well when i 1st bought the monte it didnt have a tach.so i got my tach put in and when id put the pedal down it would shift at 4k rpms.chirp both tires hitting 2nd gear.about a month ago this all changed for some reason.now it shifts at about 5,500-5,700rpms.i talked to my dad and he said my tranny might be goin out.what else could cause this?could it be that some gunk on the valve train finally came off?i havent changed anything since i bought it besides a tune up.

 

Do yo know how long ago the Trans was serviced? hen you pull the dipstick, does it smell burnt? I would drop the pan and see if the filter is clogged.

Its also possible that your bands are starting to slip.