1998 dodge ram manual transmission will not shift while engine is running

SOURCE: 1996 Dodge Ram Transmission shifting problem

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

SOURCE: 1999 Dodge Ram 1500 2WD won't shift properly

Sounds like the speed sensor on the rear axle.

SOURCE: transmission does not always shift into overdrive

Governor pressure sensor or solenoid is going bad. To replace them drop the tranny pan, remove the filter , and the parts are pretty ez to get to. These aren't cheep thou, but replace them as a set. Parts will probly run about $200.

SOURCE: My transmission is not shifing right

With truck running check transmission fluid level add if low

SOURCE: 1998 dodge ram 1500 loss of engine power, slight

Without a code to work with i know those trucks had a problem with the t.p.s. sensor . This will also cause erratic shifting of the transmission