I have a 2000 Chevy Blazer 2 wheel drive with 128,000 miles. My trans. started jumping in and out of torque converter lock up at a wide ranges of speeds. About the same, when the trans downshifted and the engine revved over 2000 rpm the truck started emitting a loud screeching noise. I took the serpentine belt off thinking that was the source and it is not, so I assume that it is coming from the trans. Thinking that the TCC lockup switch had went bad, I dropped the pan and put it in. The bottom of my pan was cover in silt-like (not metallic) residue, I changed my trans fluid/filter about 2000 miles before this incident. I test drove the vehicle and it is still making that screeching noise and when it down-shifts it acts like it loses power and struggles to accelerate. I don't think the power issue is engine related, because the engine runs very well. Anyway, I am going to replace it with a good used one or rebuild this one. Does this sound electrical or mechanical?

I know that the early 4L60E's seemed to have some durabilty problems, so I would like to put a newer year trans in it. Is there anything that would keep me from putting a 2001+ trans in it ? Also will the trans out of a silverado or tahoe 2001+ fit in it. Thank you very much.