Wagon Transmission Fluid change

[Sarthos]

Okay, I just got a cb9 with 92k miles on the odometer. Unknown actual miles, the odometer's broken. Anyway, I need it to last at least until I can get a 5 speed swap done, and my dad thinks the transmission fluid smells funny. Unfortunately he is paranoid bordering on schizophrenia, so he'd think it smelt burnt if the fluid were two minutes old.

Anyway, drain and replace the fluid, drain and replace fluid with a filter change, or flush the fluid, and change the filter? I've heard flushing the fluid can be really bad for your transmission if it hasn't been done regularly, but draining and filling isn't as bad. Something about flushing the fluid causing stuff to fall apart or get released into the system...not sure. Thoughts, opinions?

[Fleetw00d]

There is no filter, so that's out. What color is the fluid? Should be a fairly bright red; if it is tending toward golden brown, it's cooked. A single draing and replace removes about 2.5 quarts of the 6 in the transmission leaving about 60% old fluid. If after the first drain and fill, you drive it briefly, and do another drain and refill, you will be left with about 34% old fluid. Repeat it one more time, 20% old fluid. Most complete change would be accomplished by a transmission shop that can tie into the cooler lines and remove old fluid from one as they fill with new through the other. I don't think either method would be harmful.

[Sarthos]

Actually there is some kind of filter element up inside the transmission, but it's no fun to replace apparently.

There's 6 quarts in the transmission? I thought it was only 2.5 total?

[deevergote]

Essentially, the filter is not replacable. Best to just treat it that way.


If you don't know when the last time it was changed was, assume it was NEVER changed, as this is very often the case. Use Honda ATF, and nothing else.

Flushing the system can indeed wash out any gunk that may be clogging leaks, or keeping certain components from slipping. Flushing is a bad idea when such gunk may be present, because it will make problems that already exist more prevalent. Flushing itself is not bad... but when you don't intend to rebuild the transmission, you might want to make use of that gunk that may be hiding problems.

[Sarthos]

That's sorta what I thought. It can also kill an engine in similar ways if you flush the coolant or oil wrong I've heard. If it's done regularly though (like if you flush tranny fluid every 20k miles) doesn't flushing help a transmission live longer? And yes, I will use Honda ATF.

[Fleetw00d]

Actually there is some kind of filter element up inside the transmission, but it's no fun to replace apparently.

There's 6 quarts in the transmission? I thought it was only 2.5 total?

Honda manual says 2.5 quarts at oil change, 6.3 quarts at overhaul (a lot of fluid stays in the torque converter).

Manual transmission is 2.0 quarts at oil change, 2.1 quarts at overhaul.