150k on auto trans. fluid flush last week. worked fine for week. trans now will engage for about 5 minutes (until hot) then wont remain in gear. High pitched grinding sound in transaxle area, even when out of gear. Possibly torque converter? Noticed that fluid is over full. Will that cause problem? Or, am i just in for a new transmission?

It could be as simple as you don't have enough trans fluid. It could also be a shift actuator/solenoid. Have you checked the level of your trans fluid?

one thing ive warned my friends to never do and that is to never have your trans flushed cause you may have new fluids but what about the trans filter its old and iots there for that reason to keep dirt and metal; shavings from the bands so try having your oil and filter in the transmission replaced , pull your trans dip stick and on a white piece of paper put a drop of trans oil that you have in your trans at that very moment it should be redish pink but if its brown and smells really bad then the problem is in the oil and filter . change it before u have to replace the whole trans

When was last trans fluid & filter change? (I'm assuming it's an auto. trans.) Trans fluid & filter should be changed every 30k or 3 years. I'd start there and have system flushed when you do the filter change.

When was last trans fluid & filter change? It's supposed to be done every 30k/3yrs or sooner if you do any towing, I'd start there and have it flushed.

the transmission forward band is slipping flushing or replacing fluid will not help you will have to overhaul or replace transmission the reason problem got worse after fluid replacement is that the dirty fluid actually helps to seal minor spaces in clutches and bands when new fluid circulates through passages it will pick up deposits and remove dirt sealing clutches and bands most trans shops dont reccomend replacing trans fluid on vehicles over 120,000miles or 180,000kms that haven had regular trans fluid maitenance for that exact reason

Try to check the trans mission gears of your 1995 jeep grand cherokee.The shift fork and the clutch sleeve of the trans mission is locking to the other gears .And then also check the starter motor and its solenoid.if the starter motor solenoid is destroyed or worn out replace .

If there is no fluid when you take off one of the lines (check both: the cooler might be plugged) while the engine is running, and there is fluid in the trans, then you have a bad pump inside the trans, or the valve body fell off. Either way, it's probably not going to engage. Ever.

I had the same problem I changed the transmission fluid & put a new filter in the trans, this fixed it good until I put my foot down to overtake the trans kicked down to 2nd gear & the hold light started flashing again & the trans started slipping again. I stressed over it for a day or 2 & then I took it out for a drive & thrashed it, Low & behold it came right. When you change fluid its impossible to get all the old fluid out because the torque converter holds a liter or two under pressure, so when I put my foot down some of the gunk blew through & blocked the pump it looses pressure & cant change gear. You need to get it flushed by a transmission specialist   

You are probably having ATF bubbles flowing through your tranny either from overfill or by using cheap ATF / the wrong atf. Consider a drain and refill 3 times (driving for 5 minutes in between a drain and refill. This time only use dealship ATF and I guarantee you the problem will go away.