98 Transmission

I just "inherited" a 98 Windstar 3.8 that I was told needed a tranny. I have a shop takes care of my trannys for me and gives me a great price on rebuilds, so I was planning on just getting it rebuilt. Once I got it home I tried to jump it and get it off the trailer, but no go. Got it into the garage and got it running, and it runs great. Has 160k, but runs like a new one. I put it in reverse, and it went right in, almost instantly. lots of 'grip' in reverse. I then put it in drive, and it didn't go in. Just like it was in neutral. I revved it a bit, it grabbed and actually spun the tires. It idled down, and was like it was in neutral again. I just parked it and figured maybe I would drop in a rebuilt tranny, maybe just sell it as it is. A month or so went by, its nice out, so I started messing with it again. Again, reverse is right on, drive is like neutral at first. I then placed the shifter in second, and it grabbed, almost like it was supposed to. move the shifter to 1st, idle goes up. Move it to drive, idle goes up. Place it in second, it grabs, and goes right into first. I do not work on trannys, and know nothing about them. Is it possible it may be a solenoid or selector switch? Any ideas on what to look for, or should I just go back to the idea of letting it go as is, or rebuilding it?
A brief rundown.
Reverse is good and strong. Drive at idle is like neutral. Drive above idle is good and strong. Put in second is good and strong. 1st is like drive.
Before anyone asks, I do not know the history of it, fluid is a bit faded but not burned and it at the right level.

I just "inherited" a 98 Windstar 3.8 that I was told needed a tranny. I have a shop takes care of my trannys for me and gives me a great price on rebuilds, so I was planning on just getting it rebuilt. Once I got it home I tried to jump it and get it off the trailer, but no go. Got it into the garage and got it running, and it runs great. Has 160k, but runs like a new one. I put it in reverse, and it went right in, almost instantly. lots of 'grip' in reverse. I then put it in drive, and it didn't go in. Just like it was in neutral. I revved it a bit, it grabbed and actually spun the tires. It idled down, and was like it was in neutral again. I just parked it and figured maybe I would drop in a rebuilt tranny, maybe just sell it as it is. A month or so went by, its nice out, so I started messing with it again. Again, reverse is right on, drive is like neutral at first. I then placed the shifter in second, and it grabbed, almost like it was supposed to. move the shifter to 1st, idle goes up. Move it to drive, idle goes up. Place it in second, it grabs, and goes right into first. I do not work on trannys, and know nothing about them. Is it possible it may be a solenoid or selector switch? Any ideas on what to look for, or should I just go back to the idea of letting it go as is, or rebuilding it?
A brief rundown.
Reverse is good and strong. Drive at idle is like neutral. Drive above idle is good and strong. Put in second is good and strong. 1st is like drive.
Before anyone asks, I do not know the history of it, fluid is a bit faded but not burned and it at the right level.

1st, 2nd and reverse has the highest pressure and its enough pressure to push your clutches together to move the van. When your in Drive, your missing that high pressure and your slipping clutches. Most common is your Transmission pump is failing along with its pump shaft. It also, pushing bits and pieces all thru the transmission and cooler. I would just get a rebuilt unit and let that one go for rebuild.. You could put a new pump in your trans but have many other problems including piston leaks from higher pressures. Its best you do it all including a Trans Cooler flush and a after market Trans cooler to get another 100k outta the van for around 2k 2.5k.. If its worth it..

Ive seen trans rebuilt for 1200. Core 600 and your labor.. 1k for labor.. Just a ball park.

There is a shop in the area will pull it, rebuild it, and install it for $650. Only has a 3 month warranty though. The place I usually use gives me a 2 year unlimited milage warranty (+ $35 p/h labor as quoted from MOD) and will do it for about $850, but I gotta do the pull and install.
That aside, I am not following what you are saying. I understand that you say 1st 2nd and reverse have the highest pressure, but what I do not understand is while it is sitting in my garage at a stop why can I move the gear selector to drive and it is still like it is in neutral (unless the rpms are brought up, IE revving the engine), but at the same stopped position in the garage can I move the gear selector to 2nd and it grabs (at idle)? I don't mess with trannys other then to replace em, or fluid/filter changes, but I was under the assumption that at a stop any forward gear (D, 2, 1) would place the transmission in 1st, but would limit the upshift to whatever gear was selected.

Thinking out loud here. Could the shifter, trans and trans range sender be out of adjustment, so the shifter indicator and stops are out of sinc with the actual trans gears?

I have no idea, I do not touch trannys if I can help it. I will most likely either get a rebuilt or let it go (sell it) like it is, but I would still like to know what the problem is. I could understand if it were the same problem in all forward positions (d,2,1) but with it grabbing with the selector in second and not low or d, I just don't know.

The Transmission Range Sensor (TRS) aka neutral safety switch will run you very roughly $50.....and it is mounted on top of the transmission case.
Common failure......you might get lucky.

If unlucky, sadly, the best long term approach is relpace with a remanufactured unit.
If the pump is shot.....it will have put junk throughout the unit, as tartersauce has mentioned......and repairing just part of the unit could lead you to a money pit situation.

I am at about 100K and 7 years on my FORD remanufactured unit.....and it is doing very well.
Added a auxillary cooler and went to yearly fluid exchange.
I put 6 ounces of Auto-RX into the tranny fluid about 1K miles before doing the fluid exchange.......and have a Magnefine inline filter on a cooler line.
The thought is that this will help to clean out around the fluid solenoids.
Overkill?....yes......it cost me about $2800 for the remanufactured unit.....installed......don't want to go through that again.

I take the inline filter off when the yearly mission trip......towing a trailer comes up........to maximize fluid flow through the coolers.

It is very worthwhile to verify low speed radiator fan operation......very easy to do.......radiator fans should be ON and STAY ON whenever you are sitting still.....and the A/C is ON.
There is a dropping resistor for low speed radiator fan low speed operation....
This has a major impact on transmission temperature in stop and go traffic.

I am driving fewer miles each year now.....so I could safely push the fluid exchange to every 2 years.