I need so help, please and thank you.

[nismo240sxdrifter]

I have searched everywhere for wiring diagrams of an S13 auto tranny and cant find one so I have a question. I recently had to be a new tranny in my s13 so I had a tranny from a 96 so I rewired it and put it in the car. It ran fine with no problems for 3,000 miles or so unless I hit a big water puddle. If I went through a deep enough puddle of water my tranny would keep slipping out of overdrive and into drive until it dried out. Just recently within the last 1000 miles or so the tranny has been consistently slipping out of over drive and into drive even when its wet, when it slips if take my foot off the gas it will go back into over drive but the overdrive light on the dash blinks on and off about 7-8 times then stops and does it again when it decides to slip again. Do you guys think that my tranny is going bad or you think that its only a wiring problem? The tranny only has like 101,XXX on it and never had problems in the S14. Thanks for the help in advaned guys. I cant wait to get enough $$$ to go 5 speed.