ATS service, "flush" vs pan-drop and filter?

[bp fick]

Older Honda's had a drain plug on the trans. (don't know about newer ones). The severe duty schedule called for draining and refilling every 10K miles. It is only about half the fluid. But, since it was easy to do, I always did it.

3 quarts out, 3 quarts back in, every 10K. Sort of rotating and refreshing.

12 years later and 200,000 miles, no issues. I dunno.

 

[MyJoBota]

Just look at who pushes the flushing service. It's the quick lube places looking to make a quick dollar with out doing much work. They also usually use a generic fluid that more times than not doesnt even meet your vehicles requirements. There may a time and a place for flushing (catrophic failure inside) but I for one will surely drop the pan and changed the filter on vehciles so equipped. You will learn alot about what is going on inside that transmission just by seeing what is in the pan and filter.

 

[JimRB]

I am confused about all these people who talk about flush versus drop and drain. In days of old when I lived at home (30+ years ago) my brother rebuilt transmissions. That torque converter holds a lot of fluid. Well I am assuming it holds a lot of fluid as it looked like a big donut. So folks who drop a pan, change filter, adjust bands and add 6 or 8 quarts of fluid still have the tranny cooler and the torque converter of old fluid. I suppose one more fluid change after running a few miles would dilute the old fluid down.

So here are few questions. Can you blow out the tranny cooler line to empty that fluid from the tranny cooler lines? Does blowing out that line matter as that fluid gets pumped in soon and the air is purged out? When the factory installs a transmission do they do some sort of pressure fill that purges the air out of the cooler lines and the torque converter? I know that when you rebuild a Chevy engine you get your drill out and your oil pump adapter to prime the oil system. I did the same last water cooler VW engine I had apart.

I need to do service on my new to me Dodge. I think I will do the bands adjustment, filter change and fresh fluid followed up with another fluid change later when it gets warm again. I also need to look at brake fluid change (Motive Power Bleeder which I already have for my VWs. VW says change fluid every 2 years StoreFront -- Motive Products Online Store ) and rear axle fluid change. Maybe power steering fluid change as that looked kind of disgusting. Power steering change might be easier because in theory I could remove belt and return line, attach air ratchet to pump and spin around to flush out old fluid. Cummins is new to me.

 

[JCByrd24]

The proper flush is done by using the vehicles own transmission pump as the pressure source and a simple device that connects to the transmission lines (usually at the radiator or aux cooler) that collects the old fluid while also putting in new fluid. Usually this is a just a large cylinder that has a sliding, sealed disc that separates new from old fluid. The old fluid is pumped out, pushes the disc, which in turn forces the exact same volume of new fluid in the return line. This changes the TC fluid, doesn't use excessive pressure or back flow, and is in my opinion relatively harmless. This can be replicated in your garage, but is much trickier and requires a helper. Any "power flush", "high pressure flush" or "back flush" should be avoided. Obviously the right fluid is key.

For the OP, I think you are in pretty good shape, mostly likely significantly better than most people. Where you have a relatively new filter, I think you probably could get away without a filter for quite some time. A trans filter is not like an engine oil filter, there should be relatively few contaminates to worry about, especially after a break in period, as demonstrated by the lack of filters on newer vehicles.

Another option that hasn't been discussed, is to add a spin on type filter inline to the cooler, so that you can change a filter regularly without the mess of dropping the pan. These filters will usually be significantly finer than the pan filter, and would negate the need to ever drop the pan (after an initial change from the original perhaps). I did this on my old explorer, it was quite popular due to known weak trans.

 

[Toyboy]

The best way I've seen a complete change out of fluid is to remove the line going to the radiator . Have a big bucket ready and start the engine . As the fluid is being pumped out keep adding at a similar rate w/fresh fluid (two person job). When the fluid starts running bright colored like the new, turn the engine off and reconnect the line . Start again and check level and add as needed.

Dropping the pan doesn't always give you the true story of whats going on inside. Had my '05 done, clean as a whistle. 3000 mi later #3&4 clutches went while I was just cruising at 55. Go figure?

 

[oldballs]

Does the vehicle transmission flushing discussion apply to the hydraulic/transmission of small tractors? I forgot about the dropped pans/filters that I used to do on my old vehicles when first replying to OP. I guess those are two different subjects.

 

[clemsonfor]

No tourqe converters are filled before installed, they cannnot be emptied on vehicle it will ruin them. Have to flush it all out, but if you do a pan change before its cooked it is how its suppose to be done. The fluid is not toast yet so the new oild puts additives back in and dilutes old with new you keep doing this in theory before you cook it all up to need complete replacement and its to late.

Side note my 01 TOY highlander has no filter just a drain plug on pan. Also the dipstick says no need to change trans fluid. But in book under severe duty i think it says to dump pan and refill every , not sure how many miles?

I did the first time at about 115K (we bought it at 80k so not sure about previous life) but pretty sure it was the first time as i have a service book pretty well filled out and it dont list it. $35 for trans fluid every year to me is cheap ins. and i also tow a bit in the summer with it!

 

[MyJoBota]

The best way I've seen a complete change out of fluid is to remove the line going to the radiator . Have a big bucket ready and start the engine . As the fluid is being pumped out keep adding at a similar rate w/fresh fluid (two person job). When the fluid starts running bright colored like the new, turn the engine off and reconnect the line . Start again and check level and add as needed.

Dropping the pan doesn't always give you the true story of whats going on inside. Had my '05 done, clean as a whistle. 3000 mi later #3&4 clutches went while I was just cruising at 55. Go figure?

I can assure you there is more to this story. Clutches almost never just fail without a Red Flag. Keep in mind if a clutch pack is slipping it is creating heat and degrading the fluid witch will show in color and smell. I would sooner think you experienced a hard part failure.

 

[newbury]

I've been doing it all wrong, I just replace the fluid.

For about 15 years my tranny on my '88 E350 has been leaking fluid. I put a drip pan under it usually. About 100,000 miles ago I asked my diesel mechanic about the cost of repairing/replacing the tranny and he quoted me about $3K, and said that those era Ford C6's always leaked fluid.

I've probably put about a max of 2 qts of tranny fluid in each year over 15 years. So I've probably changed the fluids several times over.

 

[automech]

I dropped the pans and replaced filters for years. Never saw a clogged filter on a trans that had no problems. The only time I saw a clogged dirty filter was when the trans had taken a dump. Usually you get not even half the fluid out of a trans doing this. It's better than nothing. I use a flush machine now. Plumbed into the cooler lines, uses the vehicles pump. Out with the old, in with the new. Use whatever fluid the manufacturer calls for or a high grade universal synthetic. The perfect service would do a filter and a flush, but if I had to recomend one it would be the flush.