I have a 1987 4WD automatic. Recently had work performed on the van in which it was taken to a transmission shop to look it over(previous owner had records of the transmission being rebuilt within a couple thousand miles of me purchasing it from him). The van seems to not want to shift unless I let off the gas for a second, then get back on the gas and then it shifts. I’ll be at 3000-5000 rpm and it’s not shifting into the next gear. Since getting it back from the transmission shop, the issue seems to be worse, especially for 3rd and 4th gear. The van has 260,000+ miles on it. Is this par for the course or fixable? While this is a 4WD van, I haven’t even tried the 4wd, these issues are all for when it’s not in 4wd. Thanks for helping out a newbie who isn’t super mechanically inclined.