Ford is constantly telling me to have my transmission flushed with their cold flush machine. Im at 87k miles and tow 10k lbs a few days a week. After research it seems i need a hot flush machine. No one in louisiana has ever even heard of a hot flush machine. So i ask my neighbor who is a transmission guru (owns transmission depot and a race team for 30 years). He is telling me that flushing the transmission is the dumbest $200 you can ever spend and ford service techs dont know anything about transmissions, except what they are told, which is to flush them. Mixing 8 quarts of fresh oil with the old oil is a joke, the torque converter holds majority of the oil on this transmission and the flush machine would take days and days of running to flush the oil out through the 1/8" line in between. He says the only thing he would ever do with this transmission is drop the pan and let it drain the oil thats there (about 8 quarts) and install a new filter. And reinstall the pan. He claims that by doing this every 20-30k miles, is way way better for the transmission. Flushing is a complete waste of time. Makes sense to me. He charges $120 to drop pan change filter and 8 new quarts of oil, or $190 to flush it. He says on his personal vehicles he would never flush them.

Thoughts? .

 

I have been doing this every 50K. I also do this with both cooling systems. No need to worry about checking the coolant, just change out what you can drain.

 

flushing gets the deposits out. And you have to use a heated one because of the thermostat in the tranny that allows the fluid to circulate when warm.

He is right that most shops don't have anyone that works on trannys.

 

My wife had a '99 Mitsubishi Montero, according to the service manual, the transmission would not need service until 60K (if I remember correctly) and their (Mitsubishi' s) recommended procedure was to "flush", the transmission on the initial service. Well, I figured I knew better, had my local shop change the fluid and filter at 50K, no problem right, wrong.... it seems that once the New fluid circulated through the system, I pulled all kinds of varnish from the lines and I was right back at the shop dropping the pan and changing the filter again. I basically performed the "flush" unwittingly in about a 30 mile round trip. Thankfully the shop owner didn't gig me Too hard on the second service, lesson learned though. I know they're two complete different animals, but the basics are the same. Oddly enough, the next transmission service interval didn't require a flush and was a shorter mile interval, I assume that since the initial service interval was high miles(for 1999) they anticipated issues with varnish in the lines. I know fluid technology has changed a lot since then as have transmissions, but I have learned to pay attention to manufacturers recommended service intervals / procedures, and not stray too far from them.....

 

Do not flush, or drop the pan. Just take out the drain plug, drain, replace and fill. Drop the pan and change the filter as recommended in the book. I think that replacing the fluid every 30k miles and the filter as recommended is a good way to go.

 

I'm a bit surprised or maybe not that someone would offer a transmission flush to his customers, but wouldn't do it to his own vehicle.

My previous 05 Super Duty had the tranny flushed every 30k miles and I never had a transmission problem, but maybe it wasn't needed.

 

On some things, I would rather be safe then sorry.

I don't like to stray too far with what is recommended. I might question them on it and if I still find the answer iffy, I might not do it. But something like this, I would do it. Now at my dealership, I had to request the hot flush.

Now, I could see where some dealerships would try to push some service that aren't needed, so I am not saying you might need to question why they are recommending something, but as someone that also does quite a bit of towing, this to me wouldn't be one of those times. Now, may it not be doing any good.... That is possible. But if performed correctly, I can't see it doing any harm. While not doing it may cause problems. Towing would bring that out quicker.

Just my two cents on it.

 

Back in the olden days, there were some cars that not only had drain plugs in the transmission pan, but drain plugs in the torque convertor as well.. We used to get all but maybe a pint of the old fluids out of them. I never heard a good reason on why they stopped doing that... They may have saved $2 worth of plugs and parts.

For what it's worth, if the manufacturers would offer a "Serviceability" option for $100 that includes things like drain plugs in the pans, convertors, rear ends as well as greasable Ball Joints, Tie Rods and U-Joints --- I would be all over spending that money!!!

I have a couple of friends that own shops. One has a trans fluid flushing station. He claims to get 80% fluid exchange at the cost of two extra quarts. They are done hot also. I asked him if that's how he services his stuff and he said heck no.. The flush does nothing for the filter. But what he did say is that it stopped vehicle come-backs because of pan gasket leaks. Probably because they never touch the pan to begin with...
So, if it were me, I would do a manual fluid and filter change and 30k later have it hot flushed, 30k further down the road, do the filter again and so on..

 

Yep, my first super duty (7.3L) was like that, got all the old out and the filter. Then all the new in including filter. And I think the gasket was reusable. Man, those were great trucks. Saw one the other day with 51,000 miles I think t said. Wanted 25,000 dollars/ probably get it too.

 

On my 6.0h that I put 340,000 miles on. I tried to drain the pan every 15,000 or so. The tranny made it 275,000 before I rebuilt it. They were hard miles while tuned and a lot of towing so I was pleased with it. The fluid always came out bright red. On my 6.7s I usually drain the pan every 30,000. I've been trading them every 2 years so I'm not as **** anymore it doesn't come out as clean as the 15,000 interval but still not bad.

 

Ford says 150,000 miles for our transmission. Even being cautious and changing at half that it's 75,000.

 

Although I haven't done it on this 6.7, why not let the trans pump the fluid out itself? aka pull off the return line and put it in a bucket. I've done C4s, 4R100s this way and it works great. The new fluid is pushed through the torque converter. No pan seal to mess with. You can physically see the fluid change color when you have pumped the new stuff through.
1) remove fluid return from trans and route to 5 gal bucket
2) start engine, shut off when bubbles appear
3) add as much new fluid as came out
4) repeat 2 and 3 until fluid capacity + a quart or 2 is reached. Put in drive and reverse as you go to get fluid though valve body/clutch circuits.
5) re-attach return, top off fluid

 

How else do you drain the TC, short of actually removing the TC, when you just drop the pan to do the flush and filter?

 

If the fluid isn't hot then it won't work.

 

I think he means to just do a partial flush, but the best and easiest possible way. I was thinking the same thing, let it pump out from the bottom of the radiator to nearly dry, maybe adding a few quarts thru the dipstick tube.

Then top off and drive... What I like about this is the ease, and that it may be a good home treatment for shudder / old fluid. Also as a pre-treatment before doing a BG flush.

That's my plan, a homeflush for 1000 miles to clean out the valvebodies and dump any much into the old filter. Then a hotflush will surely be a complete service, with a new filter. Gotta be good for 50k-60k.

I'm at 108k with a truck I just bought, unlikely service history.