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#1041248 - 07/08/16 04:23 PM Vibration from 65 mph and above  
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Posts: 104
Kawaiikeno Offline
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Kawaiikeno  Offline
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Vassar,Mi
I'm interested in hearing from people who have solved a vibration problem that starts around 65 mph and gets worse as speed increases.
I believe it began when we upgraded to an 8.5" Grand National rear end with a 4.10 gear set from a 7.5" 3.42 but it is very possible that doing so just lowered the speed at which the problem became noticeable.
Pinion angle has been changed a few times from 2.5 deg. down to 2.5 deg. up to match the motor/ trans. angle without making a difference.

Tires have been rebalanced and different rear tires have made no difference.
Drive shaft is a new strange unit with a 1350 u joint at the transmission and a conversion u joint in the rear all are spicer Hd. units. An original Grand National drive shaft was installed and made no difference.
Transmission is a performance 200-4r that was purchased a few years ago. There is a little bit of play in the rear bushing/yoke a new tail shaft bushing is the in the works.
About the only thing left is the transmission.
Any ideas would be greatly appreciated.
Thanks Mike


Daughter's 1984 Monte Carlo SS
Car Craft Magazine Humble Pie engine build
200-4r trans.
8.5" 4:10 Grand National rearend
[Linked Image]
#1041250 - 07/08/16 05:36 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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The PC Surgeon Offline
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The PC Surgeon  Offline
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Salisbury Mills, NY
Have you tried re-installing the drive shaft 180*?

Last edited by The PC Surgeon; 07/08/16 05:44 PM.
#1041251 - 07/08/16 05:50 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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AkronAero Offline
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AkronAero  Offline
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Akron OH
KK - you are not feeling vibration in the steering but in the chassis? You swapped shafts and rears so PCS's shaft rotation and your pending bushing replacement will hopefully resolve this.

A separating tire belt or other tire defect would also create problems even when newly balanced. You swapped rears, can you swap fronts? even one at a time?

#1041252 - 07/08/16 06:01 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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The PC Surgeon Offline
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The PC Surgeon  Offline
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Salisbury Mills, NY
Nissan Dealer once told me they do n to high speed balance the new tires I just purchased from them for my Armada. Took the car to mavis and had them perform the high speed balance and my 65 MPH vibration went away.

#1041257 - 07/08/16 07:42 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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Kawaiikeno Offline
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Kawaiikeno  Offline
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Vassar,Mi
Hi All
Thanks for the reply's I'll try and answer in order
We have tried installing both drive shafts and rotating them with no change.
The vibration is not felt in the steering as much as the drive line, all ball joints are new, tires have been load balanced the car was lifted with a floor jack tires and brake drums removed and spun up to 75mph with both drive shafts vibration did not change.
It's looking more and more like it's coming from the transmission. Previously I would have bet on pinion angle but yesterdays work proved that to not be the case.
Just a side note there were no rubber bushings installed on the cross member mounts at the frame I have some do and some don't
Thanks Mike


Daughter's 1984 Monte Carlo SS
Car Craft Magazine Humble Pie engine build
200-4r trans.
8.5" 4:10 Grand National rearend
[Linked Image]
#1041260 - 07/08/16 07:48 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
Joined: Nov 2012
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The PC Surgeon Offline
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The PC Surgeon  Offline
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Salisbury Mills, NY
Not to sound amateurish but when you measured the driveshaft, was the suspension fully loaded? If that yoke is bottoming out or to close to the end of the splined shaft, you will have these issues also. Maddening, isn't it? Don't ask how I know this......

Last edited by The PC Surgeon; 07/08/16 08:01 PM.
#1041263 - 07/08/16 09:44 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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Kawaiikeno Offline
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Kawaiikeno  Offline
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Vassar,Mi
Thanks but yes it was measured with full weight on the suspension for the new drive shaft, Strange has a sheet that you fill out. The factory drive shaft out of the donor Grand National was 3/8" longer. But like I said it hasn't made any difference changing back and forth and the only reason we bought a new one was rust on the old one.
Just to clarify when I say its a vibration it's not a little vibration there is no mistaking this for something minor it blurs the mirrors and can easily be felt in the seats,dash it will walk stuff off the console

And yes it is very maddening
Thanks
Mike


Daughter's 1984 Monte Carlo SS
Car Craft Magazine Humble Pie engine build
200-4r trans.
8.5" 4:10 Grand National rearend
[Linked Image]
#1041264 - 07/08/16 09:58 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
Joined: Nov 2012
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The PC Surgeon Offline
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The PC Surgeon  Offline
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Salisbury Mills, NY
Well, it sounds like you covered all the easy/minor/quick fix stuff. If the tranny had a bad tail bearing, it would certainly leak from all the vibration you described. Just to double check everything, you could mount a magnetic dial indicator and make certain all is round and true. Including the both yoke shoulders and the drive shaft at both ends. If all those check out, you may be right about the tranny. Check the axle flanges for trueness also with that dial indicator before you start tearing into the tranny. Hope it's something stupid!!!!!!!
My issue was the tranny yoke. Once I replaced it with a new one (This was from installing a Gear Vendors unit), my issue disappeared, but it took some time and detective work instead of just throwing parts at the problem.

