Still fighting vibration

by **charliek** » 23 Apr 2009 2:21

I have balanced tires, lifted trans to line drive shaft up with trans and rear. I am going to remove driveshaft to have it checked. I hope that does it it is making me nuts. I feel it the most in the clutch pedal. There is no vibration when the car idles and I rev it so I guess it isnt the fly wheel.

by **drewcrane** » 23 Apr 2009 12:40

brother i have been in constant search for the vibration in my car and i have gotten rid of most of it i still have some body/frame harmonic imbalance of some sort, i did notice when my engine is running my power steering pump has a wobble at the pully, i have seen some of the old chrysler bullitens talk about this problem and i will perhaps get a new pump and see, but for you check all of your accessories that are belt driven and see if they wobble cause if they wobble at idle i wonder what they do at speed :s022:

by **burdar** » 23 Apr 2009 14:09

When do you feel the vibration? Is it just on acceleration or is it there while cruising? Does it increase with vehicle speed? If you put it in neutral while moving down the road does it go away? You said that you have had your tires balanced...have you checked them for flat spots or if one of them has a belt that is separating?

I had a vibration after putting 18" wheels on my Stratus. I had them balance a few times but the vibration was still there. A shop accidentally ruined the wheels and had to buy me knew ones. Then the vibration was gone. I must have had a bad wheel the whole time. Make sure one of your wheels doesn't have too much runout.

by **charliek** » 25 Apr 2009 6:54

burdar wrote:When do you feel the vibration? Is it just on acceleration or is it there while cruising? Does it increase with vehicle speed? If you put it in neutral while moving down the road does it go away? You said that you have had your tires balanced...have you checked them for flat spots or if one of them has a belt that is separating?

I had a vibration after putting 18" wheels on my Stratus. I had them balance a few times but the vibration was still there. A shop accidentally ruined the wheels and had to buy me knew ones. Then the vibration was gone. I must have had a bad wheel the whole time. Make sure one of your wheels doesn't have too much runout.

The vibration is there above 55 mph and gets worse when speed is higher.If I put it in neutral it does not go away. If I rev the engine in neutral while not moving there is no vibration. It starts at around 55 and get really bad at around 70. the tires are new and the car did not shake right before restoring with the same tires. I feel it pretty severely through the clutch pedal.

by **Jon** » 25 Apr 2009 13:54

Sounds like it's from the tailshaft back. How are the bushings?

I rotated the drive shaft 180 but no help. Maybe worth a try it's quick and easy to do. BTW: Mine was balanced many years ago so I have eliminated that for now.

by **burdar** » 25 Apr 2009 15:47

charliek wrote:
burdar wrote:When do you feel the vibration? Is it just on acceleration or is it there while cruising? Does it increase with vehicle speed? If you put it in neutral while moving down the road does it go away? You said that you have had your tires balanced...have you checked them for flat spots or if one of them has a belt that is separating?

I had a vibration after putting 18" wheels on my Stratus. I had them balance a few times but the vibration was still there. A shop accidentally ruined the wheels and had to buy me knew ones. Then the vibration was gone. I must have had a bad wheel the whole time. Make sure one of your wheels doesn't have too much runout.

The vibration is there above 55 mph and gets worse when speed is higher.If I put it in neutral it does not go away. If I rev the engine in neutral while not moving there is no vibration. It starts at around 55 and get really bad at around 70. the tires are new and the car did not shake right before restoring with the same tires. I feel it pretty severely through the clutch pedal.

By taking the car out of gear at speed you can eliminate a lot of things. Since the vibration is still there with the trans in neutral at speed...you know you don't have an issue with the engine, trans or flywheel.

Since you say you really feel it in the clutch pedal, that leads me to believe there is a problem with the driveshaft. The driveshaft could be vibrating witch would vibrate the trans... witch would vibrate the pedal.

