LS1Beginner

I just finished a 98 F1 Camaro. ZL11 Cam, CNC heads (Patriot stageII), SLP long tubes, 3.73 rear, and had clutches and servos beefed up in the 4L60E.
Torque converter is a Yank 3600 lockup. Flexplate is a TCI. Motor mounts (front and rear) are polyurethane, suspension is from Steve Spohn.

I am having an intermittant vibration in 3rd gear. I can eliminate the vibration by unlocking the converter (flooring it and letting it re-lock). Shifting into overdrive also will stop the vibration. This vibration can occur anywhere in the 2000 - 3000 RPM range. Above 4000 it goes away. If the car is in park there is no vibration up through 6200, or in neutral either (meaning it's not the driveshaft and rear). The onset of vibration appears to be associated with lockup in third gear, almost like the relative position of converter and engine makes the difference. I have consulted all manufacturers (converter, trans) and they all point at one another.

Any help you guys can provide would be greatly appreciated.

Thanks,

Larry

jay_99z

iTrader: (5)

Have you double checked your converter bolts? I had a little vibration (intermittent) with mine. Only did it in drive. When I pulled the converter I found one bolt was finger tight. They now have locktite on em.

LS1Beginner

I used blue locktite on both the flexplate and converter bolts. I'll check it though - it's not that difficult to re-examine the converter bolts.

Thanks.