Transmission flush

[HiTek21]

I did a transmission flush on my Legend few months ago. I didn't do a power flush because the people on the legend forum said it would do more harm than good. So I followed a DIY from a Transmission Mechanic.

Dumped the fluid and put F-Type tranny fluid drove it around for several miles then dumped it, put Dextron Fluid (same method twice), finally some Honda Fluid (along with something called lube gard)

Didn't really see all that much difference before and after, it does shift a little bit smoother from 1st -> 2nd gear.

 

[Calin]

Originally posted by: Quixfire
Roger told me why he left and I don't have his permission to share that information publicly yet. I hope to talk with him by this weekend and ask him if it's ok to post then.

Thanks for you patience,
Quixfire

That's so sad for the ones that remain here. Roger was like a kind of car guru or something. Almost every post he made teached me something new.
I hope in his return

Calin

 

[Pacfanweb]

1. There are quite a few knowledgeable mechanics on ATOT. They don't necessarily post in every single car thread, or act like their word is the gospel and nobody is allowed to prove them wrong or have different information like a few I've seen do here.

2. Some tranny flush machines only use the pressure from the transmission's own pump, so there is no worry about some external pump breaking loose a bunch of sediment from sheer pressure.

3. Ask most any mechanic and they'll tell you it's not good to flush or otherwise change the fluid in a high-mileage tranny......IF the fluid has never been changed or it's been a very long time since the last change.
If you have a high mileage vehicle and you've been flushing you trans regularly every 30k or whatever your particular car calls for, keep right on flushing, you aren't going to hurt a thing.

Now why shouldn't you change the fluid in our particular scenario? Some of the reasons have already been mentioned, but I haven't seen this one: If you change that high mileage fluid, you will drastically change the viscosity of what the trans has been running on for all those miles.....what all that transmission's wear and shift characteristics have been based on.
With all that cluch material mixed in, that old fluid is much thicker than what you're going to replace it with, and that affects hydraulic pressure which in turn affects how the tranny shifts.

4. In the end, you have to go with experience. Mine includes 15+ years in one of the largest dealership service facilites in the USA.(that includes numerous Ford certs, training, and the usual ASE crap certs, plus a degree from community college in auto repair)
We took in 100+ appointments a day, with 60+ techs working there.
Included in that number, and especially since it is a Ford dealership, is an assload of transmission work.

I would have to say, based on what I have seen, that flushing or changing the fluid on a high mileage, never-been-changed-or-it's-been-way-too-long-since trans gives you over a 50% chance that it will fail soon after. It's not a guaranteed thing, as I've seen lots of people do this, then get with the program and start changing the fluid when they're supposed to and never have a problem.
It all depends on how much not changing the fluid has caused your transmision to wear.....you may be lucky, and you may not.

 

[Fingolfin269]

Do you only notice problems when trying to go into reverse and drive? Do you notice any slipping at all when your car tries to go into 2nd gear?

 

[Bassyhead]

Originally posted by: NutBucket

Originally posted by: slag
Its actually a bad idea to get high mileage transmissions flushed.

The fluid contains particulate--wear from the clutch discs. Sometimes when you flush high mileage transmissions, this clears out all the clutch material plus the buildup that the transmisison needed to operate. The "clean" clutch discs now slip and your transmission overheats and boom, new tranny time.

Agreed.

yep