1999 Jeep Wrangler Automatic transmission started slipping

I never hurts to change fluid and filter after 50K on any vehicle. This may or may not solve your problem. But, while you're under there, be sure all the wiring connections are clean and secure. This is where you will probably find your problem. Let us know.

Thank you for your quick reply. I checked the fluid again last night, and it seemed a little milky (foamy)
The fluid level looks fine. It did look a little dirty at the bottom of the dipstick when cleaned with a towel.
I put the tranny in gear and it seems to take a few seconds (or by giving just a little gas), then the tires begin to move (vehicle is up on jacks stands)
2 of 3 times i could get to about 15mph @ 1500 rpms and that was about all the tranny would do before seeming to slipp back into neutral. No cluncking or jarring.
If I put the car into reverse the tranny makes a constant slight slipping noise almost like it isnt fully engaged into gear. If I go from reverse to neutral the slipping noise continues while in neutral, but then goes away when put into drive.

If the trans fluid looks foamy or milkly, that is indicitive of water contamination. Apparently you haven't pulled the pan and drained the fluid yet. In pulling the pan, you will lose only about 3 qts of fuid. the fluid capacity, with the Torque convertor is about 7 quarts, so you may have to empty the pan a couple more times to purge most of the water in the system. I wouldn't even start the vehicle again until the fluid has been changed. The noise you are hearing may be the pump, or you may have "toasted" the low clutch pack. We will be able to tell a lot about what has happened by what is laying in the pan. Please advise.

When you say to empty the pan a few more times to get all the fluid out, would you please explain. Do I need to empty fluid in pan, put pan back on, start, then pull pan again, etc, until all 7 qrts are out? I have enough new atf4 to flush out the tranny. I bought some cheaper stuff to use for flushing. Is it ok to put back on the old gasket and filter until I have drained all the fluid out, then replace the filter and gasket once all fluid looks free of water? A old jeeper friend told me that if there is water in the tranny it would most likely be coming from the radiator as the tranny is completely sealed. I read on some other forums about a drain hole on the top of the tranny that is known for getting water in the tranny if the vehicle is in the water too far. Do you have any thoughts on that? Would you say to replace the radiator? Thanks James

Your old jeeper friend is correct, on a rare occasion, coolant from the radiator can enter the trans coolant lines and get into the trany. But, I doubt this is how this happened. Towards the top of the trans is a vent for pressure relief. When a warm transmission is submerged in cool water for any length of time, the cooling effect draws water in through the vent. What I would do is, after the trans has sat for a while, pull the pan and filter. Drain as much fluid as you can. Paying close attention to what is in the bottom of the pan. Install the new filter and gasket without glueing the new gasket to the trans, just snugging the pan bolts. Fill the trany to proper level and try it to see if it works. At this point, we don't know if it works until you try it. If everything seems to work ok, then, I would drain the pan again, reusing the new filter and drive it for a few days. At some future point, I'd drain the trans again, using the same filter, and you should be good to go. Keep in mind, water is heavier than ATF, and any water in the system is going to settle out in the pan if the vehicle sits. Judging from your first posting, I'd say you have about a 50/50 chance of no internal damage. What's laying in the pan will tell the story. Let me know.