Transmission issue

I just changed out my transmissions in my 85 c10 Silverado LB from a 700r4 to a th350 because it was slipping gears and after I got everything connected and put 5 quarts of fluid into it I forgot to put the other 4 quarts in and went to go start the truck and it wouldn't move in any gears so I checked the fluid and realized it was low and I put more into it and made sure it was right at the full mark and I seen a fluid leak coming from under the truck and it ended up being my cooler lines leaking almost like the flares were big enough and the bottom cooler line had a hole in it so I cut a piece of it off that was about 4-6 inch and slipped a rubber gas hose over it and clamped it down and sealed the leaking cooler lines with JB Weld and they still have a small leak but I figured it was to small to hurt anything so I took it for a test drive and all the gears seemed to be shifting great I got it all the way up to 75 and then I got it home and went to back it into the garage and its like the reverse was out I had to press the gas almost all the way down and rev it up before it would even move just a little so I parked it for about an hour and went to go take off in it again and now its doing the same thing as before just sitting there when I press the gas in drive or reverse, any suggestions on how to fix it if its a simple fix or new transmission? Could it be the cooler lines not being properly fixed?