TCM on 300M

Our 2001 300M is sitting in the shop while we have tried to find a TCM.
Factory is backordered and we bought a used one through the mail to try.
Problem is it looks like it may have been wet, has red rust and white
corrosion on the case, and dealer will charge $150 to install and flash it
before we know whether or not it will work.

I figured if this is a computer part of some kind, it doesn't need to be
wet. The guy that sold us the part says that the outer appearance doesn't
matter. I realize that but the dealer said to be suspicious about it. Would
you spend the $150 to install it if it was your car?

Where does this part mount on the car? If it's on the underside, I guess all
of them could look bad after time.

 

It's normal for the case to have a good bit of white corrosion on it -
that means nothing about its working condition.

It's located right behind the driver's side headlight assembly - just
ahead of the Power Distribution Center and the PCM. It takes 10 minutes
to R&R - two screws - one near the top, on way down at its base towards
the engine. Disconnect the battery (by unbolting main ground/negative
jump post on passenger side strut tower) before de-mating its connector.
I don't know if it's too late, but you could save your $150 and
replace it yourself with no reflash. Why reflash if not needed? That
way, you eliminate the risk of it being bad which you seem to be
concerned about. If it works and shifts fine, you are all set and $150
to the better. Worst-case, the TCM is bad, and you know that right away
after you install it - but my bet is it's good. Anyway, you can find
them all day used for under $50 (www.car-part.com).

Is there a particular reason you are having it reflashed? That's a
waste of money if not needed unless you're determined to have the dealer
put it in and they're including the re-flash for the price. But $150 is
a lot of money for a 10 minute job (of the R&R).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')