transmission fluid on 2001 BMW 540i

I have a 2001 BMW 540i. transmission failsafe program, keeps coming on on my dashboard. I have looked for a place to check the transmission fluid and cant find it. Does anyone know where I can find this at?

Asked by for the 2001 BMW 540i
1 answer
It is an allen key bolt on the side of the trans, suggest having a professional check, considering you cant even find the inspection hole.