put the trans in neutral and coast it’s there too but not as much because of the decline in speed. Second gear has the same results. Link to comment Share on other sites More sharing options...
XframeFX Posted April 12, 2020 Share Posted April 12, 2020 Joe, what I meant on frequency is vibration frequency. Vibration usually consists of many frequencies. However, what you hear is usually the predominant frequency component. Good points to pin-point the possible sources mentioned above. Process of elimination is another method by replacing questionable parts, the design a 3rd. Another prop. shaft does the same? Now thinking what else? As Ed mentioned, the source could be from an entirely different location. The floor-pan could be the loudspeaker! Again, the frequency? Simply, a growl or rumble being a low frequency and a hum a high frequency. The ring & pinion will have a 'mesh frequency'. That is the number pinion teeth X pinion speed or, number of ring gear teeth X axle speed (same frequency). It will sound like a hum and materialize at a certain speed say, 55 mph and diminish when you let it coast taking it out of that critical speed quickly. If the ring and pinion are scored excessively, the hum will not be at a critical speed but always there. It's amplitude will increase with speed of course but will not be a critical speed behaviour. Even with analysis equipment, we grasp-at-straws and resort to a frequency analysis because we have no baseline data with acceptable vibration. What is an exceptable amplitude? So, we assume the predominant frequency the culprit regardless of amplitude. Again, 1) prop. shaft frequency 2) axle frequency and now, 3) gear mesh frequency should be considered. To separate differential ring & pinion from the side gears and the vibration is still evident with light load, a big empty parking lot making turns left and right. No special tools required but results to be taken with a grain of salt. If anyone has the differential 3rd member out, always count the number of ring gear and pinion teeth before assembling, just-in-case. Example: 42 ring gear teeth and 14 pinion teeth = 3.00 : 1 final drive ratio and a mesh frequency of 747 Hz. cruising at 3200 engine RPM in 3rd gear of course. Usually, such depth of analysis as above is seldom done because in the shop the problem is resolved by the change-out of parts. Oh, has the pinion seal ever been changed-out? If so, the pinion nut should've been marked before removal and torqued to just beyond that mark, not short of that mark. John B. Link to comment Share on other sites More sharing options...
joe c Posted April 12, 2020 Share Posted April 12, 2020 Hey John i’ll have this a few times to comprehend but I get you mean. In short the pinion/ bearing has never been touched so that’s why I keep looking there because of all the other parts I’ve replaced. Right now I’m at my buddy’s shop and on the hoist and just for experiment I drained the diff fluid and put in a full litre of Lucas then topped up with diff fluid to see if this dampens the vibration. Another test we did was drive the car up to 50-70 mph put it in neutral and shut down the engine and let it coast, and still felt the vibration but more towards the front rather then the rear of the front seats. Thanks Joe Link to comment Share on other sites More sharing options...
RockinRiviDad Posted April 12, 2020 Share Posted April 12, 2020 I am trying to follow along to learn. I hope to apply some of the knowledge posted to get rid of my vibration too. But…wow…u guys are super smart…my head is spinning haha…maybe its the virus making my head spin haha Link to comment Share on other sites More sharing options...
joe c Posted April 12, 2020 Share Posted April 12, 2020 I hope It takes my vibration away... haha Link to comment Share on other sites More sharing options...
joe c Posted April 12, 2020 Share Posted April 12, 2020 Ok I’m back home and after filling the rear diff with Lucas the vibration is still there but reduced in noise quite a bit.. I think I’m getting close to answer... 3rd member bearings. I don’t know of anyone in my area who does these. I think it’s easier just to get a used 3rd member with a 3.23 ratio non posi but wouldn’t mind a posi. Are the axles the same seeing I just put axle bearings on. Any thoughts? thanks Joe Link to comment Share on other sites More sharing options...
