I'm hearing two different methods for getting a flush done.

1) take off the pan, change filter, replace pan and add new fluid. This, I guess, leaves some of the old fluid in. The dealer tells me it leaves too much in. (a friend told me to do it this way to somehow protect the filter from the particulates that get taken up with the flushing)

2) just let the dealer flush it leaving the filter alone. the dealer told me that this in no way is bad for the transmission and that's how they always do it.

I'm not sure what to think as I am in no way a mechanic. I'm leaning toward the dealers method because I wouldn't think dealers would purposefully damage transmissions.

Any help appreciated
Thank You

 

First off what year is your truck? I believe trucks up to 2001 had drain plugs on the converter. The last two times I've done a filter changed I dropped the pan changed the filter and refilled with fresh fluid. I have 199k miles on my truck and no problems with shifting. I talked to a mechanic at the tranny shop i went to have the filter done and he said that they don't recomend flushing. Just drop the pan change the filter and refill with new fluid that is of the correct type. The owner of the tranny shop said to change the filter every 25,000 miles and to check the fluid and smell if it is burnt after hauling a heavy load or pulling.

 

I have a 2000, 5.4 liter. Does not flushing leave a great amount of fluid in? I'm not even sure of the fluid capacity.

 

Flushing the trans is always bad-period. It stirs up debris that's settled in the pan and on the filter,and that debris damages the teflon sealing rings on the output shaft. When the sealing rings are damaged-the trans loses the ability to hold the forward and direct clutches applied.It doesn't take long for the trans to fail afterward. Drain,replace filter and refill.
JL

 

i agree with the drain and filter. transmissino holds 5 quarts, entire system is 13. putting in 5 quarts every 2 years should be fine, keeps the addatives fresh. like mentioned, if truck is 2001 or before, it has a plug, and you can drain the converter also and get the entire change.

 

Another technique is to first drop the pan, clean it up replace the filter. Then remove the return fluid line to the trans from the cooler. Place over a 5 gal bucket or pan. Fill pan thru the dipstick. Have someone turn on the truck and idle. The engine will start pumping out the old trans fluid. Keep the pan filled as the fluid is pumped out. Just watch the fluid, it will change to a lighter color when the new fluid cycles through. Turn off the truck and button everything up. It worked great and didn't involve a high pressure flush. I had replaced roughly 5 gals when I was done. This was also on a 95 F-250. But it's the same principle. Tranny still running strong.

 

At almost $4/qt for Mercon V,that'll get stupid expensive really quick.
You can do the same thing before you drop the pan. Pull the hose loose,and fire it up.As soon as the fluid starts ti sputter the slightest bit-shut it off,and then drop the pan removing the remaining fluid from the system. Change the filter,and then refill it-that'll get the majority of the fluid out,and is the only good way to do the '01-up models with no drain plug in the converter.On the older models with the drain plug-just drain the converter and drop the pan.
JL

 

so on a 97 f250 5.4l i should have a drain plug on the converter. once i drop the pan and pull the filter will the plug be pretty obvious from there or what, i wrenched a motor a few times but i never touched a tranny other than fluid checks from up top. i know what the torque converter looks like though just like i said never been inside an actual tranny

 

Yes,it should have a drain plug,and it also should be a 4R100. The drain plug on the converter will be on the converter itself-you'll need an 18mm socket and ratchet to turn the crank and line up the drain plug with the access hole in the bellhousing. I always drain the converter first-it gets the largest part of the fluid out,then I drop the pan.
JL

 

I understand it's expensive. But I wanted to replace the entire amount of fluid or as much as I can. The tranny holds approx 20 qts. About 5 gals. So 4$/qt x 20 qts = 80$ plus the filter kit =20$ to 30$ That puts the total around 100$ to 110$. I also have the assurance that the job was done right and to my specs. Now how much does a flush cost? I was quoted between 170-220$ and as alot of people are concerned about, did the flush do any damaged? Did that 20 year old kid know what he's doing? I heard stories about a quick lube place not threading a oil drain plug on properly after a oil change and the owner drove off trailing oil behind him until the engine seizes up. It's just the way I am, I don't trust anyone working on my truck. I rather spend the money and do it myself. Johnny, does your technique remove all the fluid? I would think as soon as the fluid is gone out of the pan and the pickup is sucking air, the fluid in the converter and cooler/lines won't move any more and is stuck. And if it does clear all the fluid out wouldn't it take the same amount of fluid as my way to refill it? So the cost would be the same. Also another reason why I do it my way is to keep air from getting into the system. I don't want to risk any damage from running it dry. You are a wealth of knowledge on these forums Johnny and you are helping me greatly on my engine swap I appreciate all your help.

 

If you're talking about you Expy-it should have a 4R70W,and that 4R70W holds 12-13 qts max.
The best way to service it is to drain the converter via the plug,and drop the pan. The other method that I'm speaking of removes about 90% of the fluid,and the minute amount that's left will not harm anything as long as you don't have a failure of the trans and the debris associated with that.
One thing that you're worrying about-you're never gonna run the pump totally "dry" and damage it unless you sit there with it running for a 5-10 minutes with no fluid. The total system capacity of the trans includes the lines and cooler,and the way you're talking about "flushing" it will use alot more fluid than is necessary,and you'll be contaminating the new fluid with the old fluid as quick as you can pour it into the system. You can also get a filter for around $10 at most places-if you look around.
JL

 

I'm baseing my method on a 95 F-250 so my fluid #'s may be high. If your way removes about 90% and have a very slight risk of damaging the tranny by allowing air in the system, then I can live with that. I don't have the converter drain plug unfortunely. But I see the advantages in your method and it make sense. See I just learned a new way of flushing the tranny. Thanks

 

As long as you shut it off when it starts spitting air out of the line-you're not gonna damage anything.
JL