Been having transmission problems with my car. The tranny is slipping (mostly when it is cold, after driving for about 10 mins it doesn't slip). Engine light came on and shows a #3 solenoid failure. I've been looking all over the net to point me in the right direction. Some history on the car. We drained the tranny fluid and put new along with some treatment, help a little but not much. The top half of the engine was taken apart and cleaned for oil sludge about 36000 miles ago.

Now, I've seen where the planum(sp?) may be clogged and causing this error and found plenty of comments where they state where most times it isn't the solenoid but something else that is making it look like it.

Anyone have any ideas on what I should look at first?

Sounds like you have an internal leak in the system, probably from the valve body. When it is cold, everything shrinks a little which opens gaps in seals gaskets and metal parts. When things heat up, seals and gaskets may become more pliable and metal parts will get tighter. Thus you have this hot/cold anomally. Need to get it to a tranny shop before it finally gives out. They can do a pressure test and tell you what the damage is.

Thanks. That makes sense. When my boyfriend did the fluid change there was a loose line in the tranny that he put back in but I'm going to have him go back in there and replace it. Stay tuned....

Make sure he checks for any wires he may have disturbed. This could explain the sloenoid error.