95 318ti trans problem

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

time to replace transmission or car

Why Is My Automatic Transmission Slipping? If you have an automatic transmission and it "slips" while you are driving it-that is, the car engine revs without the power going to the wheels-the most common cause (though not the only possible cause) is low transmission fluid. If the slipping is caused by low fluid, it will get worse as the transmission gets hotter.
Why Is My Manual Transmission Slipping? A standard ("manual") transmission uses fluid too, but leaks aren't a common issue; a standard transmission could lose all its fluid and never slip at all, though eventually it would lock up while driving down the road. If you have a standard transmission, and it's slipping-the engine revs but it doesn't transmit power to the wheels-the problem is usually in the clutch.
Further down in the article I discuss how to diagnose this problem.
Sounds Like Low Transmission Fluid to Me

Definition of Diagnostic Trouble Code P0841 Category: Powertrain Definition: Transmission Fluid Pressure Sensor/Switch "A" Circuit Range/PerformanceNote: This definition of P0841 is applied to all manufacturers

Hi Ken:
Sounds as if the linkage is out of adjustment. Did something specific happen to cause this to start to occur? If you look at the linkage, there will be some point where you can shorten or lengthen the rod that attaches to a lever on the transmission. One way will make it better, the other will make it worse.

trans oil temp sensor will make this trans act up and a possible tcm update may be available for these cars

you can try changing the filters and fluid to see if it helps. Tim

Dip stick comes out of dip stick tube coming from transmission (side of trans) Look real hard on the side of the transmission behind the engine you will see it.

The second issue sounds like a neutral safety switch.

This is a sensor issue. It can be from a couple of different sensors. The VSS, or vehicle speed sensor is the main one. Loose or faulty wiring can cause it, a faulty PCM can cause it, or the Throttle Position Sensor can cause it.

Check your transmission fluid level - sounds like it is low.