Transmission fluid

[lewisnc100]

Jiffy Lube changed their official name for the service to Fluid Exchange, not a flush. The so called "flush" machines they use like most places just uses the vehicles ATF pump to exchange the fluid. These are cooler line flush machines and have 1 chamber for the old fluid and one for the new, as the old fluid fills up the 1 chamber a diaphragm forces the new fluid back in, the machine does not have a pump or a flush mechanism and just adds back the same amount of new fluid to match what is pumped out.

The problem as ModMech mentions is that not all of the fluid from the pump goes to the cooler line so you are not replacing all the old fluid with new but rather diluting it down with new fluid. This is a faster dilution than you can do by draining the pan but still its the same thing, just all at once. You can accomplish the same task by draining the pan or suctioning fluid out of the ATF fill periodically at much less cost.

For example, my 2000 has a capacity of 12.25 qts. After adding a drain plug to my pan I can easily drain 5qts at a time. Doing 4 quick drain and fills takes 20qts of ATF and gets my fluid to about 88% new fluid mixture, probably close to an ATF flush. Total cost for 20qts of Mercon V is probably around $50 and I think the ATF flushes run much more than that. Plus I continually drain and add new fluid keeping my new fluid mixture pretty constant.

I think any way you keep your ATF fluid in good condition is fine, either via flushes or drain and fills. My only concern is the bad history I've had with Jiffy Lube on even the most basic tasks (tightening a drain plug, reattaching bolts to skid plates, under-fill/over-fill), If you search the internet you'll find quite a few complaints of transmission failures after the Jiffy Lube ATF service. A couple mentioned hooking the machine up in reverse which would build up pressure in the system, can't remember the details on other complaints.

[ModMech]

Actually, all the pump's flow DOES go thru the cooler lines, well 95% or more.

The flow order is: Sump -> Filter -> Pump -> Valve body (~5%, then to sump), Torque Converter (~95%) -> AT Cooler -> Gearset for lubrication -> Sump.

And, if you DEMAND "Mercon V" as you should if your van is a '98 or newer, the cost will go up from the advertised price by $10-$30.

[lewisnc100]

Thanks for the clarification, I think I remember the local Ford dealership quoting around $150 for the flush and Jiffy Lube was around $120, then tack some on for Mercon V.

[Skipjack]

Thanks ModMech.

[Skipjack]

You too Lewis, Thanks.

[atcha]

I am about to do a trans flush on on 98 windstar/3.8L. Chiltons Repair Manual states
- Disconnect the lower transaxle cooler line from the transaxle cooler line fitting at the transaxle
- Attach a 3ft. hose to the end of the transaxle cooler line and gently fasten the hose with a clamp.

What is the I.D size of the cooler line??
How do I identify the cooler line??

Chiltons also states to:
-Insert a plug into the transaxle cooler line fitting at the transaxle to prevent any residual fluid leakage

What size and type of plug do I use??

[wiswind]

I have a '96. I think your's will be the same....except fluid type.
The cooler lines are 5/16 inch I.D.
The total capacity is 12.25 quarts (US).
You will need to make sure that the fluid you use is Mercon V rated.

Now....using my '96 as a point of reference....
The transmission cooler is a part of the radiator....on the passenger side.
The fluid flows from the tranny into the TOP of the cooler....and out the BOTTOM of the cooler. If you follow the line that comes out of the BOTTOM of the radiator.....over to where it switches over to the rubber hose....you will be able to follow it to the transmission. I did NOT disconnect at the tranny.....I loosened the hose clamp on one end of the rubber hose.....and dropped it down.
I found that to be easier.

The method that is mentioned....is something along the lines of.....pumping the pan dry.....add more fluid....pump it dry....and refill....
Just be careful to avoid running the tranny dry for any lenght of time and you will be fine.
Also....measure the amount that you pump out....and replace with the same amount.
Check the level and adjust as needed.

My windstar has a small square-ish block that is mounted in between the metal lines....just in front of the transmission. This is a thermal switch. If the fluid is below about 32 degrees F. the fluid flows through this block...and back into the tranny....bypassing the cooler in the radiator.
For a fluid temp. above 32 degrees F. ... The fluid flows through the lines...through the cooler...and back into the tranny.

The FORD manual does not call out replacing the transmission filter on a regular basis. I prefer to replace it.....and wipe down the magnet (a big washer looking item in the pan) and the pan....so...if I am going to take the pan off.....I am gonna replace the filter. I found (and have read on this forum) that the gasket on the neck of the filter can remain up in the transmission hole.....that can be removed with a pair of needle nose pliers.

The gasket IS re-usable. It is metal with a rubber coating on each side.

I also strongly recommend an auxilary cooler for the transmission.

[atcha]

So you disconnected the rubber hose that comes from the bottom of the radiator and used the hose to drain the tranny fluid.

I was going to attach another hose to this to extend it out close to the driver side door so I can view the flow of fluid from inside to enable me to turn off the ignition immediately when the flow stops.

Is this hose also 5/16-inches I.D?

Also, what did you use to plug the other end that you disconnected the hose from?

The Chilton manual states the capacity to be 10 quarts (9.5 liters)

[wiswind]

I think that the capacity of 12.25 quarts is fairly consistant across the years.
I do not know what the OD of the hose is.
I did not worry about plugging the other end.....
One end of the hose had a "permanent" clamp (you have to cut it off) and the other end had a screw clamp.....I undid the screw clamp.
The fluid does not come out very fast.
I think is is something like a quart in 30 to 45 seconds. If it is slower....you have a problem.
1. problem would be a restricted cooler.
2. would be a weak pump.
You most likely do not have these problems....but I just mention them in case you do.
Actually.....this is the official way to determine correct flow volume.....as per. the alldatadiy directions.
I ran about 15 quarts through.
There will be a certain amount of mixing of old and new fluid in the torque converter. Which is why I ran more through.

When the flow got real slow....and bubbles....I had plenty of time to shut off the ignition.
I used a clear hose (I do not remember the size) that I slid over....so I could see the fluid flowing inside. It was just some clear tubing that I had left over from my garden pond project of a couple of years ago....just happened to do the job.
But...again....the fluid does not come gushing out....more of a nice steady flow....so you have time.

[atcha]

wiswind,
the gasket in the transmission hole is in firm, when I try and grasp it the pliers damage the rubber gasket. The new filter has a rubber gasket on the neck - looks like the one that is stuck in the hole.

Should I remove the gasket in the hole or remove the one on the new filter?
Is there a trick to removing the gasket in the transmission hole?

[atcha]

wiswind,
never mind I got the gasket out

[wiswind]

Sorry that I did not get back on faster....
For others reading this.....this is a common issue.
This is the small FILTER gasket.
You will totally destroy the old gasket when you remove it with needle nose pliers....
I bent a part of the gasket in....from the side of the metal.....and was then able to get a good grip with the pliers to pull it out.

The seal is the small one that is on the neck of the filter....that you press up into a small hole on the transmission.....the one that the fluid is sucked up through.

Not to be confused with the re-usable PAN gasket.