96 3.3 grand caravan OD works and doesnt work

i have a 3.3 96 grand caravan in OD it sometimes shifts to OD or sometimes just stays in drive as at driving 80km i nearly running 4k RPMS is it a sensor or just change the tranny filter or what would it be

it comes and goes isnt perment just while driving if i park and stop and try again it usually works again

Flush the transmission, use the right fluid (ATF+3) and cross your fingers. If it's showing an engine code, then it might be the solenoid pack, or speed sensor.
On second thought....at 80km/h, 4000rpm sounds like the van is in limp mode, in SECOND gear, not 3rd. Do try the speed sensor and the transmission flush or flush/filter/fluid change. (do it yourself, if you can)
Also, try this: remove the ECM fuse for 5 minutes (under the cover next to the battery it's a red tiny fuse on the end towards the strut tower). then re-insert the fuse and drive the van. Does it shift right then? Replace the speed sensor.

Hope that helps!

I agree, but I would use ATF+4.
See http://www.centerforqa.com/

ah ok ill try that as soon as i get a nother ac compressor mine went now u cant drive van and u cant bypass the damn thing with a smaller belt

how do u flush the tranny can u buy that at canadian tire

There's pro's and con's to flushing the tranny. Some say it might loosen up any debris hiding in it and possibly foul up a passage. Others just recommend draining, filter change, and refill. Some will run it and put a few miles on it and do the drain, filter, and refill again.
There is a link within my last post for licensed ATF+4® suppliers. One is Super Tech which is Walmarts brand.