my 1986 blazer s 10 makes a screeching sound like grinding gears, ive changed the fluid in my rear end and i put in a new transfercase and nothing worked, it starts getting rough after a while does anyone know what the problem could be?

 

does it do it in all gears. what about park and reving the engine. try putting the tranny in 1st then go to 10mph and let off gas then put i into 2nd and at 20mph shift into 3rd which gear sounds louder? but dont go over 20 mph in 2nd though it will make weird noises lol as mine lost manual 2nd gear cause of whoever had it before me. makes a loud click grinding sound and viebration at your feet. but in od it will shift fine. but try that and post back

 

thanks for the info but i sold my blazer, im just gunna find a k5 instead of the s10