rdubious23

Okay, so my personal mechanic just did some trans fluid service, switching out 2 qts. He suggested a full flush. I called Toyota and they're saying NOT to do a full flush because you'll lose the metal shavings that have accumulated over the years (93 SC400)and begin causing the the trans to flush. Is this accrate? Reading through the threads and what I thought I knew, I thought the shavings will jack up the transmission even more?
Toyota said they NEVER flush?

trancuongv

iTrader: (3)

Shavings inside the tranny or motor is never good. I would call a different dealership and ask. If I had a automatic tranny I would flush the tranny.

TLDriver

iTrader: (4)

Well when you say "flush" do you mean flush or drain and fill? Drain and fill is what I would do. I would never do a flush on the transmission and a lot of dealers/mechanics will stay away from that route. It's more profit usually but can be pretty hard on the transmission at times.
What I would do:
Drain Transmission fluid, change out the transmission filter, and refill the transmission.

rdubious23

So I just called another dealer as suggested, and they confirm that they don't do a flush, just the drain and fill. $80, said they get about 75% of the old stuff out of there. Made a good point saying that a complete flush COULD be a shock to the trans and another service in 15K would be a good thing. That sounds reasonable to me, not the "shavings are good for the trans" statement the earlier dealer said. The shaving should accumulate on the magnet at the bottom, right?

thanks for everyone's input so far.

Lexmex

The word shock is right on point.

The only time I did a flush was once when I had silvery pinkish fluid. I changed out the fluid once on drain and fill, found no shavings, but realized I was bound go to through several drain and fills to remove this stuff, so in that case I did a flush, but when you got shavings in the pan you want to take it very easy and remove that stuff over time with drain and fills. I usually do 3 drain and fills over the course of 3 weeks and on the last drain and fill I will change out the filter.

Not all shavings go into the pan. Some can get lodged in the valve body and necessitate a minor overhaul, but you'd know something was amiss after changing out your tranny pan and fluid if you still have issues.

The first picture is from the tranny pan on my RX300, that is acceptable as some sediment can get on the magnets.

The second photo (look at the 3 magnets in back) is from a U140F tranny like the one in my RX300, but actually one out of Rav4 (which in some models used the same tranny). Notice the big chunks on that magnet. That tranny got destroyed and of course this is unacceptable.

On a side point, many years ago I heard this comment about the shavings are good, something to the extent about friction, but I've never been able to locate any information that supports this and concluded it must be garbage.

TLDriver

iTrader: (4)

That's what the BMW dealership told me too, and mine even had that wonderful sticker on the transmission. Just because I had done my research it came out being that my 528i did run a GM transmission. I would just wonder why replacing a used filter would be a bad thing?

stockhatch

iTrader: (12)

There is some truth to the flush being a bad idea on a high mile trans that is not in great shape. The fluid over time has accumulated some of the abrasives off of the friction disks, and when you flush the ailing trans, you essentially flush the friction disk material out with the old fluid.

Many high mile, previously neglected autos will begin to slip shortly or immediately after a flush. I have had trans shops refuse to flush older cars I had due to the high possibility of slipping afterward.

If you maintain and flush your trans at the recommended intervals, you shouldn't have this problem, because clean fluid wont strip the abrasives off of the disks to begin with.

Gspec

Best thing you can do when servicing a high mileage transmission is to jack the drive wheels off the ground, and run the transmission in reverse for a little bit...on the majority of trannys this will dump fluid back into the pan bypassing normal drive channels and put most of the debris where you want it (on the business side of the filter)

The amount of debris in those pics doesn't look like anything to fret about....I've seen alot worse come through the shop for normal service and the owners never mentioned any shifting problems...

expansive

good thread. I was searching around for a thread with some good info on Tranny fluid and this one helped alot