#1041406 - 07/13/16 12:38 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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Beamer Offline
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Beamer  Offline
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Wyoming, MN
I for one can say that you can have a very worn out tailshaft bearing and still not have a leak.

I went thru this last year on my car - car is all stock with 40k miles, and all parts were original. No vibration until about 60-65, then it would start a high speed vibration in the chassis / floor. Nothing in the wheel.

Checked the driveshaft and the front and rear with dial indicator, all was fine within about .002" (within spec). Problem with this test is that it is not at speed. Gravity will do its thing and the slop will come out with the driveshaft at rest being rolled by hand.

Took my driveshaft to the first driveshaft shop to have it checked. Sold me u-joints and balance for $140. Came back with nuts, washers and spots of weld all over it. Still no improvement. Took the entire car back and left it for a week. Nuts, washers and welds are all ground off and new ones welded in different spots. Vibration still there however is reduced.

Took drive shaft to a second shop. They replaced the brand new sloppy U-Joints (Moog super duty) with factory Dana joints, replaced the Yoke the first shop had marred and damaged in a vice, ground off all the nuts, bolts and weld, found small "low spot" in the middle of the driveshaft that they heated with a torch (which took the low spot out - this was the original problem), gave me a tailshaft bushing and let me borrow a tailshaft bushing replacement tool since the car was not on site. Second trip cost me $225

Went back to first shop to ask for my money for the work done and for the money for the damaged yoke. Owner told me it was damaged when it got there (but they didn't want to sell me a new one?), and that balancing is a magical game that I would understand. I explained to him that I was a machinist / tool maker with 20 years experience, and that I worked selling capital machining equipment with 50,000RPM spindles and that I had a better understanding of balance than he could ever think about. I asked to see how he balanced driveshafts, and after a ton of arguing he finally showed me his LATHE. He did NOT have a balance machine, he just chucked the shaft in a lathe, checked it with an indicator and welded weight on wherever he felt it needed it *rolling eyes*. He still refused to pay me back.

Filed complaint with the BBB, logged a review on his Facebook page as low as possible. Put a stop payment on my check thru my bank (which even though it had cleared my account, was still withdrawn from his account and back to mine).

Unfortunately everything in the driveline doesn't need to be perfect, but it has to be in good shape. Unless the yoke, tailshaft bushing, U joints and driveshaft are in spec - you are just chasing a ghost. Have the driveshaft inspected and balanced. These services are really not that much money. Had I taken it to the 2nd shop the first time - I would have been out about $140. Find a reputable place that knows what they are doing and have the proper equipment (IE - a BALANCER - second shop balanced my driveshaft at 3000RPM, with is 2x as much as it will ever see in a car).

Michigan Truck & Spring in the Tri-Cities area does excellent work (i grew up in MI).

Place here was Proven Joint & Clutch in Ramsey, MN - they replaced the joints & yoke, fixed all the bad work, balanced it and even painted it like new in 45 minutes!

#1041411 - 07/13/16 04:26 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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Fred SS Online content
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Fred SS  Online Content
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Glassboro, NJ
Originally Posted By: Kawaiikeno
Hi All
. . . . Just a side note there were no rubber bushings installed on the cross member mounts at the frame I have some do and some don't
Thanks Mike


Monte Carlo SS do not have rubber bushings on the trans cross member at the frame. I wondered about this also, so I verified with the shop manual, no bushings for Monte Carlo SS.


