Hi Guys. Great site... been learning a lot here. I bought a 2006 S Convertible automatic (Wrong forum, I know... there's quite a bit more traffic here) for my daughter and we love it. Great car. However, the transmission was doing a little kick in the back bucking once in a while. I did a transmission drain/fill 4x using the guide from on here. I used Valvoline Maxlife ATF, which I've read to be compatible with the Aisin 6 speed automatic. Since the fluid change the shifts seem to be great for the most part... but once in awhile after driving for about 20 minutes the engine will pretty much free-rev while accelerating. We're talking once per 30 minute drive, roughly. I have never been in the car while this happened and trying to get my 16 year old to describe what's going on is like asking my dog to do geometry. For reference, I used to be a shop manager and haven't let anyone work on my cars since I was her age (for the most part)... so I'm not a complete idiot with cars. The only issue I've noticed since the fluid change is a slow 3/4 upshift once in a while.
I'm leaning towards a solenoid being bad.

Update... I just got a little more detail... today she was accelerating normally and got around 40 mph and the car seemed like it popped out of gear, the car revved freely to redline a couple times, then she let it idle back down and tried giving it gas a few times... then it ROUGHLY went back into gear and was fine afterwards.

Any ideas here?

Thanks.
-Mag

 

I ended up dropping the transmission pan, replacing the filter, used Fuchs ATF instead of the Maxlife, and turned the K2 solenoid spring adjuster thinamabob two turns CCW and all is right with the world... so far.

 

I don’t know how many miles you have on it. I don’t know your budget or skills - you have some, based on your update.

i have a 2005 hardtop - owned since new. Had a shop do a valve body rebuild in 2015 @ about 110k. The car lives with my daughter in San Diego. It was doing all sorts of weird stuff past 170k. At 181k - Feb 2025, I had a shop in SD rebuild it. It was expensive - $5800? but it included a rebuilt torque converter, and conversion to an air to oil trans cooler - getting rid of that beer can heat exchanger. I got the conversion plate from a company in Europe ( Poland and Ukraine ).

All issues resolved. This is a favorite toy, and won’t ever be sold.

 

Also - heat is the enemy. Cold it was ok - once it got hot from being stuck in traffic, it acted up badly.