FYI -- Cliff Notes bottom paragraph for those lazy peoples

Symptom:
During acceleration, heavy or light, the car has a horrid vibration that shakes just about everything.

What I think is the culprit:
Lightweight flywheel.

Testing done to arrive at conclusion above:
Obvious acceleration issues. However, if I am going... say, 65 MPH; take the car out of gear and just roll at the said speed, I no longer experience vibration issues. That leads me to believe that it is not the axles, and correct me if I am wrong - but if it was the axles, it would still shake at 65 MPH no matter what gear/rpm I was at.

I've also considering the wheels being off-balanced. I drove up to a shop today, had them remove and rebalance all wheels. Still experience symptoms above after wheels have been balanced.

There are alot of factors I'm sure that could be causing this. I've also done alot to my car recently, including rebuilt motor and trans. For the record, I did NOT experience this problem PRIOR to pulling the motor. I then put the motor back in, and experienced this problem. I then pulled the trans, rebuilt it from the bottom up, and I'm still experiencing the same problem.

Also - at idle, I dont "feel" a vibration. The engine doesn't "appear" to shake when giving gas at a stand still. Any ideas guys... because I'm clearly out of them. I'm pondering dropping the trans again tomorrow and removing the lightweight flywheel.

Cliff Notes: Bad vibration during acceleration. Think its a lightweight flywheel. Tires are balanced, and don't experience during 60 MPH roll when in neutral.

 

I would say it is in the diff.

 

If it was the flywheel, you would feel the vibration at a certain given RPM not a certain given speed. Did you check if you get the vibration in any gear. If you are sure that the problem appears only at a given speed and is not RPM related then the guilty part is anything rotating from the LSD to the wheels.

If you find that the vibration appears at a given RPM then it could be
-FW (disengage the clutch and rev. the engine alone, if the vibration appears, it
could be the FW or the crankshaft)

-Clutch friction disc (with the clutch engage and the car out of gears rev the
engine to see if the vibration is there, engage and disengage
the clutch to see if the vibration comes and go)

Hope this help


[Modified by JPP, 11:23 PM 10/18/2002]

 

The problem exists under acceleration period. 10 MPH through 70 MPH. Any gear.

 

Yes sorry I did not catch that in your initial post.
Then your problem falls in the "RPM related" category. If you do the test of revving the engine with the clutch engage and disengage (while in neutral) then you should be able to pin point if the vibration comes from the engine / FW side or the clutch friction disc / tranny side.
May I ask what brand of FW you have? Usually FW are balanced at high rpm before they are sold to the public...
Did you put all the bolts in when reinstalling the FW and clutch pressure plate?

 

a bad axle will definately cause vibration under acceleration...

take it to a ntb or sears auto where you live and they will check it out for free (you dont have to have it fixed there)

 

Just tought you might also check your engine and transmission mounts

 

ive always found that under acceleration w/ lots of vibration, its always been a INNER CV joint. although hard to diagnose, the first time it comes up u never forget those damn inners. i should know from experience, ive broke about 8 axles so far.

 

Fidanza.

 

Hmmm... will do.

 

I'll be checking them today, as someone else made this suggestion to me.

 

Ok.. I'll see if NTB/Sears can figure it out.

 

Update: Motor mounts look fine. Hummmmm... I'm starting to doubt its the flywheel again. Putting it on a lift on monday to see if we can see anything with the axles. (Driving it while on the lift, looking for abnormalities.) In the meantime, anyone else who has experienced this problem or has any suggestions.. I'm open.

 

I has the same problem. On Friday my crankshaft skipped 5 teeth and likely has bent some valves...and one of the seals shot oil out of the timing cover...

I'd be interested to know what your problem is...I think mine is the crankshaft vibration causing the timing belt to slip....cause my cam gears are still lined up fine but my crank side ans balancer belt are all out of whack

I knew I had a problem cause I could make the vibration while parked


[Modified by satan_srv, 6:52 PM 10/20/2002]

 

I would also have to say inner CV... OR
Could be the shaft from the inner CV to the transmission housing.
The shaft OR bearing could be bad.. alot of times, you CANNOT visually
see anything wrong with them..

 

bump for weekday people.