Howdy Guys,
Finally got my 96 JGC on the road after a complete tranny overhaul at AAmco. It is a 4x4 with the 42RE. I have a couple of problems now, which I don't know if they are related or not. The first is that when I first drive it in the morning, after about 1/2 mile, it will stutter drastically, almost like I am turning the switch off and on. It does this for about 30 seconds or so, then smoothes out. It still will shudder a little every so often but seems to run ok the rest of the trip. The most I've driven it at one time is about 15 miles. Want to stay close to home to shorten the walk if she dies on me!
The second problem is while I'm driving it, most of the time it will make small upshifts and downshifts by itself. I don't increase or decrease the throttle and it shifts by itself. I've tried turning off the OD but that doesn't seem to make any difference. Does this sound like a tranny problem which maybe needs to be adjusted, or should I just take it back to the trans shop and let them fix it? The problem is the shop is over 100 miles away and I am concerned about getting there.
Appreciate in advance the advice, looking forward to doing a total restoration on the beast over the next year or so.

 

I would suggest taking a look at the throttle position sensor as the symptoms sound the same. A bad TPS can cause rough idling, shuddering/stuttering of the motor, transmission shifting in odd ways. There is a way to test it and if you do some Googling I'm sure you can find it, but if you've never replaced it I'd just pony up the $40 for a new one.