Speaking as a minor authority on transmission fluid changes,etc. All the tranny flush machines I have seen divert the old oil that was going to the oil cooler into a bladder seperated reservoir. That old oil forces new oil from the opther side of the bladder throughthe oil cooler and back into the tranny--just like normal flow. It takes about 2 times the tranny oil capacity in new oil to get it really clean. Then you can drop the pan and change filter, fill pan with new oil (4 qts?) and b ehappy. The machined do not force oil back through the filter ,etc. They will not 'cure' a mechanically sick tranny, nor will they damage a good one.

Engine flush machines are totally different and I cannot recomend any of them. Risk of dislodging abrasive 'coffee grounds sludge' into precision bearing surfaces is high. Use the STP engine flush per directions to remove sludge and varnish. Add 1 pint of Marvel Mystery Oil to the crankcase with every change instead of the last pint of oil. It slowly removes the clear/amber lacquer without causing it to spall andclog oil passages.

That's because most manufacturers don't provide a torque convertor drain, and MB does. No need to "flush" the torque converter when you can simply drain the fluid.

Flushing the engine with anything other than fresh lubricating oil will cause far more trouble than the non-existant "sludge" (you shouldn't have any if the engine is properly maintained -- if not a "flush" won't help much in any case!).

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!