engine revs high but car is going quick...like the tranny isn't up to speed.....this goes away after a few miles, but it is quite annoying, and I imagine its not good for the car...

Any error codes? If you don't have a reader or don't know the "key on key off a few times" trick, you can have AutoZone / Checker read your computer for free. My guess would be the TCM (transmission control module) - only a guess, though...

check your fluid level in the trannsmission first, may be low, as fluid heats up and expands symtom goes away. or fluid may be old and and sludgy may want to try flushing, if fluid is brown and smells burnt you may have an internal problem, like burnt clutch packs.

Check your Vehicle Speed Sensor. Just replaced mine. My 95 JGC 5.2L would not shift into overdrive and was running 50% higher RPMs. Parts are cheap($50-$60 sensor & housing adapter) and repair is easy (30minutes) if you get the same connector. The sensor is on the back end of the transfer case near the drive shaft to the rear wheels. If I remember correctly, it is error code 15.

To check for the error code, turn your ignition On-Off, On-Off, On then count the times the Check Engine Light blinks. There are short pauses between digits and long pauses between multiple codes. The last code it will give you is 55 which means that is the end.

Good luck,

check the Throttle Valve cable, I had this problem, in my 94 Grand cherokee 5.2L, the tip that connects the TV cable to the throttle body broke, and it wouldn't shift at all just rev real high, i was forced to drive form the garage to my house only a block away at 10 miles an hour, b/c I didn't want to hurt anything.

does it shift if you let off the gas?A very common thing is the t.v. cable or the lever on the trans gets rusted and sticks.make sure that it moves freely.if it sticks try some kind of rust penetrant.Another common item is that the front clutch seals inside the trans could be worn out.that makes it not want to shift from 2 - 3

Just fixed this same problem on my 98Grand Cherokee-Went to Advance Auto and put it on their dash plug-in analyzer(Afree service). The code read speed sensor, which I bought for a relatively cheap price and changed out in 10min. tops.It is on the bottom of the transmission. "Problem Solved". They then had to reset the engine's computer.