Loud grinding at 5000 rpm !HELP!

[20secdsm]

The car is a 91 GSX AT
I got the car with a dead tranny. I just got it back from the shop so I took her out for her first drive, got her up to about 5500 and out comes this very loud grinding sound!
The car seems 100% solid at lower rpms. Oh and this is comming from the motor not the tranny. Please help!

 

[sparkey956]

go back to the shop it could be a number of things and if it is there fault they will fix it

 

[20secdsm]

Last nite I revd her up in park and guess what , no grinding! just the expected lifter chatter. The car will be back at the tranny shop in the morning. I hope they make it right but hell it took them TWO MONTHS to rebuild the tranny! I'll update soon I hope.

 

[20secdsm]

The shop said it is a rattle on the bottom of the car. But why is it gone when the car is in park?