Q: autos and torque converters

[barf]

at the risk of sounding naive i'd like to ask what the deal is with properly replacing fluid in auto transmissions and torque converters.

i've rebuilt my engine and am dying to turn the key but want to be sure i'm not going to damage anything carelessly

the mitsubishi parts guy tried scaring us into paying for a professional fluid replacement service when we picked up the filter, what is that exactly and does the transmission pump fluid into the torque converter or what?

[KKtrips]

Did you drain the trans oil when you pulled the engine out?

I would just make sure the trans has approx the right amount of oil in it and run the engine in (checking the trans level as one of the checks while you are running in the engine)

Don't be too concerned with the trans as you can't do much damage to a trans by running low oil in it as long as you are not driving the car.

Once you have the engine sorted drain the trans oil and replace it or take it to a workshop who has a trans flushing machine and get them to flush your trans for you (most Pitstop/Midas stores have this sort of machine)

[keltik]

The sump/pan only holds around 2 to 4 liters of ATF. The rest (4ish liters?) stays in the torque converter and valve body so the "only" way to change all of the fluid is with a fancy flush machine.

One semi useful way of doing a full fluid change yourself is to drain the oil, refill, drive 10mile, repeat. After 2 fills and drains - the oil left in the torque converter and valve body will be mostly clean.

[DavidTheCreator]

as my boss used to say, old coolant mixed with new coolant doesnt make new coolant

suspect that theory is tru for atf aswell

i would just chuck the same amount of new atf in as the old atf that came out.

and make sure you have the right shit

check here if your unsure http://www.castrol.com/castrol/genericsection.do?categoryId=8290000&contentId=6007486

click on lube guide

[D_LOOM]

Basically you hook the transserve machine up to the trans cooler lines, fill the machine with however many litres it takes and it will flush the old oil out, flush the cooler and torque converter at the same time. The level will have to be correct to start with though as it only replaces what you put in eg 6 litres in, 6 litres out.

Check the level with the engine running in P or N. The pump will fill the converter.

Dropping the pan (to replace filter etc) and depending on transmission size will only give you about 3- 3.5 litres out of 7,8,9 litre systems

Can you get a trans model code? if so i can find out at work how much oil it will take.

[barf]

thanks for the replies!

it was drained and transmission is a W4A51 (4WD transmission on CM5A)

if you could confirm the amount of fluid that would be choice. I can't find the service manual for this transmission.

[KKtrips]

Looking at the closest thing which is a 93 Lancer with a 3spd auto I find

AUTOMATIC TRANSMISSION

CASTROL TQ-DIII

Service Refill Capacity: 6.1 Litres.

See note 12 below.

NOTES

12 - Dry fill capacity shown, fill only to full mark

It would be close to this.. But if you have some in there already I would chuck in 3 litres then dip it once you have it running.

/ask on a Mitsubishi website cos I have no idea on late model stuff..

[D_LOOM]

Hey, how'd you drain it?

Does it have the spin on filter on top of the trans?

Takes about 7.8L dry fill

[barf]

Drained it by removing the drain plug/bolt

Yes, it's similar in shape to a typical oil filter

and thanks it's running good and shifting smoothly now

[D_LOOM]

Sweet, good to hear.

There's another filter in the trans but you can't get to that one unless you overhaul it.