Transmission Flush, panacea or poison?

[Grif]

Sounds like a "flush" is different than a "drain & refill"...can somebody explain the difference to me?

For the purposes of my original post I was using the terms pretty interchangeably, however some may consider the "backflush" procedure a flush as opposed to a drain and refill. The txmission guy didn't like either idea due to the issues described.

[VX1032]

nothing wrong with doing a drain and refill when there is no previous maintenace history. It won't hurt the tranny. The flush is better, but if you don't know the history don't do it. I flush mine but I have been doing that since I got it at 29K. It has been flushed 3 times and only havs 54k on it now, a little excessive, but I know the history.

With a flush you disconnect the trans line to the cooler, and hook it up to a michine that pushes the fluid under pressure through the entire system. AT that point you can see the change in tranny fluid in the machine as the fluid changes color from the black that it is to the red of the new fluid. Typically the flush takes a tad more fluid than the specs for the trans due to the overlap in fluid.

A drain and refill, is just that. You drain the fluid out of the trans and then refill it. All the fluid is not taken out because of the fluid in the lines and residual in the tranny. Since there is no pressure, the risk of taking anything out that has been varnished on is limited and you should not get the chunks floating around in the valve body.

You need to change the fluid on our trannys due to the breakdown of the fluid, escpcially with the heat our trannys can generate, and heat kills.

If the flush isn't done every 30K, I would never do one, drain and refills are fine.