All right my 4L60 has been making a sound i would describe as a squeal inbetween shifts under hard acceleration. I mainly notice it between the 2-3 shift. Any thoughts on what this could be? Sounds like something is slipping in there but i don't think it should be making that much noise. I had a 97 V6 w/ a 4L60E in it and i never noticed any sound like this.

Also, how come the car shifts before peak power between the 2-3 shift (IIRC the peak power on the LT1 is right at 5k)? However, if i hold it in two it will run freely to 5k. It shifts right around 4600. The 1-2 shift seems to happen well into the yellow/close to redline. Thanks for any help.

 

My car squeals between shift sometimes, its the serpentine belt slipping

this might help