99Z. Read my post again carefully. I didn't say the tranny that came in on it's last leg would be ruined by the flush. Just read carefully. I said that transmissions that are on their last leg are often flushed in the hope that the flush will cure the problem. That just about guarantees that the trans flushing equipement is going to injest a lot of debris from failing transmissions. That debris
could end up in the next transmission that's flushed on that equipment- thus ruining it. That is what the post clearly says. Of course if a tranny comes in on it's last leg the flush did not damage it further but it very well could damage the
next transmission that's flushed on that equipement if the lines are not cleaned carefully and hooked up correctly...
No one knows
what kind of fluid is being used in the flush equipment. That is the point. For a "flush" to be effective there would have to be a
lot of fluid pumped through the tranny. Guys that do the purge method described often go through several gallons of fluid to get the clear, new fluid coming out. Do you really think that the flush equipment is going through that much brand new high quality fluid on each flush? That would be the day...
No, I don't work on transmissions for a living nor do I run flushes. But, I've been involved in the automotive repair industry for several years and have seen a lot of ways that people can fail transmissions - and flushing a perfectly good tranny is a high risk endeavor. I clearly said that not all flushes will result in failure - but that there are significant risks involved in having a tranny flushed. If you want to take them fine, but understand the risks and don't ignore them.
Elwesso. If you can't understand how a tranny flush can ruin a perfectly good tranny then you need to reread my post carefully. You don't believe that stirring up debris in the transmission and flowing it backwards through the valves and orifices in the valve body can cause problems? You don't believe that you could get debris from the previous (failing) transmission that was hooked to the flushing equipment into your tranny causing it to fail? What part don't you understand?
Look at the flushing business logically. The tranny shops and quickie oil change places are out to make money - not look after your car, your engine or your wallet. They will do what it takes to make money. They obviously make more money off of flushes than dropping the pan and doing the service correctly. If they didn't they would drop the pan. This alone should give you a clue. There is a perfectly good reason that flushing a tranny is not in the service manual as the way to service the transmission.
All those transmissions flushes - did you change the filter and such or did you buy into the logic of the flushes that the flush back flows all the stuff out of the filter negating the need to change it? That is some logic! Back flow the crud out of the filter and through the tranny so the flush machine can catch it.
I have personally communicated with 3 owners of Cadillacs over the last few months that took perfectly good transmissions in for a routine "flush" and experienced a transmission failure within the next 5 thousand miles. Not proof, no, but good enough, along with the engineering logic and analysis provided for "me" to never have a transmission flushed. If you disbelieve this do some searches on the net.