XframeFX Posted April 12, 2020 Share Posted April 12, 2020 Sorry for being so technical. I've dealt with this on a Fleet Chevy Van assigned to me decades ago. In a van, its like a noise chamber. The fleet auto shop Mechanic didn't like me bringing the Unit back with the same complaint. When asked about the gear wear pattern, "it's fine". I did my own analysis instrumenting the differential and axle with accelerometers and signals into a tape recorder. Data indicated the ring & pinion set. I outsourced the van to a driveline specialty shop where they replaced the Ring & pinion set. The old ring & pinion was visibly scored-up, no nice wear pattern. Oh, Drive shaft attaches with an open yoke like the '63 or, a flange like the '64 & 65? Why Lucas? Ripe bananas forced through the filler hole no good? LOL Link to comment Share on other sites More sharing options...
EmTee Posted April 13, 2020 Share Posted April 13, 2020 Yes, from your answers to my questions it does seem to be tied to vehicle/wheel speed, not engine RPM. Also, not torque sensitive (vibration both during acceleration and coasting). I'm also thinking rear end bearings. If you can locate a reasonably priced 3rd member that would be a fairly easy swap. Link to comment Share on other sites More sharing options...
joe c Posted April 13, 2020 Share Posted April 13, 2020 Yes absolutely it’s not difficult to swap the 3rd member out... trying to find one is tough especially because I’m in Ontario Canada and most parts are in the States. Keep it in mind if you know where to get one and pass it forward to me please. I appreciate you’re input and I’ll update on this thread when I change it out Thanks Joe Link to comment Share on other sites More sharing options...
joe c Posted April 13, 2020 Share Posted April 13, 2020 The Lucas was just a test to see if the vibration changed and it did so I think I’ll look for a 3rd member. The driveshaft attaches flange type 1965. Technical is good I understand it completely it might take some thinking on my part to sink in though... haha...I appreciate you’re input on this Thanks Joe Link to comment Share on other sites More sharing options...
RivNut Posted April 13, 2020 Share Posted April 13, 2020 Perhaps you could check the lash on the ring and pinion before opting for a replacement. Link to comment Share on other sites More sharing options...
joe c Posted April 13, 2020 Share Posted April 13, 2020 I hope to find someone local who can help me with this if I decide to repair rather than replace. I understand the process but I have never done this before, It’s described well in the service manual but with a lot of unique tools that I don’t have or ever used so I’d need help from a professional and describe in the manual as drive, coast and float noises seems to make sense in my situation, that’s why changing it out is easier and I could do that myself. I had the 3rd member out last year and he the rear end specialist checked the back lash and told me to put it right back in the car but no bearing check.. I wasn’t pleased because it was out I wanted the bearings changed, but went with his answer anyway and here I still am dealing with this vibration. Hopefully this will solve this issue if I can locate a good used 3rd member. Thanks Joe Link to comment Share on other sites More sharing options...
XframeFX Posted April 13, 2020 Share Posted April 13, 2020 Ah, a fellow Canadian. Should've said so, I would've given you the Gold package! Here's another thought. I purchased my drive shaft with the flange as my '63 has the open yoke. It might be a mute point since you installed a 2nd drive shaft (almost as big of an impact as knowing what frequency you're dealing with) but that flange should have 4 each 3/8"-16 bolts of equal mass (w/washers?). There's more . . . . 3 of the 4 3/8" holes in my flange are rusted-out. Not only do I have a core drive shaft assembly requiring a total rebuild but, it came with a core pinion flange! To remedy, could use longer 3/8" bolts with nuts on the backside of the flange or drill-out all 4 holes and thread for 7/16"-14 bolts. For a member spinning up to 5000 RPM (95 mph?), I prefer the latter done by a machine shop of course. You want to minimize spinning parts here. The 'more part', is that 7/16" bolts still fits through the drive shaft hole without having to drill that out. Makes me wonder how much slop there is with the 4 bolts loose? There appears to be no precise centering, a design issue? Those 4 bolts could be tightened with the drive shaft slightly off centre. This is root cause stuff. Some of the symptoms between you two might be damage yet to be discovered. ie, a pinion seal might have been replaced earlier in the Riviera's life and the nut not torqued properly. David might have a front drive shaft issue. My thoughts and mostly FYI stuff. Joe, PM me, the Dude that sold me the drive shaft might still have that 3rd member minus the pinion flange. Might be a posi? John B. Link to comment Share on other sites More sharing options...
