Automatic Transmission Fluid pearlescent color

[Roc]

Hi All,
Just winterized the engine and changed the ATF.  I drop the ATF fluid by putting a large aluminum baking pan under the engine to capture it after removing the bottom plug with a 17mm wrench (I've mentioned this method of changing the ATF in other posts).  Usually, the color of the used ATF comes out opaque dark red (as opposed to the clear red when new).  This time, I noticed a 'pearlescent' sheen to the fluid, that looks like it could have fine bits of metal shavings.  My engine has 900 hours and I haven't noticed any issue with the transmission or gears during use.  Has anyone found this to be a normal occurrence with higher engine hours?  What is the consensus for when is the proper time to rebuild the transmission?  Is rebuilding something that's done as part of the maintenance schedule at a certain engine hour amount?

Thanks!! 

[Stu Jackson]

Roc, that could very well simply come from draining the fluid out the bottom, since most of us do it the hard way and take it out of the top. 

Do you still have it?  The old stuff you took out that is.  If so, you might want to take it to an oil analysis place if you can find one near you and see what they say.

I recall Ron writing many years ago about the dangers of doing it that way because, IIRC, there was something to do with the washer compatibility, a "crush washer" that shouldn't be reused.  Might want to check the Knowledgebase on that.

[Ken Juul]

There will be some material removed from the friction disks every time you put the transmission in and out of gear.  I don't think you have anything to worry about unless you start to notice some slippage (engine revs with out corresponding change in thrust).  It is probably more noticable your way because of the large surface area of the roasting pan and you probably to a better job of getting sediment off the bottom of the case.  When removed from the top the old fluid get mixed twice, once being sucked and again when being squirted out (usually into a plastic bottle) so the pearlescent scheen is harder to see.

[Roc]

Stu, you make a good point about bottom draining, but that's how I've been doing it for at least the last few years.  I do have the old fluid and plan on showing it to the head engine mechanic at our marina.  My concern is that since I've drained it this way in the past, it wasn't until this time that I noticed this happen.  I noticed the sediment immediately floating in the aluminum pan, even before I sucked it out and into a clear water bottle. About the crush washer, I bought a bunch of spares, so I always have a new one to use. 

Ken, as I said, do haven't noticed any issue with going in and out of gear and certainly nothing is slipping. 

Thanks for the feedback.
Roc-

[Mike and Joanne Stimmler]

Roc,
Is there any chance that there was some sort of residue on the aluminum baking pan.
BTW, I don't think that 900 hours would be considered a "high hour engine".
Just out of curiousity, how deep is the pan you use? It doesn't look like there is much room under there.

[Roc]

Mike,
Funny you should ask.  That was one of my theories....that maybe there was either a reaction between the ATF with the pan, or some kind of dust on the pan.  I did buy it a a dollar store, but I figured it's used around food, so it should have some measure of cleanliness.

I buy the largest and deepest pan I can find.  Yes, there isn't much room, but what I do is bend it and flare the edges to make it fit.  You have to shove and slide it under the bottom plug.  You do need to contort it, and make room to get your arm and wrench on the plug.  After it's in, then bend the edges up as high as you can (not the area under the plug).  The fluid will run downhill, to where there is more room for the pan at the forward section , and where you can bend the pan edge almost vertical, so it catches the fluid.  After draining, I then carefully slide the pan forward to the deeper section under the engine (to the access door behind the steps) and using a lotion pump, I suck it out of the pan and into an empty water bottle.  Not much capacity of fluid so it will fit into a 16oz water bottle with plenty of room to spare. 

[Stu Jackson]

From a search on "transmission+fluid"

How Much to put back in:  http://c34.org/bbs/index.php/topic,3983.0.html

Flix of old and new:  http://c34.org/bbs/index.php/topic,5139.msg31528.html#msg31528