Brown fluid! How many drain and refills?

[The Critic]

Found the ATF in my dad's 92 Previa to be dark brown, equivalent to used motor oil, minus the odor. Mileage is 65k, vehicle is used only for highway driving.

Factory fill is Dexron-II, though one drain and refill with Chevron Dexron-IIIH was done @ 45k miles. The unit holds 6 qt, a drain and refill removes 2.5. There's a fine screen filter inside the pan.

How many drain and refills will it take me to restore this fluid to a "normal" appearance? Should I pull the pan to replace the pan gasket, clean the magnets, and replace the screen to transmission gasket?

Thanks.

 

[sw99]

You may want to have a good slow flush done. That way your getting everything out. Then I would install a drain plug and just keep up with the partial "pan" drains every few OCI's.

 

[ConfederateTyrant]

Try three drain and refills, and on the final one, remove the pan, replace the gasket, clean the magnets and replace the transmission screen filter. After that, drive it for 10,000 miles and do a full flush and replace the filter again. From then on follow up with a normal flush every 30,000 miles or one drain and refill every 10,000 miles.

 

[Steelers]

Three should do the trick. Drive a week or so between drain and fills or take the car for a long drive. Once the fluid looks good start a drain and fill regime every 10-15K to keep it fresh. Any Dex III ATF should be fine.

 

[Pablo]

Just buy a case of low cost ATF and keep doing the drain and refill - probably 3 OR 4 times as the fellows state.

Then change over to synthetic and forget about it.

 

[Mike_dup1]

Or else you can take it to a trans shop and have them purge the trans for you. I have seen them do that on vehicles with bad fluid. They just keep purging it till it comes clean and not by using a machine either.

This way, you do it once and be done with rather than spending all your time changing the ATF. Also they will be able to appraise your situation and advise you if you have problems.

 

[unDummy]

Vehicle maintenance can be costly. Some people have time. Others have money. A flush costing >$100 vs a $10 drain/refill 3-5 times is for the owner to decide. And, finding a competent shop to trust is difficult these days.

If you have a drain plug, do a drain refill every 1k-2k miles until the old fluid, leaving the transmission, is the same color as the ATF you are adding.

Servicing the pan magnet/filter should be considered but can be pushed to 100k if you don't want to make that investment yet.

Start a yearly drain/refill after the initial fluid regime.

There is nothing wrong with using a flush machine. Most are nothing but valved sumps that use old fluid to push in new fluid via displacement. I just find that the cost is excessive especially if someone has some tools, time, and doesn't mind doing their own maintenance.

 

[The Critic]

I think I'll pull the pan, clean the magnets, replace the filter screen, as well as the filter gasket and pan gaskets, followed by a refill of SuperTech Dexron-IIIH. Then I'll drive around for a week, and continue to do drain and refills until the fluid looks OK. The pan already has a plug in it.

 

[Big Jim]

You can do a flush yourself. The hose in a bucket method. I'll review it in case you have not seen it posted before.

Find a 5 galon plastic bucket. It halps to calibrate it so you can easily tell how many quarts you have puumped out. Calibrate it by adding a quart of water to the bucket one qluart at a time and marking the bucket. Use a quart canning jar filled to the brim. For that car you will probably want to mark it up to about 12 quarts with the anticipation of using 9 or 10.

Find the trans cooler lines to the radiator. Have someone tickle the ignition with one of them disconnected to determine an outflow line. Determine the ID of the hose. Buy about 6' of clear plastic hose on the same size from a local hardware store (the stuff is cheap).

Slip one end of the hose over the fitting on the car and the other end into the bucket. Pull the transmission dipstick and insert a trans funnell. Find an assistant. Have the assistant start the car while you add fluid at about the same rate as what is going into the bucket. If it gets ahead of you (and two or three quarts won't hurt) have your assistant shut the engine off while you catch up.

Continue until the fluid coming out is as pristine as the fluid going in. How much that takes depends on how dirty it was to start with. Usually that 1 or 2 quarts above the transmission normal capacity. A really dirty trans make take 1 1/2 or 2 times normal capacity.

Restore the trans lines, warm up the fluid, check the fluid level, and you should be good to go.

This method absolutely works. It is used in many repair shops, including dealerships.

If you feel that you must clean the screen (or change filter on some cars that have media filters) or clean the magnets, drop the pan and do it first tnd then flush. This type of flush minimizes the need to do either.

 

[The Critic]

Thanks. I think I might just do the full flush method in addition to dropping the pan, changing the filter + gaskets, and installing an in-line magnefine filter.

Anyone know what size my tubing might be? 5/16" or 3/8"? How much do I need to cut?