joe c Posted April 13, 2020 Share Posted April 13, 2020 Hey John, nice to hear from a fellow Canadian...I’ll pm you right after I post my thoughts. My dshaft is stepped ”in”on the shaft end and that fits on the ”shoulder”of the pinion flange and both fit snug together, so no miss alignment is possible unless there’s a burr and you don’t get both sitting flat while bolting them together then you’d definitely have a wobble or vibration all my threads are in good shape and torqued to specs. You could be right someone could have done work on her before me I’m the third owner, but this was my brother in laws car since 1970 and he would know if any work like that has been done but good point to make, never know eh!! Thanks Joe Link to comment Share on other sites More sharing options...
joe c Posted April 13, 2020 Share Posted April 13, 2020 John I tried to pm you but said you can’t receive messages, I’m probably not doing it correctly can I message you through separate email? Joe Link to comment Share on other sites More sharing options...
KongaMan Posted April 13, 2020 Share Posted April 13, 2020 The thing with a used third member is you're rolling the dice. If you think it's in the rear end and you know the backlash, etc. in your current gears is good, it might be better to bite the bullet and change the pinion bearing* in what you have. I just went through that. Local shop wanted $800. I bought an in/lb torque wrench on eBay for $30, a 20-ton press from Harbor Freight for ~$120, and made a retaining arm to hold the yoke. Didn't take long at all, and now I own the tools. Which I have subsequently used to change axle bearings in two vehicles. Having said that, vibrations can be a bear to track down. It could be something like a vibrating exhaust pipe that gets amplified, a bad motor mount, an out-of-balance fan, or the way the jack is wedged against the body in trunk. Had another annoying vibration which turned out to be a bad idler pulley on a serpentine belt. You kind of go through the process: does it vary with vehicle speed or engine speed? Does it change with the gear you're in? Does it show up with the rear wheels off the ground? Etc., etc. Yeah, it's a PITA. * Pinion bearing noise will vary with vehicle speed, not engine speed. Mine kicked in ~30 mph. Dropped it into neutral and it was still there. Good luck. And bone up on your profanity. You're going to need it. Link to comment Share on other sites More sharing options...
joe c Posted April 13, 2020 Share Posted April 13, 2020 Hey KongaMan I definitely have those tools, I also want the side bearings changed too... might as well when your in there. Its overwhelming when you read the process in the service manual and all the specialty tools they used back in the day. If you look back through the pages of this forum you’ll read I’ve checked and verified everything you’ve mentioned, motor/ trans mounts, harmonic balancer, fan, exhaust system, Riviera rattle etc.. Its hard to simulate the vibration while on the hoist, I guess because of no load on the rear wheels. Your last point about pinion bearing noise is exactly the same thing happening to me, just kicking in at 40-50 mph even though I here it sooner than that. As described earlier to me and makes total sense, the floor resonates like a speaker and it probably likes this speed range to show up. Oh and I can swear just fine... my buddies shop who doesn’t swear at all makes it very tough at times...shucks...Haha Thanks for your input, Joe Link to comment Share on other sites More sharing options...
