I've done this alone. It's easier with a second person, and sometimes helps prevent spills.
1. Things you need to get started:
a. The transmission system holds almost 18 quarts of ATF, and you must waste a couple of quarts to be sure you get it all purged and replaced, so buy 20 quarts of MERCON V ATF. You may use either conventional or synthetic ATF, as long as it is rated MERCON or MERCON V. Your Owner’s Guide says to not use MERCON V, but Ford changed that in 2006.
b. A 10 foot length of clear tubing and one hose clamp, sized to fit over your cooler line. There have been different size cooler lines over the years, so check before buying! The metal part of your cooler return line is probably 3/8th inch outside diameter (OD) with a ferule on the end of it, so if you can find 7/16th inch inside diameter (ID) tubing, that will probably work great. If you use ½” ID, it will be a loose fit over the ferule and will need a good hose clamp tightened good to prevent it from leaking. So just in case, place a big drain pan under the connection. And some folks have reported they were strong enough to force a 3/8th inch ID tube over the ferule. If you try that, dipping the end of the plastic tubing in very hot water for a few seconds will make the job easier.
c. If you don't already have a special funnel that fits into the transmission dipstick tube, then you will need one of those, too.
d. If your transmission has ever been worked on by a Ford dealer, you probably have a Magnefine in-line filter in the "rubber" part of the cooler return line, near the front axle. If so, you should replace that filter every time you change the ATF. You can get one from your Ford dealer, or for about $15 from Magnefine Filters--Online Order Form. Your cooler lines are probably 3/8th inch, so you want the 3/8th size Magnefine inline filter.
2. Note: In cool or cold weather, be sure the transmission is up to operating temp before you begin. It’s not supposed to happen, but several members have reported ATF coming out the cooler bypass line instead of the cooler return line if they tried these procedures with a cold transmission. Also, in cool or cold weather, keep the new ATF in the house so it’s around room temperature of about 70º F. when you pour it in the transmission.
3. If your pan has a drain plug, drain the pan, then replace and tighten the drain plug. If it doesn't have a drain plug, skip to step #5.
4. Pour 7 quarts of new ATF into the filler [dipstick] tube.
5. Disconnect the transmission-fluid return line at the transmission - from where the ATF returns to the transmission from the cooler(s). This is the line towards the rear of the transmission. This is where the old ATF from the transmission, torque converter and coolers will be pumped out. Clamp the clear tubing over the line that you removed from the transmission.
The following is a drawing of the 4R100 transmission, seen from the passenger’s side of the vehicle. The arrow at #2 shows the banjo connection where the cooler return line and the cooler bypass line connect to the rear of the transmission. The arrow at #4 shows where the “hot” line and the cooler bypass line comes out of the banjo connection on the front of the transmission. (The cooler bypass valve is near the banjo connection at the front of the transmission, in that bypass line that runs between arrows #4 and #2.)
6. This is where the second person comes in handy. One person starts the engine, while the other holds the line over the drain bucket. A clothes pin can replace the person holding the line in the bucket.
a. Run the engine at idle RPM until you have around 1.5 gallons in the drain bucket, then you should see a big air bubble in the clear tubing. Ignore tiny bubbles. As soon as you see a big air bubble, shut off the engine. Then double-check the amount of used ATF in the drain bucket. You should have around 1.5 gallons. If you have much less than 1.5 gallons, then you probably killed the engine too soon, so crank the engine and pump out some more old ATF.
b. If you drained the pan in step 3 and poured in 7 quarts of new ATF in step 4, then while the engine is idling in step 6a above, move the shifter through each position from P to 1, pausing about 5 seconds at each position. This will change some fluid that would otherwise be trapped in the valve body, accumulators, and clutches.
c. If you poured in 7 quarts of new ATF in an earlier step, then refill through the dipstick tube with 6 quarts of new ATF. (That's 13 quarts total so far). If you have not poured in any new ATF yet, then pour in 7 quarts of new ATF, for a total of 7 quarts so far.
7. Repeat steps 6a and 6c until you have poured in a total of 19 quarts of new ATF (7 + 6 + 6).
8. Remove the clear line and reconnect the cooler line to the transmission with 20 lb/ft torque.
9. Drive the truck several miles to get the transmission up to operating temperature. Then check the fluid level and use the last quart of ATF to top off.
