Re: Engine and gearbox vibration/noise

[sbender@dsd.es.com (Steve Bender)]

 >      As I accelerate in any gear I start to get excessive vibration
 >      from the engine/gearbox/steering wheel.  At about 3500 revs the
 >      engine note becomes noticably harsher and the gearstick starts
 >      vibrate, it feels like the car is going to shake its self to bits!

First of all, inspect your fan... Is it dinged badly or missing a blade?
At 3500 RPM one of these off-balance can make a lot of racket.  Barring this
the following flowchart is how I'd try to identify the problem:


                                                        YES = vibration/noise
                                                        NO = smooth runnin'
                / Road Test \
      NO ===== |  3500 RPM   | ===== YES
      |         \ 4th gear  /         |
      |                               |
    What                        / Road Test \
    Problem?        NO ======= |  3500 RPM   | ======= YES
                    |           \ 2nd gear  /           |
                    |                                   |
                    |                              / Standing   \
                    |                             |  3500 RPM    |
                    |                      NO === |   Clutch     | === YES
                    |                      |       \ disengaged /       |
                    |                      |                            |
                    |                      |                        Flywheel
                    |                / Standing \                      or
                    |               |  (Neutral) |                  Internal
                    |        NO === |  3500 RPM  | === YES          Engine 
                    |        |      |  Clutch    |      |             8-(
                    |        |       \ engaged  /       |
                    |        |                          |
                    |       ???                      Clutch
                    |     See note                   Pressure plate
                    |                                Internal gearbox
                    |
           Carefully prop up car
          with rear wheels removed
               /          \
      NO ==== |  3500 RPM  | ==== YES
      |        \ 4th gear /        |
      |                            |
      |                            |
Wheels out of balance         Prop shaft
Bent rims et. al.             out of balance


Note:
If you get this far with no indication of where the problem is, you may wish
to try the road tests again noting differences under load at 3500 rpm verses
no-load (downhill) at 3500 rpm... A difference here may suggest an engine/
gearbox/clutch problem that shows up only under load.  Otherwise you're on
your own.

-Steve-