1996 dodge ram 1500 shakes and skips in overdrive what is wrong ?

sounds like torque converter clutch chatter, when your in overdrive the torque converter clutch goes into full lockup to make maximum engine RPM reduction in order to run more efficiently. when the torque converter clutches begin to fail youll notice a shaking or skipping called "chatter" which is the clutch slipping.

how to fix ?

try doing a transmission fluid flush and filter, that might save you. at worst your might need a new torque converter and a transmission cleaning.

thanks

If that fluid change doesn't work, you'll need a new converter. Also if you find a lot of junk in the pan when you pull it, rebuild the trans too. You could still have problems after the converter change if clutch mateial has found its way into the small passages. Trust me, I learned the hard way with my 01.

I actually just had this exact problem. My truck would run fine but when i was in over drive and slightly pressed the gas to accelerate it would shimmy unless i sped up hard. Replaced all my spark plugs yesterday and runs fine now. I was thinking it was a bad plug or 2 and seems as if i was right so far. If you change them your self its about a 2.5 hour job and a $35 dollar fix. All you'll need is a 10mm socket, flat t ip screwdriver, socket wrench, 3" extension swivel socket adapter and a plug socket. Questions just email me at tommy1244@gmail.com hope that helps

Well, that one certainly got by me! Mark Tommy's answer most helpfull! Bet he's nailed it.

tranny mount !!

tranny mount