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Old 04-13-2010, 12:30 PM
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Quote:
Originally Posted by sunny5280 View Post
From my second post on this subject I clearly said:

"There is the possibility of dislodging sediment but even if that were the case I have seen no evidence to support that dislodged sediment correlates to transmission failure....."

"I previously acknowledged the possibility of disloding sediment....... Furthermore should sediment be dislodged I have seen no evidence it will result in a transmission failure.
You've got it backwards. The only way you would know sediment was dislodged, and that it mattered at all, is when you do have a transmission failure. You are saying that there can be sediment moved, but so what? I am saying that the failure analyis of any failed transmission provides the type of proof you are looking for. Think about the valve body located in the pan of the transmission. It contains very small orfices, check valves, and control circuits. The failure analysis of a transmission that didn't shift properly (after a fluid change) has been found on too many occasions to include that famous sediment in the valve body, restricting a passageway. It isn't that sediment might get dislodged, and not hurt anything. We wouldn't even know if that happened. It is that if you analyze a failed transmission, and check which clutch pack or actuator stopped working, and then search for and find debris in that circuit that you can conclude that something caused the debris to move.

The photo attached isn't a ZF, but it will do. There is a spool valve at the top left, and there are multiple check valves (ball bearings with springs). The passageways are about the size of a pencil lead. Also, the fluid is somewhat static, so what gets stuck doesn't get flushed out easily.

Sorry, that is the best I can do for an explanation. Photo attached.
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