If I understand the description of the problem correctly, two possible problems come to mind.
First, it is possible that the small teeth on the clutch gear on the underside of the wind assembly may have been sheared off by excessive force. To check, you will need to remove the top cover, then the film counter assembly. The entire wind assembly will be removed with the film counter assembly, held in place by it's large return spring.
Carefully inspect the small pointed teeth on the upper side of the large wind gear of the wind assembly -- one or more of these teeth may have have been broken off. If this is the case, one or both of the pawls may have also been damaged. If so, the wind assembly will certainly need to be replaced. (Fortunately, the wind assembly for the OM-2, 2n, 1n and all but the earliest versions of the OM-1 are all identical, so donor parts are relatively common.) Be cautious, however -- if any of the tiny teeth of the clutch gear have been sheared off, they will almost certainly have imbedded themselves in the grease around the wind gears, either in the gears on top or those inside the bottom cover. (Rarely, they may also migrate into the meter movement, intermittently jamming the meter needle. Just be aware.) You will want to draw a tiny spring hook through the grease between each pair of gear teeth both on top and bottom, wiping the grease off the hook each time to check for any shards of metal stuck therein.
Secondly, if all the teeth are intact, the problem may be that the friction plates that operate the two pawls may have become sticky. In some cases, this can be corrected by simply soaking the wind assembly (separated from the film counter) is a bath of naphtha or lighter fluid while turning the gear and operating the two pawls and the plates that engage them. For a more thorough repair, the wind assembly can be disassembled using a 5mm driver to remove the nut on the underside of the assembly, then washing and wiping each part separately before reassembling. The wind assembly should remain dry -- do NOT oil or lube any portion of it!
On reassembly, note that one unique feature of the OM-2 and OM-2n is that there is a small white plastic cup that insulates the end of the wind shaft from a post attached to the upper side of the battery chamber. It is imperative that this white plastic cup be in place in that post before reinstalling the wind assembly! Sometimes it will stick to the end of the wind shaft when it is removed, and may be lifted out of it's place above the battery chamber, allowing the wind shaft to intermittently short the batteries to ground. Not Good! To check, shine a light into the side of the film take up spool while looking down into the opening from the top. If the white plastic insulator is not in place, use a spring hook to maneuver it into it's place in that post.
Hook the wind assembly onto it's return spring in the underside of the film counter, turn it against the tension of the spring and lift the wind assembly just enough for it's protrusions to clear the stop screw on the underside of the counter plate, then push the wind assembly into the film counter -- spring tension should hold it in place.
One more minor concern -- notice that on the top of the film counter there is a small gear with a finger sticking up that acts to move the counter forward one number with each wind. Below that gear is a post with a notch that straddles a matching tab in the body. This part may be 180 degrees out of place. When replacing the counter/wind assemblies, it's best to have the camera wound (turn the sprocket with your thumbs) and be sure that the finger on that gear is facing away from the film counter as it is installed. This will assure that the film counter will increment one frame during the wind stroke, not at the end. If this part is out of time, the film counter may appear to move backwards slightly at the beginning of the wind stroke, then move forward at the end of the stroke, sometimes more than one frame number.
