Do I need to rebuild the transmission or replace it

, the van runs great is shifts good except when it goes into 5th gear ledgerx and I have to put it on Overdrive to stop it from jerking is it just a quick fix by changing the transmission filter

I am still thinking that you mean once it's in 5th(overdrive) it starts jerking and you turn the overdrive off and it downshifts and stops jerking? I'm not sure if changing the transmission fluid and filter is going to help it or not,but it's worth a try to see what happens(a lot cheaper than a rebuilt transmission,over $2000.00).