on a 1984 toyota tercell wagon 4wd automatic transmission 3ac-can the timing belt tensioner pulley and spring be replaced by only removing the top portion of the timing belt cover?(that is without removing the bottom portion of the cover or the crankshaft pulley–the belt was replaced recently and now the tensioner needs to be replaced)

You should not have to replace the tensioner at this point. Was it not replaced when the timing belt was changed?
What makes you think it’s bad now?

No. I believe you need to remove the lower cover to replace the tensioner.

the tensioner was not replaced when the belt was, about 6 months and 15 thousand miles ago. now a noise that sounds like a bad bearing just began, behind the cover in the area of the tensioner. now i don’t have access to a garage or an air impact wrench, which was barely removed the crankshaft nut.

thank you

fyi-turnsout the tensioner & pulley can be replaced as above however, i had a defective water pump which i discovered by feel.