Hey guys, I've got an EL Fairmont Ghia which is doing some odd shifting down to 1st gear in D.

It only does it when the car is warm, it will go to downshift to 1st gear when coming to a stop, the engine revs go to under 500 RPM, it goes to stall and then revs up to 1500 RPM and shifts into first with a clunk.

I'd like to flush the trans, I'm thinking of removing the outlet pipe of the trans cooler on the side of the radiator, would that pump all 9 litres out of the box?

I want to put about 20L of normal ATF through it, then drain it all out again then fill her with full synthetic ATF, maybe it will fix my problem?

I replaced the map sensor and ISCV with new non genuine ones, then it started acting up, co-incidence?

Thanks much.

do a filter change first. top up to level, then remove the outlet hose and start engine. But make sure the auto never runs dry. You'll probably use about 20L of fluid if the auto fluid in it is black

The top ATF outlet on the radiator is where the fluid will come out.....not the pipe that screws into it.