A "Shifting" Problem

I have an annoying problem I was hoping someone may seen before. I am getting a hard shift from 1st to 2nd every so often. It ssems like it will happen for a day or two then be ok, after a week it'll start happening again. Almost like a piece of dirt gets lodged somewhere then clears or something.

Anyway, here's the conditions - I do allot of city highway (ie traffic) driving. When I'm in stop & go mode with top speeds of say 25 or 30 (then stop again for a few secconds) it will occasionally slam into 2nd grear, lurching the whole vehical. The only other time this happens is sometimes first thing in the morning (the first shift of the day). Then after that it seems fine - untill I gat in that stop & go mode again.

Any and All thoughts are appreciated. It is a 99 JGC w/ the 4.7L and Select-trac 4wd. 108k miles - I did have the tranny flushed @ 93k miles and I wondering if that may have had something to do w/ this...

I'm having a similar problem with my 1999 GC with 102K miles. I get the "hard shift" between 2nd and 3rd sometimes too, and the RPMs are always higher than usual right before the shift. I haven't noticed that it happens only when it's cold, but it doesn't always happen.

Any one have any ideas?

Thank you for your help!

My first recommendation with shifting problems is to check the transmission fluid (best when the vehicle is warm). Be sure there's enough fluid. If it's low, add some transmission treatment such as Lukas brand. That's a good first-response. If that's the issue you should notice an improvement right away.
For some reason flushes on older vehicles tend to do more harm than good. It's usually better to just drop the pan, replace the filter, and refill fluid.

Write back with your results. If the problem persists it could need a band adjustment or other transmission repair. Hopefully the tranny flush didn't hurt anything.

Thanks! I got the transmission flushed yesterday because you and my friend's mechanic both mentioned it could be the problem. I think maybe cleaning it was overkill, but the shifting problem seems to be resolved.

The mechanic mentioned that he'd had a similar problem on a 2000 GC. He took it to the dealer to get the computer reset, and that fixed the problem. So, if transmission fluid doesn't fix it, might try that.

I havn't checked the fluid level lately but it was good a couple months back - and havn't noticed any leakage. I'll pick up a bottle of Lucas on the way home tonight and see what it does. I've used their injector cleaner and think it's good stuff. Anyway, I'll post back in a few days