There is a thunk or knock noise that my car makes, seems to be coming from the bellhousing area. I hear it under the following conditions:

If I am putting along at about 10 mph and I pulse the throttle, making the car repeatedly surge. It will knock after each time I hit the gas.

Somtimes when I put it into drive. Not always.

I just noticed tonight while doing a little road test that I heard it when I was cruising along (maybe 10-15mph) in second (with the shifter in 2nd), and I manually downshifted into first. The car downshifted and slowed down normally as you would expect, but as soon as it went into first I head that knock, pretty loud that time.

All these things seem to have one thing in common. They all involve a reverse in the flow of power, ie, going from a situation where the power is coming from the engine back towards the wheels to a situation where the power is coming from the wheels and back into the engine (like my last example with the downshift). Would this indicate excessive play in something?

Please note a couple things, all these speeds are estimates because my speedo is slightly off, and my tach is off as well so I cannot give you RPM information. Also, I have a brand new polyurethene transmission mount. Is there anyway that a torque converter can make these noises?

 

sounds like a transmission mount, torque arm mount or loose converter bolts.

 

 

Maybe a motor mount as well - my 1990 had a terrible clunk under these kinda conditions and it was a bad motor mount, causing the motor's torque to twist the tranny and tap the tunnel.

 

Sounds like the same thing I had. I had to replace the tranny mount and the torque arm bushing (both were stock rubber cracked and broken). If it is do it soon because you might be doing damage to your tranny.
Darrell