RivNut Posted April 13, 2020 Share Posted April 13, 2020 It could even be the infamous "Riviera rattle." Link to comment Share on other sites More sharing options...
telriv Posted April 13, 2020 Share Posted April 13, 2020 Joe, You can send the 3rd. member to JDRace in Ohio. He & I worked on him doing these center sections years ago. I informed him on the tools nec. to do the job & with some of my direction made some of his own. The average guy even with mechanical knowledge will have a hard time dealing with one of these 3rd. members. Jim has now done quite a few & I have sent people to him for work or call to ask questions. You may be miles ahead & know it's been done properly the 1st. time. Just my thoughts on the subject at hand. Tom T. Link to comment Share on other sites More sharing options...
joe c Posted April 13, 2020 Share Posted April 13, 2020 Good to know...I’ll look JD Race up Thanks, Joe Link to comment Share on other sites More sharing options...
joe c Posted June 23, 2021 Share Posted June 23, 2021 Okay guys...I'm back on this topic again, because of these times there has been a delay on the car but things are opening up again and I was finally able to get the car back to the mechanic's shop over the past three weeks. I previously re-read this thread and went through the car again to check on all the possibilities giving me the vibration, everything seems fine. I've found a new mechanic who has driven the car and has condemned the driveshaft. much to my disbelief i'm going to play it out and see what happens because i'm stumped on what to look for or do next. I have a spare untouched driveshaft that needs a little attention according to the mechanic, mainly a CV ball seat repair kit...does anyone know where I can get this from? I didn't think the CV kit is needed but again i'll play it out. One strange thing that has happened is about 6 weeks ago when I had the car out for a cruise and the vibration seemed to subside especially when accelerating from a stop light up to 40 mph and cruising at any speed below 40 mph the car runs nice and smooth but after 40 mph the vibration is back but is less noticeable. I've done nothing to the car as far as any repairs so i don't understand why this has smoothed out...any ideas? maybe live with it although it still makes me crazy... I have a used third member I found on line and have yet to swap it out with my original. its a posi with a 307 ratio and mine is a non posi with a 323 ratio not sure if this will help or not I welcome any advice Thanks, Joe C Link to comment Share on other sites More sharing options...
fxrspjc Posted June 24, 2021 Author Share Posted June 24, 2021 Make sure the Phasing is set correctly. Check your shop manual for the proper degree setting based on the year. If its set straight up that is a problem. Link to comment Share on other sites More sharing options...
joe c Posted June 25, 2021 Share Posted June 25, 2021 Definitely that would be a problem but the phasing is correct. I have the manual and have read this front to back on this chapter Link to comment Share on other sites More sharing options...
EmTee Posted June 27, 2021 Share Posted June 27, 2021 https://www.rockauto.com/en/catalog/buick,1968,riviera,7.0l+430cid+v8,1021420,drivetrain,universal+joint+ball+seat+kit,2396 Link to comment Share on other sites More sharing options...
joe c Posted March 8, 2022 Share Posted March 8, 2022 Hey Guys, I'll touch on this topic again for an update on my vibration. I've decided to take the engine out for a balance and refresh, as some of you may have known from my aluminum rad posting... The engine was completely rebuilt in 1986 but wasn't balanced. I probably have about 80,000 kms or about 50,000 miles, not much more kms if any... Anyway, with the engine apart and at the machine shop, the balancer, crank and flywheel on the balance machine is out 66 grams at the front and 117 grams at the rear. Hopefully this is my answer I've been looking for to solve this annoying vibration. The transmission is going to the shop who rebuilt it in 2016 just for a once over too. Before I took the engine out I removed the back half of the drive shaft to eliminate the rear end and ran the engine through the remaining drive train. Yes I still had the vibration. I'll keep this updated as I find out more info. Thanks Joe Link to comment Share on other sites More sharing options...
joe c Posted March 8, 2022 Share Posted March 8, 2022 I wanted to post the pictures of the crank on the balance machine. Thanks Joe Link to comment Share on other sites More sharing options...
telriv Posted March 8, 2022 Share Posted March 8, 2022 From the beginning thread it was stated this was a '63/401. From the pic of the crank on the balancing machine it appears to have a TH400 flexplate attached. Even tough the flexplate will bolt on six diff. ways, ONLY ONE is correct. Are the alignment holes in the crank & flexplate aligned??? IF NOT could be the reason the crank is so far out of balance. Just my observations. Tom T. Link to comment Share on other sites More sharing options...
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