Tempted to drain trans

[marquisboi]

I have a 138K mile GMQ and I'm not sure if the trans was ever serviced. I don't see any records for it, but who knows. The fluid looks tired, not bright red, some clutch material, likely not burnt.

Shifting is 8.5/10 knowing these cars. But after doing the intake things improved, so the small issues may be misfire related (very common issue for these fords).

I know I'm not going to flush it - so I have two options.

I already have a filter...

Pan and filter drop, of course that replaces less than 1/2 the fluid.....

T/C drain + pan drop.

Then there are always the old wives tales about putting in new trans fluid and bricking the car.... A used car dealer I knew said that if the fluid isn't burnt (then just leave it) do a pan drop and filter and then in a year or so do a full drain. He said all new fluid with unknown history is a bad idea. He said he sold tons of rwd fords and rarely had issue.

[IPreferDIY]

I recently did a tranny fluid change after discovering the torque converter drain while doing other stuff. I read lots of stuff beforehand, and my view is that changing the fluid can never be a bad thing.

One comment that I saw was that lots of people only change the fluid after a problem has surfaced, and that's why you hear so many people say their tranny died after changing the fluid.

My own method for 'refreshing' the fluid has been to stick a tube down the dipstick tube and use a hand pump to suck out what I can. I can get about four liters if the rear driver's side corner of the vehicle is jacked up a bit to angle the pan forward. This is about as much fluid as you would get by dropping the pan, but without the hassle. Just make sure the tube is clean so that you aren't introducing contaminants.

I generally don't bother with the filter. The first one I changed (on a Hyundai Stellar) was merely a screen that had no contamination whatsoever, and ever since I have considered changing the filter to be a waste of time. I've read that even Ford recommends not bothering to change the tranny filter. I appreciate that not all tranny filters are merely screens, and I wholeheartedly concede that dropping the pan provides the advantage of visually inspecting things and perhaps checking the torque on the valve body bolts. But, as I understand it, the detergents in the tranny fluid keep most of the contaminants suspended, and that's what you want to get rid of. If your transmission is at the point of shedding chunks that need to be caught in a filter, it seems to me that longevity is no longer an issue.

I remember seeing someone ask about what happens if you mistakenly use Mercon when you were supposed to use Mercon V, so I will note that I did this the first time on my 2000 Grand Marquis LS, and I did not have any obvious problems. Of course, replacing all 13 liters with only Mercon compatible fluid would be a concern. This is something that might happen if you take it to a place that uses generic fluid for flushes.

When I drained the torque converter recently, I got at least five liters out of it, so a total of about nine liters out of 13. Some people take steps to get the fluid in the cooler, but I can't be bothered. Nine out of 13 is about 70% fresh, which is a lot better than what it had over the past several years.

One issue that concerned me was starting my car with an empty torque converter. Just to be on the safe side, I cranked it over once or twice with the fuel pump disabled (you whack the fuel safety switch in the trunk to kill the pump) to introduce some fresh fluid, and then I started it properly. I didn't have any issues. I doubt they would have put a drain in the torque converter if starting it empty after draining would cause problems.

Just my $0.02CDN.

[gadget73]

I figure if it dies when the fluid gets changed, it was already dead and just hadn't quite realized it yet.


Get the filter because it comes with the pan gasket. Its not an amazing filter, but you want the gasket so you may as well do the filter while you're in there. Its a bit more than just a screen on these cars.

[IPreferDIY]

Minor correction. I should have said "about five liters" rather than "at least five liters" from the torque converter. I also forgot to note that I put about five liters in the pan before initial start-up and then turned off the engine after about 10-20 seconds so that I could put more fluid in the pan after the torque converter filled up. Running the engine any longer after initial start-up would have presumably created a risk of the pump running dry. Putting all nine liters in the pan before initial start-up would have presumably created a risk of making a tranny fluid milkshake during initial start-up.

[marquisboi]

I figure if it dies when the fluid gets changed, it was already dead and just hadn't quite realized it yet.


Get the filter because it comes with the pan gasket. Its not an amazing filter, but you want the gasket so you may as well do the filter while you're in there. Its a bit more than just a screen on these cars.

I have a filter, just have to decide if I want to do the T/C drain. I asked another local trans guy(the owner) and he said pan drop is enough, you just want to renew additives in the fluid. He said the mechanic in a bottle crap is less than a quart and is supposed to do miracles. Then he said its your money. He personally drives a crown vic and said he installed a drain plug and dumps the pan every 21K miles, filter every 4th dump. He said take the money for the extra quarts and buy a good cooler. He looked at my fluid and said whatever you do the chances of failure are very slim, and would happen whether the fluid is changed or not. He did advise 100% against any chemical or pressure flushes. He has a simple T-Tech machine which just does an exchange, but he said he always changes filters first.

Also, These are different from the box bodies:
1) The stock gasket is 100% reusable, it even says it on the gasket package!!!
2) The screen is a dacron/sponge, not a metal screen. http://www.filtranllc.com/products/auto_OE.asp
3) They have no bolts holding the filter in. It isn't an impossibility to see a filter floating in the fluid if it was installed improperly.

[gadget73]

You may as well drain the converter. No point in doing half the job. Thats like changing only half of the oil in the engine.


and you didn't say what year car you have, so I just guess at it from what I know, which is boxes.