This is a symptom of a serious problem, at least on 1G DSMs. Shifter movement is not generally normal in DSMs. Having the shifter move around, especially in 5th gear, or popping out of gear (even once or twice) could be an indication of a loose retaining nut inside the transmission. Several 1G DSMers have had the rotten experience of having this nut come off completely, and consequently blasting a hole in their transmission. This problem only affects FIFTH gear - gears 1 through 4 and reverse do not appear to suffer from this difficulty.
Those who are uncertain must know that both by Paul Lyons and Ashok Babu had their transmissions fail on them. Don't take a chance on this one, since the inspection procedure is easy.
This problem does not appear as common on 2Gs, and at least one owner has reported that there was a loose nut in his shifting assembly that was causing the shifter to pop out of 5th. This is NOT the same nut that is involved in the 1G problem.
2G owners who suffer from problems with the shifter moving around in a gear OTHER than 5th gear have a different problem. David Gowlowski reported that his transmission failed because of a bad bearing on the input shaft, which corroded away until his car would not shift into second gear. He believed that this bearing was part of a bad lot. "I received an email the other day about the moving shifter I had last year and realized I hadn't sent something to the collective unconscious for the archives, so here goes.
First of all, if any of you have a shifter moving when you get on or off the gas in 2nd, go pound a beer before you continue.
Okay, now go pound another. And another, and another... Okay, do you have a hard time focusing yet? Good. Final warning- this happened over 6 months ago and I have struggled to forget the whole thing, so some of my terms and descriptions might be off...
Some cars may have the shifter move in 5th gear because the retaining nut for the drive shaft is loose. Unfortunately, because of the way the tranny is put together and the tolerances involved, this is the only moving gear that can be fixed by the excellent vfaq out there about this. If the shifter is moving in another gear it is probably because of slop in the tranny. How is that possible? Well, on my 53K Talon AWD it happened because the load bearing on the input shaft was part of a bad lot. As a result, the bearing corroded and pitted and basically slowly disintegrated until the bearing (cage type- holds rollers) was so loose that the whole input shaft could move. Not a lot, but enough that the shifter could be seen moving about 3/4" when a load was applied or removed from the tranny, and eventually enough of a slop that I couldn't even engage 2nd gear. Interestingly enough that bearing was the ONLY one that showed that level of deterioration- you can see it below.
With the help of TJ from DST (thanks man!) I got the tranny to DRW in Poway (by San Diego). They've built trannies for GN's and 4x4's forever and even offered an unconditional 12 month warranty, and did an excellent job (I also highly recommend them). Inside my tranny enough metal had ground off components from the slop that I ended up needing almost a complete tranny rebuild, to the tune of ~1800 bucks. The worst part was that if I had bought an Eclipse it would have still been under their 60K warranty, instead of Chrysler's 36K ;( I talked to a lot of people about what to do and what the problem might be before I knew, and RRE, DST, M&S Recycling, and other digest members indicated that more and more 2G's are needing tranny work for loss of 2nd gear, so maybe that lot of bad bearings was a big one. For the sake of the DSM community I hope not. Anyway, I did take the opportunity to put in an ACT 2100 and lightened flywheel from RRE, so it was not a total loss. Yeah honey, the bill was $2300...;) Good luck- I hope this did not apply to you."