a used converter siting installed in a trans with really dirty fluid in it over 10 years could let the setiment sink to the bottom of the conveter.this could cause a imbalance in the conveter. i know conveters are zero balanced but i have seen where a weight is welded on the front of the conveter to achive this balance. its is possible that that weight could be knocked off. i am not a trans specalist like you are paul. i really respect your knowlage. im just giving sugestions based on the info provided.
Here is where it stands: Read the first post to get the initial details. Replaced harmonic balancer -- No change Replaced torque converter -- No change There is not nothing from the original motor that is on the new motor, but still the vibration persists. Used a vibration analyzer and found the following results: Velocity peak at 1300 and 1900 rpm. Smooth machinery will have a .2 i/s or less. This engine is .16 until it hits one of the above rpms and it reaches .31. It feels like a 2nd or 3rd order harmonic that is surging in the 25hz range. So my question is thins: Is this type of harmonic vibration normal on these engines? Since I have no one in the area to compare their car to, I don't have any other comparisons.
how about the drive shaft.... back in high school me and my friends put a chunk of lead on this kids drive shaft and it vibrated like crazy for weeks till it flew off.... so i think it could have a bent or outof balance drive line.
Take the driveshaft loose at the rear-end and roll it 180* and put it back on...it could be out of phase. Like 73rustymav said look for a missing weight
I had a similar vibration, took the shaft in for a straigtening and balance, and new joints. Lost about half the vibe. Still a little shaky, but doesn't wobble down the road like it did. Is this all happening while driving or just while running? I tracked mine down by jacking the back end up, revving it with the wheels up and spinning to 60mph where my vibe got worst. Then removed the wheels and spun it. Then removed the brake drums and spun it. It continued to vibrate, but at least I got those variables taken out. Then I rotated the shaft 180 and it improved a little. Then I got the balance and straight job and it improved a bit more. Still running the stock converter, and it sat for 15 years, so I wonder if that isn't my problem. Another thing I am looking at is pinion angle...
