I've got a 1994 C280 recently inherited with about 82k miles. The 'Check Engine' light just came on and I suspect the transmission (automatic) because it is sometimes not very smooth shifting (ie. upshifting late on heavy acceleration and then clunking into the next gear) particularly when cold.

I wanted to check the transmission fluid level, but I can't find a dipstick - is there one on this car? What does the 'Check Engine' light usually mean on this model?