Shifts hard in/out of 1st/reverse or slips and revs high before catching(90 inline-6)
First off; I'm a newbie to both Jeeps and automotive maintenance in general, feel free to correct me on my terminology and advise me on what further information I should be providing.
I have a 1990 Cherokee Loredo with the Automatic 5-speed transmission that has been running great for awhile, until yesterday...
I took her out on a steep mountain road and used the "Power" mode on the Power/Comfort switch, which helped tremendously climbing miles of switchback roads. (I've never really used it before)
On the way down however (back in 'comfort' mode) the transmission started losing grip while in first gear, I had to lightly gas it and let off the gas in order to get the gears to 'catch', which was followed by a horrible lurch and grinding sound.
Now when the vehicle is idling it randomly bucks forward like an anxious horse at the racetrack, and when first accelerating the RPM's climb to about 2.5k-3.0k before the gears engage, followed again by the 'lurch' and grind.
When backing it out of a parking spot after taking a look under the hood it has the same problem; high RPM's then it catches and lurches/grinds.
When shifting from 2nd gear to 3rd, 3rd-4th, 4th-5th, the transmission seems fine; it maintains it's speed/RPM's pretty consistently once I'm out of first.
This beast has about 209K miles on it, and I think this is the 2nd transmission, is it time to replace it again or are there other steps to take before I head to the pick-n-pull?