The transmission goes into neutral when you are driving in drive

Though it will not harm your transmission to shift into Neutral while your vehicle is in motion, the additional wear on your brakes by leaving the transmission in Drive will be negligible over the life of the brake pads. It is that minor. NEVER, EVER go into neutral while slowing down to a stop, for 3 reasons: 1.
https://mechanics.stackexchange.com/questions/3902/automatic-transmission-is-shifting-to-neutral-while-approaching-stops-bad

possibly not an adjustment but a faulty transmission actuator not shifting the ratios according to throttle setting and vacuum reading
check for leaking/ missing vacuum hose or problem actuator for the transmission

10 Most Common Transmission Problems

www.transmissionrepaircostguide.com/10-common-transmission-proble...

Ever notice that while driving that the car hesitates or refuses to go into gear? ... For automatic transmissions, you might notice that when shifting into drive or park ....Neutral and park gears no problem, but drive, 1st, 2nd and reverse engages ...

Trans Goes Into Neutral While Driving - Transmission ...

www.transmissionrepaircostguide.com/topic/trans-goes-into-neutral/

Jun 5, 2015 - When I put it in drive, and begin to drive away the transmission will put itself in neutral. When I slow back down, it will go back into gear.

Have you retrained the gear? From memory think goes motor running foot firmly on brake park to neutral three times, neutral to reserve three times, neutral to drive three times, keep going thru all gears Then drive car normal for ten minutes minium as you usually would.

no country stated, no engine or exact transmission, real name.
see our USA pages
see all those, engines and matching transmissions
be wise to saY WHAT DRIVE TRAIN IS THERE.
if in Europe with a Diesel why leave both facts out.??????
you have transmission flare, (false neutrals)
lacking even one clues as to where you are, or what drivetrain
is a totally wasted POST, IMO.
see gen2 grand Cherokee, list below, must the helper guess?
why?
if car is USA< and say if 42RFE or 5-45RFE trans?
most posts fail here due to people thinking all cars are the same
sorry NOT.

http://www.factorychryslerparts.com/productSearch.aspx?&ukey_make=1064&ukey_model=15529&modelYear=2004&ukey_category=0&ukey_driveline=0&ukey_trimlevel=0&ukey_modelRange=0&isOnSale=0&searchTerm=

your transmission needs replaced.

Transmission fluid could be low, or transmission could be on way out.

p0705 is the transmission range sensor which tells the ECM what gear the transmission is in neutral/reverse. Which was probably happened when you lost Drive gear

Transmission range sensor may be failing. I would test it for opens and shorts.

Try checking/adjusting the linkage. My 99 3500 TD has a similar problem when trying to shift into Drive. I have to shift to drive then slam down on the shift lever to get it to engage. Once in a while it will pop into neutral if I hit a large bump or something. I've just been too lazy to crawl under the truck to do anything about it.