you have 722.6 tranny which doesn't have dipstick and uses expensive fluid ($15/liter) $250 is a good price assuming they will drain almost all the old fluid out since your tranny has a drain plug from the torque converter. so if $250 includes draining old fluid from both the pan and torque converter drain plug, replacing tranny filter along with pan gasket, and refilling with mb approved tranny fluid, then that is a good deal. dealer charges around $400+ for a job like that.
also you can buy tranny dipstick on ebay for around $20-25 any time, or if you are cheap then buy 4.5-5 ft of 1/8" steel cable which is very flexible from any hardware store and use that as a dipstick. when fluid is fully hot the level should be between 55-65mm from the bottom of the cable, so you might want to put some colored tape between 55-65mm from the bottom of the cable. fluid is checked when is fully hot (car has been driven for about 15-20 min), car is left on, put in park, and check on leveled surface.
