Flushing my own transmission

[juju0990]

I have a question about flushing the transmission on my Q45, now from what i have read about how most flush machines is they work by using the trannys own pump to basically exchange the old fluid with new fluid. Cant I just buy 6 foot of the correct diameter hose, disconect the return line from the radiator hook up that hose let it dump into a oil drain pan. Start the car stick in the funnel and fill the transmission as fast as it will fill and wait for the fluid to change colors. Is this as good as a flush machine ?

[Q451990]

Good question... I'm not sure if the return path from the cooler is the same as the fill tube - so you could be starving the transmission of fluid this way. One way to do it is start the car... run 2qts. out, then top off, then repeat. It's not as good as a real flush, but better than nothing at all.

I once rigged up a 5 Gallon bucket with a hose coming out of it to attach to the input line of the transmission only to discover that the pump only "pushes" fluid, but doesn't suck it back in through the input...

Heath

[Q45tech]

The return line feed the rear planetary gears first then a few other areas before it returns to the pan [where the filler tube flows to].

You might end up doing more damage than good with your method.

[DAEDALUS]

The 5-gallon bucket method ought to work fine if you elevate it just enough to provide the right flow rate through a spigot and hose. You would have to experiment a little to get the right height. Should move a quart every 15-20 seconds or so.

[juju0990]

OK thanks guys, I guess because it would not be a constant loop maybe it not to safe to try. Thanks for the input !

[Q451990]

The 5-gallon bucket method ought to work fine if you elevate it just enough to provide the right flow rate through a spigot and hose. You would have to experiment a little to get the right height. Should move a quart every 15-20 seconds or so.

I thought of that, but the pump really pushes that fluid out fast! I'm not sure that gravity feed without a really large hose, and then you'd still have to reduce it going back into the tube.

Heath

[Q45tech]

But you still are not feeding the rear planetary as the only way it gets lubrication is from the 20- 25 psi pressure on the rad return line.

[DAEDALUS]

Ahhhh...so get a sealed metal container and pressurize it with shop air! With all these little complications, I'm starting to wonder how the transmission flush machines actually work.

[juju0990]

I wonder too, so Q45tech the fluid is only being pushed through the trans by the trans pump ? So with all that said is a Pump inlet flush machine safe ? From what I have read this method does a better job than cooler flush machines.

[Q45tech]

The BG machine has a rubber bladder with a floppy internal rubber membrane.......that costs thousands of dollars. The 14 quarts fills the bladder and every quart that the transmission pumps in, an exact corresponding amount of new ATF is sent into the return line.

There are shunt valves and inlet and outlet pressure gauges, pressure relief valves, drain valves, etc, etc .

You only need a PHD to work it properly. The secrets are not in the 1 hour training video tape.

Many transmission just dump the return line into the pan, Nissan does NOT that is the problem.

[AZhitman]

That settles it - I'm paying for a flush the RIGHT way.

[maxnix]

Paying is cheaper than improvising a disaster.

These are not Rube Goldberg machines, at least speaking for the Sun and BG ones I have seen operate.