With the drivetrain eliminated, it can only be the driveshaft rearend or tires/wheels.

by **transman** » 26 Apr 2009 17:49

Another thing you might want to check is the angle of the driveshaft.
When springs start to flatten out, it can/will change the angle of the driveshaft/to diff. pinion shaft. This can cause vibrations, and in extreme conditions cause premature clutch wear. There was an article about this problem a while back in one of the performance magazines. When I worked for a GM(sorry) dealer, GM had problems like this with their light duty trucks that had leaf springs. You might also want to find out if your tires are separating. Lots of areas one can have to cause your problem. In 1971, I bought a new 340 Duster. At 60 miles an hour, the thing shook like crazy. The dealership balanced the tires a number of times(on the old fashioned bubble balancer, but until I took it to a friends tire shop, and he put in on a high speed tire balancer the problem couldn't be solved. On the balancer they found out the wheels themselves were not straight. From the factory the inner part of the wheel was not aligned properly with the outer rim. They changed the wheels, and the problem went away.
Also you might want to check the bushing in the transmission extension housing closely.
Good luck in your hunt.

transman :s002:

by **wolfman** » 27 Apr 2009 17:58

It's all great advice on here,but do get the driveshaft balanced by a pro shop it did the trick for me. The guy that did mine said the factory only balanced them to 55mph,what truth there is in that I don't know

by **charliek** » 28 Apr 2009 23:03

Thanks for all the advice. I eliminated tires since they were new and I recently had them rebalance to double check. I thought the trans was angled slightly down so I shimmed it up and it seems to line up with the driveshaft now. I just dropped my driveshaft off at Mr. Driveshaft to check the integrity and balance. Will let you know.

by **Moparman1972** » 28 Apr 2009 23:36

The transmission is not supposed to be parallel to the driveshaft, I don't believe. Dave or someone had a nice diagram. The transmission and rear end are supposed to be at 2 degree angles to the driveshaft, if I remember correctly.

by jr » 29 Apr 2009 5:52

by **dave-r** » 29 Apr 2009 8:54

Great diagram!

The second example is the one you should aim for. Maybe with the pinion just slightly down from there to allow for the slight rise as the car is powering along.

You need at least 1.5 degrees in each UJ (they don't like to be completely straight for some reason) for a total of 3 degrees between them.

Ideally you want the car to run along under power with exactly the same angle in each UJ. Otherwise they are oscillating at different frequencies. Which causes harmonics. Which cause vibrations.

by **burdar** » 29 Apr 2009 12:41

charliek wrote:Thanks for all the advice. I eliminated tires since they were new and I recently had them rebalance to double check. I thought the trans was angled slightly down so I shimmed it up and it seems to line up with the driveshaft now. I just dropped my driveshaft off at Mr. Driveshaft to check the integrity and balance. Will let you know.

Don't rule out the wheels/tires just yet. Like I said earlier...I had a vibration in a new wheel/tire combo and had it balanced on a "road force" balencer. I got charged over $100 and the vibration was still there. It only went away once new wheels were put on the car. If the driveshaft checks out OK...look at the wheels/tires again.

by **charliek** » 02 May 2009 3:19

The same wheel and tire combo didnt vibrate prior to engine and trans being redone.

by **drewcrane** » 02 May 2009 12:26

ok dave is right i ended up slotting my trans mount so i could get the trans angle down, i found later model trans mounts that had the mounting holes about 1/ 2inch lower that my mount that came on the car, again your not alone i still have an unwanted vibration in my car but slotting my trans mounting bracket did reduce the vibration somewhat so i know i am going in the right direction :thumbsup:

do you have an angle finder? if not you can get one at a hardware store :nod:

by **christer** » 02 May 2009 13:08

charliek wrote:The same wheel and tire combo didnt vibrate prior to engine and trans being redone.

What engine/trans combo are you using? What exactly did you do with them? Did you switch motor- and/or trans mounts for instance?

by **Jon** » 02 May 2009 14:36

drewcrane wrote:ok dave is right i ended up slotting my trans mount so i could get the trans angle down, i found later model trans mounts that had the mounting holes about 1/ 2inch lower that my mount that came on the car, again your not alone i still have an unwanted vibration in my car but slotting my trans mounting bracket did reduce the vibration somewhat so i know i am going in the right direction do you have an angle finder? if not you can get one at a hardware store

I think you guy are correct with this one. A few years back I replace the trans mount which brought the tailshaft up. A new vibration developed as a result.

by **charliek** » 03 May 2009 6:52

I had the driveshaft balanced and the vibration is 98% gone. The slight vibration that is left feels different. I think it is more related to the wheels. It feels like it is more in the seat of my pants. I dont feel it in the clutch pedal. Im bringing it back to the tire shop to double check the rear wheels again. I feel it the most at 72 mph. Even if it doesnt get better it is definitely livable.

Vibration problems.