Auto fluid change, push old fluid out

[Snoman002]

Changing the fluid on our '19 Highlander.

Can I use an external pump to force new fluid through the filter path to push out the old fluid in the converter and cooler?

Edit: To expand on this. Was planning on a drop and fill, figured there might be a way to push more of the old fluid out while I'm in there.

 

[Dave1027]

I'm assuming you are posting about the transmission fluid? I recently did this on our 2018 4runner. Disconnected the line at the radiator cooler. Ascertained which line was outflow and inflow. Used a generic 1 gallon sprayer connected to the inflow. Ran the outflow into an empty jug. Had helper start engine to pump out 1/2 gallon. Then pumped in 1/2 gallon of fresh fluid. Repeat 6 times to replace all 3 gallons of fluid.

 

[Vil_Riker]

I wouldn't push anything - just drain and fill.

 

[supton]

Not sure I would. I'd rather drain and fill, then pull a cooler line, start the engine and let the engine pump out one quart, shut down. Refill. Lather rinse repeat until fluid comes out clean, or x quarts is cycled through (x being whatever magical number you want).

Thing is, on my Tundra, it had a thermostat on the side of the transmission. If the fluid was not warm enough, it would not pump to the large ATF cooler. But it could be defeated with a cotter pin--push in the button, slide the pin in, and then it would be on full cooling mode. Zero knowledge about yours, maybe if you can find a parts diagram you can find out if you have the same thing.

You might find a coolant-heat exchanger instead on the side of the trans, with no traditional ATF cooler (I think that was the base setup on my Tundra, if not tow equipped), that could be made to work somehow, but it may also be a lot harder to get to. YMMV.

 

[Snoman002]

Generally not a fan of the start and pump routine. The few times I have tried it had transmission fluid coming out at a tremendous rate, far faster than I could reasonable manage. I think I pumped out like half a gallon before I could get the key turned off. I really want to avoid running the pickup dry.

Looking at this setup and it's a bit different. It's a transverse mount with the pan on the side. Pretty tight spaces. I would just do a fluid drop and refill but from what I have seen that gets less than half the fluid out.

This also means it runs a weird filter that bolts in with a gasket, not the typical tube and oring setup. That makes it much harder to rig a connection.