No movement in any gear
 

2003 Impala 3.4L 275K
Wife says after stopping, she couldn't get going again. Tried every gear. As if stuck in neutral. No symptoms before this. She had it towed home. As soon as the tow left, I was able to drive it into the garage. The trans fluid was old, dark but didn't smell burnt. I don't know what kind of fluid was in there but I had only serviced it once in 145K miles with about 7 quarts of Dexron III. Flushed it all with Castrol Dexron VI and new Carquest filter. Car's been driven 55 miles/day for the past 5 days with no further problem. Any idea what's the most likely cause? Dirt in a valve or solenoid? Just old oil, maybe clogged filter? I took the filter apart and although there are many very small metal fragments, I can't tell how clogged it is. Thanks for any insight.

If its drive-able now, you did what you could. It will fail again, but that might be awhile.

Well, the little I did does seem to have worked. But I've been watching transmission videos and I've found there's more I can do that I never knew. There's the Trans Go shift kit and beyond that, replacing solenoids. So if it acts up again, I'd try those before heading to a shop. And I'd recommend to anyone to look at those procedures if you're having trouble with your transmission. I'd say most can install the shift kit. Replacing solenoids is more involved but it's not rocket science. At least not yet.

Update: Well, she went a couple of months and got difficult again. Moves, but slipping and the high pressure pump whine. So, I did the Trans Go kit, actually just the springs for the accumulator in the pan. It's helped quite a bit. There was a bit more of the muddy gray stuff than I expected for only two months so clutches and more are on their way out. Slight whine now and then but not slipping. We'll see how long it lasts. Local shop wants $1800 for a rebuild. This is in Loganville, GA. Looks like I'll be pouring a lot of magical mystery fluids in before I go that route.

Update: The Trans Go kit helped a lot but there were still some minor issues such as occasionally not downshifting when going uphill and shudder going downhill. Pump whine now & then. Nothing really serious but I decided to do the solenoid kit as well even though the voltages were there for the solenoids. Took me all weekend - that's Friday night to Sunday night. It rarely goes like the youtube video, does it? A couple of the solenoids have small filtering screens which were only slightly blocked; didn't look that bad at all. And the ohms on each were in spec. Afterwards, I reset the TAPS with my chinese Tech 2 and added a bottle of Lubegard. By the way, if you've got a lot of miles, replace the trans harness. Every locking clip broke as I tried to disconnect them. Usually $56 or more, I got one at amazon warehouse for $12.75! The one I received was brand new and tested good. Couldn't believe it and they still have more, at least for the 4T65E. Now the trans is definitely better with none of the previous symptoms remaining - for the past week anyway. Alas, it still has 278K on it but with TLC maybe she'll go a while longer. Remember, at the beginning, this car did not move in any gear. Then other, not real serious problems popped up. Now it seems back to normal. So, don't give up. Change fluid & filter and go from there. And be sure it's not actually an engine problem.