I just finished my motor and, when I'm driving down the highway my car will vibrate violently when I'm running higer RPM's in 3rd or any engine speed in 4th. When I hit the gas and put it into overdrive, the vibration goes away. What kind of problem does this sound like to you guys?

It was either caused by the power of my new motor or the fact that my tranny cooler got a hole in it and it lost 2 or 3 quarts of fluid.

Let me know what you guys think the problem is and what it will take to fix.

Thanks!

 

4th=OD

Perhaps you mean the vibration quits when the TC locks up? I would check the fluid level first, very accurately if possible.

 

With 4l60e's, I thought there were 4 gears + overdrive.
I'll take the car to a tranny shop tonight to have them check the fluid.
Does it sound like my 3-4 clutchpack is about to blow?

 

If it helps anybody with diagnosis, the tranny also started to smoke the other day as I sat in stop and go traffic.

I've got a vigilante 3600 stall in it.