I got this problem yesterday, and it’s only when the car sits for awhile where it won’t shift out of first until about 4,000 to 5,000 rpm then after that initial shift it’s completely fine for the rest of the ride until you let the car sit for a few hours or overnight again. I received a transmission light this morning but turned it off/on again and it went away. Checked the fluid when it was hot and it was red but was about a 3/4 quart low. Filled it up but still has the issue. It doesn’t clunk into 2nd when it does it, it shifts normally. Any ideas of what I can test? Any advice is greatly appreciated!

 

I am thinking.

When you checked that fluid, the engine was running in "P" I will assume.

Back to the pondering.