I keep hearing that tranny flushes are bad. Why?? Ian your thoughts on the
matter please.
Thanks,
Glenn
> I keep hearing that tranny flushes are bad. Why?? Ian your thoughts
> on the matter please.
I suppose it all depends on the definition of a trans "flush". If this
means that shop is using some sort of machine that forces clean
trans fluid thru a transmission at some high pressure and possibly
in the reverse direction of normal flow....then I'd probably agree.
I've never seen a machine that does that, but of course, that doesn't
mean they don't exist.
On the other hand, if what is meant is a machine that simply attaches
to the trans cooler lines in series and while the old fluid runs out one
cooler line, new fluid is pumped into the transmission at the exact
pressure that the transmission normally uses at the cooler lines, (in
other words, a simple fluid exchange) then I don't agree that a
trans "flush" is "bad". Probably because I've used the above
type of machine for about 5 years now on a regular basis and have
never seen any ill effects. I've used it on my own vehicles, works
quite well. Especially if you pump about 5 litres more fluid then
the capacity of trans thru it...you are pretty much guaranteed that
there is no old fluid left in the trans.
I think two things might make people nervous about the trans
"flush". One, it's seen as a profit center for shops...and this
is very true. Easy money. Gee, I wonder why it was developed?
I mean, everyone knows that automotive repair businesses are
certainly not in "it" for the money...right? The other possibility is
that people will forget to do the regular old trans service which
involves dropping the pan, checking for debris, and changing the
filter. Personally, I believe that most trans shops would actually
prefer to drop the pan. I mean, you can show the customer any
amount of what really is normal debris, spin a tale of how bad
it looks in there, and get an overhaul out of the deal. Keeps you
busy in the slow times.
We do both. We usually alternate, first a fluid "exchange" at
that specified mileage, and then the trans service at the next
specified mileage. Eventually, or if the fluid is particularly dirty,
we can/will combine the two procedures.
Ian