somebody broke or didn't connect the crank sensor
If same engine and transmission models, yes.
Yes, it is inside the pan.
Mopar ATF+4
it will fit but the electronics in it are different so no
The most compatible and completely interchangeable transmission that can be used with a 1999 Jeep Grand Cherokee Limited is the 45RFE transmission. This is from a 2000 Jeep Grand Cherokee. Only this model year is compatible with the 1999 model year as the vehicles shared 127 of the exact same parts.
The flywheel, also called a flexplate, is in between the engine and transmission.
where is the fill tube for the transmission on a 2001 jeep grand cherokee
Mopar ATF+4
Using a very clean small plastic funnel pour it down the transmission dipstick tube.
I recommend you have the A/T fluid changed every 36,000 miles.
Try changing you oil and if that does not help you will need to rebuild the tranny or replace it.
Power steering fluid, transmission fluid and filter, cooling system.