What you are dealing with is a 25 year old tranny that has been used and abused. It did not receive proper maintenance and it is on it's last legs. This is very common for the KM145 tranny. They get used and abused and fail. When they are properly maintained they will run for 300-400K miles. The KM145 is a cheap trans to replace. You can typically find a rebuilt tranny for under $1000. It is super easy to replace and with a buddy you can replace it in just a few hours. I have replaced this tranny well over a dozen times and I can do it in under 2 hours all by myself.