Hi my 2001 volvo s60 2.4L T wont go past 20 mph or above 2000 rpm i recently did oil change and transmission oil job any clue as wat it may be.

 

You need to have your car scanned for the check engine fault codes - no point in guessing without it. Considering you did a transmission job, you should double check your fluid levels using the proper warm up procedure. You can find a friendly indy tech to scan, rent an OBD2 scanner from Autozone or similar or buy one at Harbor Freight or onlin.

 

Sounds like a throttle body or ETM issue to me.