87 SS, Harwood cowl induction hood, UMI trailing arms. Hooker 2050 Headers (Jet Hot Coated). Hooker Cat-Back Exhaust, Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, TCI 2400 stall converter, Denny's 3.5" Driveshaft, GBodyParts GNX Replica Wheels 18x8 & 18x9.
#1041587 - 07/17/16 11:33 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
Joined: Aug 2010
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Kawaiikeno Offline
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Kawaiikeno  Offline
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Vassar,Mi
Thanks Beamer and Fred SS I know her's didn't have the rubber bushing when she bought it but didn't know if it cane with one originally.
The only thing I haven't tried is the tail shaft bushing and swapping the 7.5 rear end back in.
In the very beginning we had problems with the new strange drive shaft with excessive play at the front yoke swapping the old rusted drive shaft back in and the vibration would go away. Thinking back before it started at 45-50 mph. never ran it up past 60-65. I ended up chucking a spare output in my lathe the new drive shaft maxed out my indicator where tho old one had Less than .030
they sent a different part and it checked good in the lathe.
I never did put an indicator on it in the car so I suppose the bushing could have been bad also, it only had 10,000 miles on the transmission since a rebuild so I figured it was good.
I called around to the local transmission shops asking if they could change the bushing in the car with no luck so far. Most tell me you just unbolt the tail housing and knock it out from the inside they don't realize the 200-4r doesn't have a removable tail housing.
So until I find either the tools to do it myself or a shop with the tools I'm at a standstill.
Thanks Mike


Daughter's 1984 Monte Carlo SS
Car Craft Magazine Humble Pie engine build
200-4r trans.
8.5" 4:10 Grand National rearend
[Linked Image]
#1041649 - 07/19/16 03:54 PM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
Joined: Apr 2009
Posts: 907
Fred SS Online content
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Fred SS  Online Content
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Glassboro, NJ
I replaced the tailshaft bushing in my 200-4r a few months ago, with the trans in the car. Fairly straightforward and easy job. I bought the tool on the web. I think it is made by Atec Trans. I'd be happy to loan it to you. PM me. I did post up some pics of me doing the job. I think I posted it in the driveline section of the forum. I'll have to search for it.

Here is a link to my post replacing the tailshaft bushing. The replacement is on page two of the post.

http://www.montecarloss.com/community/ub...309#Post1038309

Last edited by Fred SS; 07/19/16 03:58 PM.

87 SS, Harwood cowl induction hood, UMI trailing arms. Hooker 2050 Headers (Jet Hot Coated). Hooker Cat-Back Exhaust, Goodwrench 350, Ported TPI, Trick Flow 56cc alum heads, SLP runners, Comp Cams 260AH-12 cam, Trick Flow 1.5 roller rockers, TCI 2400 stall converter, Denny's 3.5" Driveshaft, GBodyParts GNX Replica Wheels 18x8 & 18x9.
#1065923 - 04/11/20 03:21 AM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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GregO Offline
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GregO  Offline
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North Haven, CT
Old thread here but what the heck. Ain't a bar, restaurant, microbrewery or honky tonk open for a 1000 miles.

Been through this driveshaft saga as well, just seeking a smoother machine.
Had a local shop Camerota state the OE shaft was bent and talk me into a new shaft, same diam and thickness mated to the original slip yoke.
New one vibrated much worse than the original. After a few re-balances no improvement. They also loaded it with grease making a mess and taking paint off the frame.
Had the transmission tailshaft bushing replaced at another shop but no improvement and seemed pointless after only 50000 miles or so.

Took it to Bill Mitchell he stated the new rear yoke had too much clearance to hold the the u-joints centered so he bent it to tighten the fit.
Helped some but picked up a used OE shaft (supposedly removed at 7 miles to build a drag car) and not perfect but best of all.
Been in there now 20 years and no plans to touch it unless I upgrade to a GN rear been sitting in the garage but needs shafts and rebuild.

OE shafts have the U-joints held in with some kind of plastic as if its molded while fixtured.
Maybe it absorbs vibration and maintains factory quality alignment rather than allow clearance needed so that any technician can slap it together on a bench with no Engineer in sight.

#1065925 - 04/11/20 06:55 AM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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mmc427ss Online content
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mmc427ss  Online Content
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Pottstown, Pa
The plastic in the u-joint is injected and forms the internal clip to hold the cup from moving. Heating the joints will cause the plastic to ooze out of the holes for cup removal.

Have you tried a poly rear trans mount?
Bob

#1065935 - 04/12/20 03:04 AM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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bobinmesa Offline
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bobinmesa  Offline
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MESA, Az
I changed out the tail shaft bushing, still have a small vibration but it is much less noticable

#1065975 - 04/13/20 01:21 AM Re: Vibration from 65 mph and above [Re: Kawaiikeno]  
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86ttop Online grandpa
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86ttop  Online Grandpa
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Here is a trick an old time mechanic told me to do to my 86, Jack up the rear and place on jack stands, remove the wheels/tires and install lug nuts to hold the brake drum on, put a hose clamp around the drive shaft at the rear u joint area and mark the shaft 1,2,3,4 at the u joints and tighten the clamp with the screw at the #1 position and run it up to speed, the one where the vibration was the worst,if that doesn't cure the vibrations, loosen the clamp and move it to the #2 position and so forth til the vibration is either gone or barely noticeable and good luck!!


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