High speed vibrations, you tell me why - page 1 - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.

• High speed vibrations, you tell me why by ORCoaster on 05 Feb, 2012 21:33
• Well on my 225 mile trip from the coast to Portland tonight I picked up some bad vibes and I am so rattled I thought I would ask for a second or third opinion on it. 
  
  So here is the situation.  Running at 60 to 65 MPH and the whole cars is buzzing along.  Fingers are shaking over the steering wheel, the rear view is moving so badly the lights in it from the cars behind are lines a half and inch long. 
  
  I push in the clutch and let the motor idle down and as I slow a bit the vibrations are still there but slack some as I drop about 5 MPH. 
  
  Would I be looking at new rear axles and bearings again?  I just did that about 5K miles ago.  Could I have just thrown a weight on the rear wheels?  Should I be checking the transmission or the axles?
  
  You tell me, I need a nights rest in a calm setting to think straight. 
• #1 by 8v-of-fury on 05 Feb, 2012 22:34
• Could be front wheel weights, cv joints inner or outer, transmission, bearings up front.. Any snow there? Some built up in the rim??
• #2 by guy plain on 05 Feb, 2012 23:20
• loose bolt on thi IP..the one one the bottom of the pump by the dip stick..??
• #3 by theman53 on 06 Feb, 2012 04:40
• If it doesn't go away with the engine RPM it is drive line related. I would guess you lost a wheel weight or there is a balloon in your tire. I had a rabbit with the rear tire that went bad on the inside and I didn't find it forever. Most speeds it was fine.
• #4 by ORCoaster on 06 Feb, 2012 08:13
• Some additional Info.  I had the car weighed down to the max.  2900 GVW, I passed it over the scales coming up Hwy 101 and the car was on the stops in the rear.  Buzzed the tires occassionally on the fenders crossing bridges when driving 60 mph.  Stupid expansion joints. 
  
  Being loaded as it was I am going to check for missing weighs first then, bearings and then driveline.  I do have one new axle on the drivers side but not sure if the other isn't showing it's age now.  Maybe all the hard pulling was causing it to show its wear.
  
  Still bulked up like it was I still got 48 MPG out of it.  Love that.
• #5 by ORCoaster on 06 Feb, 2012 21:55
• All wheels have their weights on.  Either on the inside or both in and outside of the rims.  So I guess it is time to jack up the wheels and give em a wiggle. 
• #6 by Dean Erickson on 07 Feb, 2012 18:01
• Did you have the front drive shafts out lately? I had one out abought a two months ago. I didn't get the drivers side tight, it came loose and made a intermittent viberation at anything over 40 mph.
• #7 by ORCoaster on 07 Feb, 2012 18:57
• Dean, if you are not located in the UP I would be surprised with a last name of Erickson.  Was a MTU grad myself.
  
  But no I haven't had the front axles off in a long time but replaced the rears about 4 months ago when massive bearing failure took the works out.
  
  So tonight I had just enough time to crawl under the car and jack each wheel up and check for trouble.  You know, binding, bearings grinding, top of tire moves half an inch when rocked, that sort of thing.  Result not much.  The wheels spun like a top when given a slight push.  No axle movement in the front that would lead me to think a CV was going out either.
  
  The only thing I had was a 1/4 inch wobble on the rear passenger side.  So I am going to pull the cap off that side and see if I can get the lock nut to give me one sixth of a turn tight without binding the washer to badly.  Then I will replace the cotter pin and hope for the best.  I thought I needed to drive across town for work tomorrow but that meeting got cancelled by work of a different nature.
  
  So is 1/4 inch of wobble enough to cause a wicked vibration?  I wouldn't think so but that is my thought on the matter.  Am I off base?
  
  
  
  
• #8 by rabbitman on 07 Feb, 2012 19:29
• 1/4 inch is too much but I wouldn'ta thought it would shake that bad. Spin the tires and see if you have a lump on one or a bent rim maybe.
• #9 by ORCoaster on 07 Feb, 2012 20:28
• Dang it,  forgot to check for tire bulges on the fronts when i had it up in the air.  Oh well, there's always tomorrow evening.  Hydraulic jack it quick to get under in four places.  Now that it has been up in the air shouldn't have to muscle it up that 3/4 of a inch to get it on the jack.
  
  Tires did spin true, I didn't see any up and down motion on them like they were out of round.  Might have to get a piece of chalk and hold it still and move in close to the tire to see if there is a high point. 
  
  I will keep looking.  And fix the wobble.
  
• #10 by 2strokesmoke on 07 Feb, 2012 20:56
• I had a vibration,on my 82 Caddy,which was difficult to narrow down,
  First let me explain: This truck had new everything (well almost) before going on the road. New wheel bearings,brakes,rotors,drums,hardware,full fron suspension and steering,motor mounts,ect...
  Had the same exact vibration,after installing new tires and wheels
  Turned out to be drive axels. (the truck had one reman and one rebooted)
  I installed 2 NEW axels from Advanceauto.com for a total of $125 (with online discount coupon) Lifetime warr.
  Solved my vibration
  Old axels seemed good- Go figure.
  I will add- the new axels were tight at first (even with a ton of CV lube) Took sveral days driving,to break in. Sounds silly,but I could feel the difference- I couldn't coast nearly as far,before they broke in. I drive the same route every day.
  If all else fails,maybe worth a shot.
  One thing distinctive about my vibration (aside from starting around 60MPH) I noticed that while going uphill-the vibration was much worse--going downhill was much less.
  Old axels appeared tight and didn't clack or chug on  tight turns.
  Good luck,Mike
• #11 by ORCoaster on 09 Feb, 2012 06:57
• OK, thanks Mike.  I did take the car out last night to see what types of weirdness would present themselves.  I went looking at an 81 turbo Caddy.  Didn't buy it though.
  
  The problem may very well be in the axles of the differential.  I noticed that if I slowly accelerated that the vibrations seemed to start right about 27 mph on the GPS Nave unit I have for a speedo.  If I let off on the throttle the went away.  Hit the throttle hard and they come back.  Definately have RPM of wheels or axles not engine correlation.  Kind of a Whump Whump Whump at the 27 mph zone. 
  
  I did tweak the motor mounts on this engine last weekend.  So I am going to start there as they say, go back to the last thing you did and you will generally find the problem.
  
  I don't have my Bentley with me so could someone do me the favor and summarize the engine centering process for me.  Do you loosen them all and start with the rear mount, move forward and then center it side to side or what.  I think that makes the most sense but then again it is a German engineered car and I am mostly German but with a healthy mixe of Polish too.  Good/Bad combo actually. Don't ask why.
• #12 by 8v-of-fury on 09 Feb, 2012 07:17
• Acceleration leads me to think CV joints..
• #13 by ORCoaster on 09 Feb, 2012 10:10
• One new one old axle.  Might just be the mismatch in age and wear.  Time to buy new?   Time to tighten hex bolts?  I'll keep ya posted
• #14 by theman53 on 09 Feb, 2012 15:35
• I am with 8v on this. I have had older ones hold up longer than newer ones too. Sucks replacing the same side 2 times before getting to the other side, but it happens.
  
  I think the process in the MK2 anyway was loosen them all, shake the engine and trans around until it settles, then tighten them all. I thought mk1 should be the same.