Originally Posted by duxthe1

The trans shift and climate issues are probably do to a vacuum line(s) off at the lower part of the intake at the back of the engine near the crank sensor There are coolant connections at the rear of the engine, too, but they don't give trouble often. Grab a flashlight and pop your hood open. Leaning over the driver's side fender find your heater hose and follow it down to the engine. Check the hose for leaks and inspect the area under the fitting for leaks too. If everything there looks dry peek down beside the dip-stick to see if the block is wet down there behind the water pump. Water pump leaks are real common on the M104