Porsche Repair: trans, larry weaver, metal particles

Question
Hello. I have 3 short questions about AUtomatic transmissions. (1). Can a transmission flush harm a transmission? (2). Why do no automatic transmissions have a drain plug like an engine? Only by changing the filter can a portion of the fluid be changed? (3). My car does not go into gear on cold mornings, why not? Thanks. Larry Weaver

Answer
Larry,

A1.  If, by 'transmission flush', you mean replacing the transmission fluid like you change an engine's oil, then this is one of the best things you could do.  A transmission cannot have too new or too clean fluid.  A transmission is probably more dependent on it's fluid than an engine, because the fluid is used for cooling, lubrication and a hydraulic pressure medium.

 I you mean something other than the above, I'll withhold judgement for the time being.

A2.  The automakers don't want anyone changing the fluid without replacing the filter and removing any gunk/metal particles from the bottom of the pan.  Again, clean fluid is a good thing.

Since the filter is swimming in the fluid-filled pan, it's really not possible to get at the filter, or even drop the pan, without having all the old fluid right there.  You'll most likely find it surprising that the filter doesn't hold any fluid, it's really a very fine screen protecting the intake area.

A3..  As for the cold morning problem, it could very well be a linkage binding problem or an internal clutch malfunction.  This is best handled by a transmission specialist.

Please feel free to send me a follow-up question if I can be of any other assistance.

Dave