94 transmission problem

New to forum, have read many posts regarding transmission problems, but none with my symptoms. I have a 1994 4Runner, 3.0, automatic. I replaced the engine about 6 months ago and everything has been fine. About 3 months ago, the transmission will not engage when put into drive. I have to manually put it into first, then second, then third. It will go into overdrive on it’s own and downshift normally unless you go below 10 to 12 MPH. Then it drops in to “neutral” or nothing. I have to manually put it into first (second won’t engage) again and shift manually back trough the gears to third. Based on another post on this board, I used a jumper on the diagnostic socket under the hood and I get the O/D off light and the check engine light flashing constantly (no pauses). I removed the ECU fuse for a minute and tried again, same result. All gears seem to work properly on their own. I have visited a few forums regarding 4Runners, you guys seem to be the most knowledgeable.

Sorry for being so longwinded for my first post, hope someone can provide some guidance.

Thanks, Bill

I have the same problem Bill with my 93 4runner,hope someone has the cure.
Thanks Ed

If you haven't flushed the transmission in a while, try doing that. Sometimes old ATF will cause things to stick.

Its is most likely your shift solenoids in the Tranny. I had mine go out about a year ago. I was manually shifting from 1st,2nd, to Drive when I finally broke down and had the dealer fix it. The dealer charged me 554.95. If I didn't manually shift, it felt like I was starting out in 3rd gear.