Ok, when you checked the fluid did you check it with engine running and at operating temp? If so how much over full does it look.
Even though it has been about 4 months. It is possibly the cause. If you can syphon some out try that to see if fixes problem. If doesn't and no engine light it is most likely an internal failure.
After doing the above and if it doesn't fix it then you would be best off taking to a transmission shop to verify.
.
Wednesday, March 3rd, 2010 AT 10:26 AM