3 speed manual transmission

My cj5 has a 3speed manual transmission it leaks an old man said he had one and drained it filled it with gear grease and it works fine any one know if this will work

i would not recomend that that tranny is not that hard to rebuild or take apart were is it leaking fromi rebuilt one it trashed the counter cluster i dont recall any seal other than the front imput cone and the tranfer case

That doesn't sound like a good fix. Those are cheap and easy to rebuild, but i would upgrade it to a T-18 4 speed with granny low for crawling offroad. Way better tranny and was a factory option. Thats what I did, bolts right in place of the 3 speed.