I have a 1996 Dodge Ram 1500 2x4 318 v8 automati, when I start it,it idles good,1st and 2nd gear are good but when it shifts into drive it falls on its face,already changed theplugs, coil,dristributer

Governor pressure controls the 1st and 2nd shifts. After that is the 3 and 4 solenoids. you would need to look at the pressure when driving(takes a scanner). pressure is 20 to 30 PSI from 1st to 2nd, depends on acceleration. After that the pressure will jump to 100+ psi. Did you replace the governor solenoid and sensor? They are on the passenger side of the transmission and sit in a block that detaches from the valve body.

I hate to tell you but it sounds like your transmission was rebuilt incorrectly and need to be corrected or tossed and start anew, new transmissions for your truck are roughly $1,600. I'm sorry to hear about your problem.

the transmittion keeps shifting in & out of gear between 45 & 50 mph it shifts to a higher gear then a lower then higher then lower till I get above 50 mph whats the problem & how to fix it

Could be as simple as low transmission fluid, but it can also be your shift solenoids or gonked up valve body. Star with checking your transmission fluid level. On that vehicle its pretty simple. There should be a yellow dipstick. Vehicle needs to be on and on operating temperature. Gear selector in P or N. Pull the dipstick out and see what it reads.

!996 that's pretty old school, I don't think that has a shift on the fly feature. Maybe once the hubs are locked in.

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

It sounds like when you had the trans service don't he didn't do something right. He might have put the wrong fluid in. Does the trans make noise? Sounds like the trans is going in your truck.

mine does too on a 1997 dodge ram 5.9l automatic tranny from first to second it is jerking and jumping and then finally shifts into second i just had the tranny rebuilt probably 20 miles ago so as soon as you figure out the problem let me know asap my number is 2282432853

sounds like your iac valve this is on the throttle body and controls idle