1996 dodge ram 1500 4WD shifts into reverse fine starts off in 1st and will not shift into 2nd gear

Two things happen on the Dodge's. 1. the rear O2 sensor shorts out and meses things up. 2. the Inner seal on the Direct drum (3rd) shrinks and causes a delayed up shift.

take bottom pan off clean out your pressure sensor .. tends to get mini metl flakes caught up in there wich is also a bad sign that your tranny is going out but this will buy you atleast another 2 to 3 months

Hello,
problem is from the gear box. The gear box has developed a fault and that is why it starts out in 1st will not shift in 2nd will jump in to 3rd . Also, have your gear oil check to be sure it is not short.
You need to take the Dodge to your mechanic before the problem gets worse. This is not a DIY (do it yourself) job.
If you don't take it to your mechanic on time, you might end up damaging the gear box which is expensive to replace. It is still repairable for now.
I hope the above is clear.
Regards.

Sounds like the lockup converter. Any lights on the dash lit up? My need to have a shift sensor/solenoid replaced to repair the problem.

I don't have the shifting schematics for THIS vehicle .
However, they are available in the vehicle's repair manual. If you obtain this manual look for what is common between 2nd gear, final drive and overdrive this is your problem.
Remember they source of the problem may require a rebuild of the transmission. You may want to save some time and just give it to a repair shop.

check your solenoid in transmission its for shifting gears try that first

Have someone scan the transmission for bad shift sensors.

I had the same problem with my 96 Ram 1500. I thought I was going to have to pull it out and get it rebuilt or just replace it. That was at 134,000Km it's now got 210,000 and shifting like a dream. What I did to solve the problem was this, as follows:
1. No lucas transmission Fix makes things worse.
2. Get your self a new transmission filter and gasket
3. Grab Gunk transmission medic 12oz
4. Grab 7 Liters of Valvoline ATF+4 transmission fluid (Made for chrysler transmissions)
5. Drop the trans pan and drain all the oil, clean pan and magnet
6. start truck for 5 seconds and the pump will pour out another 1 liter
7. re-install filter, gasket and pan, then add your Valvoline ATF+4
8. Add, the valvoline, transmission medic and make sure you have the right level of fluid

That solved my transmission problems, instantly it was shifting better, I no longer had to let off the gas to make it shift. Now if you have large pieces of metal on the magnet, and it's totally covered in filings, you might want to consider rebuilding the trans. My magnet had usual clutch.         

Anyhow good luck, let me know if it did the trick for you.
Justin