I purchased an "AGRITEC", "AT20" tiller attachment for my tractor and it says to check the oil level at each use. The only oil openings I see are the fill hole on the top of the chain cover and drain hole in the bottom of the chain cover (the chain cover is approx. 14" tall x 9" wide x 2" deep, and the required oil capacity is 1.7 pints of SAE 90 EP). There is no way to check the actual oil level. There is a chain tensioner bolt about three quarters of the way up on the chain cover. The manual doesn't even mention the chain tensioner or show it in the exploded parts view. The manual also shows a "Level Plug" about one third of the way up on the chain cover, but it's not there. Can someone tell me how to check the oil level without draining and refilling to the correct oil level each time I use it? Thanks for your help!