My 87 Ranger has an A4LD automatic in it. Since I got the truck it has shifted rough. It slams into gear when I put it in drive and reverse. It also shifts in and out of gear when I am on hills. It does it on flat ground as well but not as bad nor as often. I dropped the pan and it looked decent inside without any junks. Just normal material build up. Even though I do not have any fluid coming out of it, I bought a new modulator in hopes that is the problem. While I am doing some exhaust work I was going to replace it. However, do those symptoms sound like and adjustment problem instead? I am assuming the line pressure is too great and that is why it slams into drive. I have not had to deal with these very much over the years so please chime in on other possibilities you may think of.

 

the slamming into reverse and drive sounds like engine idle is too high IMO, check the vac line for the modulator to see if its cracked or blown off somewhere(had that happen in my Tbird)

 

I thought so as well. But it still did it even after I adjusted the idle.