Nice little 1612. Why do you think it's a 72? That style came out in 73 and the 1612 designation, I think, started a little later. Do you have the serial number? Your tractor may be newer than you think.
OK, that's enough to tell me (combined with the picture of course) that your tractor was made anywhere between 1976 and 1979 which makes sense with the 1612 designation instead of Jim Dandy and the Power King name on the hood instead of Economy. They changed from Economy tractors to Power King tractors in the mid 70s.
Good thing I checked the fluids.
Motor oil was OK so I changed it anyway.
Rear end was full of oil. Left it alone.
Transmission was full of water. Flushed it with oil several times and filled.
I then cut 2.5 acres of grass without a hitch.
May I ask how much fluid you put in the tranny? They only get half a pint. It should not be filled high enough to run out the side hole. That's too much. A quick way to tell if it's at the right level is to stick your pinky finger in the side hole and bend it at 90 degrees down. The tip of your finger should just touch the top of the fluid. If you filled it till you spilled it, it will end up in the rear end after it ruins your seals.
Yes, congratulations, you're the pround father of a 1978 Power King 1612. Happy looking little thing too. By the way, you'll like the fuel mileage. I mow an acre and a half 4 times before I think about filling it up... and it's only a 2 gallon tank!
That 18hp you say is over your budget is actually a 16hp from the looks of the air cleaner. Both the 16hp and 18hp have very distinct air cleaners and both are very different from one another. The 18hp is one to steer clear of unless you like working on engines... ALOT. I also like the duals. The one with the home made loader is 14hp. On the 16hp tractor, I like how the guy (or someone) reinforced the mower deck around the bottom. He did a nice job. Tuff Bilts are cool no matter how you look at them.