I had my stock transmission rebuilt as a favor by a group of church friends around 178k. I thought these cars were pretty bulletproof until I came to the forums regarding the transmission.

178k isn’t so bad, and I had hoped for another run as we just had all of the timing, water pump, etc done in the last 10k. All was good but the car has been acting strange since the transmission rebuild.

First off, the car dies at stoplights occasionally. Rare, but has happened a few times. It starts right back up and acts like nothing happened.

Secondly, the car will over-rev second gear on occasion, typically on the same hills at same speed. During the shift it seems to go 1k over the usual before the shift.

Lastly, the transmission will cut out at times at any maintained speed, usually at highway speeds. It happens for a fraction of a second, enough to flicker the check engine light but you’ll miss it if not looking.

Nothing actually triggers a code.

Yes, I’ve taken it back to them and three times they’ve had it out and went through it with no change. Yes, I need a more skilled tech to look but that’ll probably cost more than the car is worth. I’m frustrated I paid those guys more than they even asked, prior to all the issues, but I’m not going there again.

 

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While I don't think this is related or causing your particular issues, it's worth mentioning because my prior owner 03 CL-S had a rebuilt auto trans. when I purchased it in 2019 with 51K miles.
The transmission would occasionally delay & 'hard shift' at low speed, from second to third, after a cold start when driving the car.
Since the auto trans was rebuilt, by the prior owner (shop in NY state), after noticing said delay & 'hard shift' I performed a 3X3 Aisin DW-1 ATF flush & the below #12 brown & #13 black sensor change.
I forget now, though I think they have to do with the third & fourth gear pressure sensors?
Anyway, this was done as a precautionary measure because there was no way for me to know what ATF was used prior to my ownership (age / condition / type) & while I was there these sensors were replaced with new OEM.
Surprise!
Upon removal, I found that both of these sensors had TWO #17 gasket (10mm) stacked upon each other while installed in their rightful locations.
My guess was that the trans rebuilder shop reused the old sensors and just haphazardly placed another gasket when reinstalling these two during the rebuild??
Or, maybe these two sensors were new cheap amazon / eBay aftermarket knockoffs and were the cause of the delay / hard shift issue??
No way to really know.
Finally, after the ATF flush & sensor replacement the car performed normally without a reoccurrence of the mentioned issue.
My brother has owned the car since July 2025 and has not mentioned any problems as of yet (knock on wood!).

 

Thank you for some avenues for possible exploration. Sadly, I’ve not had much in the way of responses or luck in tracing this down.

I did notice that when the problem occurs, it causes the D (drive) light to go out while the maint required light flickers for less than a second before lighting up the D again and driving normally.

 

I was doing some more research in the threads about flushing solenoids directly,though I don’t know which ones I should focus on for the 2nd to third gear shift rev.. Anyone know which ones to start with?