I have a 92 Seville with a automatic tranny that wont engage in morning for the first approx 5 mins then its fine the rest of the day. Shifts perfectly and doesn't slip at all. Its just after it sits over night you can start it up and put it in any gear and you can feel/hear the solenoid engage but the car will not move no matter how much you rev it up. Then just out of nowhere it will finally engage and run perfectly after that.
I just did a filter change and put fresh fluid in it also.
Anybody know what could cause this? Thanks in advance.

 

Most likely it is the rubber seals inside the trans are hard. When cold they contract, and will not seal pressure to the clutch packs. Once the fluid gets warm, it softens the seals somewhat, and they are able to seal.
Only "fix" for this condition is a rebuild. Pouring any snake oil in will not "fix" it.
Second most common problem would be the torque converter draining overnight. If the bushing is worn, and there is wear in the valve body, it can allow air to enter into the converter, and it will drain the fluid out. When you first start it, the converter will have to fill full of fluid before it will move the car.
If it is taking 5 minutes before it moves, it's the seals causing the problem.
To check for converter drain-back, check the fluid level BEFORE starting it after the next overnight park. If the fluid level is waaaay high(more than an inch over "Full Hot"), the converter is draining. A drain-back problem will only take a few seconds before filling the converter, and the car moving.

 

Thanks for the info. Ill probably start looking for a replacement or getting it rebuilt.