Auto trans goes into neutral at a stop.

[Dad]

2005 4.0 auto. I got a bright idea to change the trans fluid and filter a couple weeks ago. In hindsight I do not recommend this. It seems to shift better when cold, but after it gets warmed up it will slide into neutral when I come to a stop. Not every time, but often enough that it is annoying. Usually it is after a fairly firm stop rather than a gradual stop. Like it is not downshifting correctly. Have to rev it a bit to get it to go back into drive. The last couple days when this happens the engine will stall. I have no idea what is going on. No warning lights, no codes. I used Merc V fluid.

 

[07gts197]

How much fluid did you use? And did you also drain the torque converter? Sounds like its low on fluid.


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[Dad]

I drained the pan only. A little under 4 quarts. I added back almost exactly the same amount. My thinking was low fluid as well, but it is such a pain to add it. Whose idea was it to have no dipstick to check the fluid?

 

[Pentalab]

I added the PA deeper pan on my 2010 GT auto ( 5R5SS)..which now uses an extra 4 qts. It also comes with a locking style dipstick, next to battery, on the firewall. Big enough to also add ATF if required. Deeper pan also comes with a drain plug. To change ATF, you really need to drain the tq converter as well. I used RP max ATF synthetic.

One thing I did notice, was when stone cold, the ATF is higher on the dipstick..... and drops a bunch when tranny heats up.

The oem setup to check / change atf is goofy at best.

I'm 99% convinced you are low on ATF.

In my case, I also add a JDM engineering catch can to the 5r55s, so it won't puke atf all over the ground. Without the dipstick, you have no clue how much atf is actually in there. I also added a 2nd auto tranny cooler, in series with the oem tranny cooler... ( made by B+M, 13 K btu).

To get all the atf out, local ford dealer applied air pressure at the 2nd tranny cooler....and a vac on the other leg. Then it all comes out.

Even then, I had to tweak the ATF level...such that level was normal..... but only when up to normal max temp, which is 170 deg F..as indicated on my aeroforce digital gauges plugged into obd port. Stone cold, the level reads way higher than the high line. Before that extra atf added, it was shifting a bit strange, once warmed up. I had to add an extra 1-2 qts. You could also have some air in there some where.

 

[05stroker]

It's been a long time since I had the 5r in mine but I seem to remember when I changed it I would overfill it get it up to temperature then take the little center bolt out of the drain plug and let it drain until it was just a trickle

 

[Dad]

It's been a long time since I had the 5r in mine but I seem to remember when I changed it I would overfill it get it up to temperature then take the little center bolt out of the drain plug and let it drain until it was just a trickle

I think this will be my plan. However I will have to get more IN before I can do this. I presume I can use a turkey baster or something to squirt ATF into the center of the drain plug?

 

[Dad]

After having a moment of stupidity this is resolved. Bought a $10 fill pump and put a couple quarts in. The stupidity was forgetting the car needs to be running at normal temp BEFORE removing the dang fill plug.

 

[Pentalab]

With eng in idle, sitting in driveway, auto tranny will eventually get up to aprx 120 deg F. Out on the road, (with a load on it of course).... it will eventually get up to 170 deg F.