So , is there any downside to just using the return hose to refill instead of taking the side plug out?
Just seems like less hassle and it's right there when you set up your catch bucket.
None that I know of. It is where ATF exchange machine hook in.
Will new fluid just flow in via a funnel or does it need to be pumped in.
I've never tried using just a funnel, to pour into ATF cooler return hose. My guess, it would flow.
I'll give it a try, after draining pan. I'll pour in 1 qt., measuring what comes out of pan's drain plug, as I do.
So I did try, just pouring ATF into return hose, this last week. Via a ATF funnel adapted to return hose. It was too slow. You may have different results!
Here's how I ran the gravity fill test:
I empty AT pan first, letting pan drain for ~45 minutes. Getting 3.5qt out of a 1999 LX. (It was still dripping a bit)
I did not put drain plug back in, for the test.
I then poured ~0.2 qt, clean fluid in funnel attached to return hose (engine off).
~0.2 qt came out pan, about a fast as went in. It was, a bit dirty. Likely picking up some old ATF from return hose, path into AT pan and bottom of pan. I did not use more clean fluid. As would have left me short of fluid for my flush. It also went slow enough, I knew what I wanted to know. So had no need to waste more.
I used a few different sizes of clear hose, to adapt return hose ID to my ATF funnel. The hose used first, was only 4" long. It was the same size clear hose, I run to 2 gallon catch bucket (Seen in: pictures in post #1).
It difficult to say, how much if any. The smallest adapt hose, may have slowed the fill. I don't think it was holding back the fluid flow into return line. I would have to make, a thinner walled adapter. Perhaps a thin wall metal pipe, to see if gravity feed though larger ID adapter hose, makes any difference in flow rate.
The set-up I have seen work. Uses a pump, to pump into return hose:
I'd want a 3 gallon vessel pump. Where output is controllable, by flow amount and pressure. Using no more flow or pressure, then AT is pumps out.
The range of pumps, runs from a hand pump to a fluid exchange machine.
We'd not want any more flow or pressure, than that of AT fluid cooler system operates at.
Other consideration are:
- Space: 5' of clear hose, take almost no storage space. Pump or exchange machine, take a great deal more storage space.
Cost:
- 5' of hose is ~$5 and readily available at hardware store.
- Pumps: $100 to $500, not readily available.
- Exchange machine, using vehicle ATF pump to control flow and pressure. $1,000 to $5,000.
- How often used to justify time and cost.
I dream of storage room for
