Problems with my Transmission
 

I have been hearing this screeching sound coming from my transmisson every time it shifts into 4th gear. If I get on it pretty hard that's when I hear this noise, is this a band stretching? I have also been thinging about getting a 700R4 Tranny, Can anyone tell me if this would be a good switch from my 4l60.

I have been looking at buying a transmission from this company

http://www.transmissionhead.com

Has anyone every purchased from them before?

Any input would be greatly appreciated.

Thanks
Tuff