2000 silv shifting

hi is this normal when im going up hill the trans shifts to 4 it will shift lover only if i press the gas have way or more it does not stey in 3 or 2 for long also 1 to 2 it will shift in 1500 rpm i also have new toyota sacoya but when im going same hill it will down shift to 3 or 2 whit no problem. the truck run good but shifting sucks is this normal i wish the trans is from the sacoya its more quicker response
thanks for any help