I only take my 91 ranger 2.3, 2wd automatic transmission, for trips no farther than about 30 miles one way, Because I don't know if I can trust the trans?

I bought the truck at a good price last spring and I have put alot of parts in it, you know how that goes. As far as the trans goes , First I had to flush the radiator, added a larger trans cooler, changed the trans fluid,and filter,(did this again later, with coorect fluid). The 1st time the fluid was thick and black, but no burn smell, now very clean. I did this because I started to slip from 1st to 2nd, later I replaced the governor and made sure I had the steel weight on it. Also replaced the int-servo & overdrv-servo, and she ran fine, for about a month. Then I had another issue starting out in drive, it was a shudder/ like not in gear right.
I did the complete adjustment of the linkage underneath where the cable adjusts and at the shift lever, with the weight. It did seem to be off a bit.
After that it has been running fine, no problems through the fall and winter.

I did this all while the trans was in the truck, because I can't remove it where I live. I just wonder that if its been running good for the last 5 months, Can some of these issues return , or do you think these issues have been resolved because of no issues in a while?