I recently took all the sheetrock from an outside wall I noticed the sill plate along the bottom of the studs is rotted no termites maybe just dry rot is there any way to replace without tearing the whole wall down

You can replace the sill without tearing down the wall but it would involve removing the siding outside. You must cut out the old plate after installing jacking. This is not a DIY project unless you know how to support load bearing walls. Maybe contact 3 construction compoanies for bids. Listen toi what they recommend and then decide if you can do it or one of them.

I agree with Bob, of course. But first and foremost, find out how the water got in to rot the existing sill plate and correct.