Automatic Transmission

99XJ
How do I figure out which automatic transmission I have? The service manual lists four or five.
Do I change the fluid myself, or go to a shop? This would be my first time if I do. Are there any tools that would make my job easier?
I want do do that, because sometimes when I drive in traffic for a long time, when I stop, the transmission disengages (I think) with a clunk, but shifts normally otherwise. Also somethimes when I stop at a light, I hear rumbling from the mid-section of the engine compartment as if someone put a boulder on the hood...kinda. Don't know how better to describe it. At the time I am in Drive and have the break pedal depressed. If I shift up or down the "dial" and then return to Drive, the "vibrating boulder" noise disappears. Sounds familiar?
Thanks in advance
Boris

hey with a 99, if you have the 4.0 you most likely have a AW4(43LE) same as most other years, if i was you change the tranny fluid yerself, go to napa and get a tranny filter kit, there like 17 bucks, and drain it, drop the pan, be sure to clean off all the gasket material off the pan lip and the tranny base and then change the filter and install the new seal and replace filler her up and you should be good to go, as for the sounds your are hearing i cant speak to that i have beat the shit out of my trannies, and havent had any problems like what you are saying is happening, HTH..
Maier

maybe a messed up u-joint.

thats what usually causes clunks .

pete