Note: You should always check the ATF level when the transmission is up to operating temp – not when it’s cold. The cold marks on the dipstick are not very reliable. When first filling the transmission, use the cold zone on the dipstick to get close to the right amount of ATF in the transmission. But for topping off, do it with a hot transmission using the hot area of the dipstick. When you get done, you want the transmission full, but not overfull.
10. Properly dispose of the used transmission fluid.
11. Congratulate yourself! And your engine starter/killer person.
12. Then get back on TheDieselStop and tell us your "lessons learned" for those that follow you down the DIY road.
Now that we understand the basic procedure, let's muddy the water with the options:
Optional: Change the internal transmission filter. Revise paragraph 3 above to read:
3. Drain the pan, remove the pan, replace the transmission filter, clean the inside of the pan and clean the reuseable gasket, install the pan, then replace and tighten the drain plug. Torque pan bolts to 11 lb/ft.
If your pan doesn't have a drain plug, you remove and drain the pan at the same time. This might be a messy job, but most tranny pans on other vehicles don't have a drain plug, so you won't be doing something the pros don't do routinely.
Don't buy a new pan gasket. The original is reusable.
The pans for the 4x2 and 4x4 drivetrains are slightly different, so the internal transmission filter is also slightly different. So be sure you buy the correct transmission filter for your drivetrain.
I replace the transmission filter every other fluid change. Note that Ford does not recommend ever changing the filter. I've opened filters with over 300,000 miles that were not even close to being clogged.
It just pulls out, there are no bolts that hold it. It is held in place by the pan. Make sure that the O-ring is removed, too. Sometimes it does not come out with the filter.
Optional: Drain the torque converter. Add the following to paragraph 3 above:
If your truck was built before August, 2001, then you may have a drain plug in the torque converter. If you do, then you can also drain the torque converter as part of step 3 above. Some people think it is necessary, but I don't. Running the engine in the next steps will pump the fluid out of the torque converter. If your transmission was built after August 2001, you don't have a drain plug in the torque converter.
If your torque converter does include a drain plug, then to drain the torque converter remove the shield (but NOT the upper right bolt - this one only needs to be loosened) and turn the flywheel until you see the drain plug. If you drain the torque converter, be sure to replace the drain plug, and torque it to 18 to 20 lb/ft before you continue.
If you drain the torque converter, then the old ATF won't come out of the end of the cooler return line until the torque converter is filled with ATF. So instead of waiting until you see big air bubbles in the drain line during your first iteration of going through in step 6a, run the engine for about 30 seconds while changing gears for step 6b, then cut off the engine.
Optional: Blow out the coolers. Add the following to paragraph 5 above.
It's not necessary, but some folks want to get every possible drop of the old ATF out of the system before they pump new ATF through the system. If you drained the torque converter, then you might also want to blow the ATF out of the coolers and cooler lines. If you have an air compressor, you can reduce the line pressure to about 15 PSI, remove the cooler "hot" line from the front of the transmission, and blow air into that line. That will force the ATF in the coolers and lines out the cooler return line at the back of the transmission. DO NOT use air pressure of more than about 15 PSI! Then be sure to reconnect that line before you continue with paragraph 6.
Last edited by Mark Kovalsky; 10-26-2013 at 09:36 AM.
Reason: Added note clarifying that this does NOT work with a TorqShift transmission.
Additional pointer for anyone doing this for the first time:
A bit of fluid might come out of the bypass banjo a few seconds after the truck is started and/or when switching through the gears. Dont just assume the bypass is active. Let it run for a few seconds and see if it stops. I turned off the truck before I realised it would stop and wasted the 7 quarts driving around getting it "Back" up to temp.
Be ready for about a pint of fluid to come at your head when you pull the filter loose.
2002, F350, Lariat, CC, LB, PSD, QLJ5, A/T, ESOF(with hub disable switch), LS, Off Road pkg, AIC, Jordan 2020, X-monitor, IAH removed, Fuel pressure shimmed, DP-Tuner 80 econo, acetoned badges, 315 BFG's on Alcoa's, 4"DPPI exhaust, Sonnax/Tricumulator, DIY BIG air filter with ZooDad, Bilsteins, EBV removed, WW, Proflex SS sleeves over the orange manifold hoses, MAP connected to adjustable pressure regulator, EBPS connected to intake manifold, Red line disconnected, Modified factory wastegate, 200 amp large case alternator, AutoEnginuity, Chris Thompson, SoCal Biodiesel Users Group member, Soon to have a bunch of goodies from Riffraff Diesel.
My buddy thought the same amount would be recycled through by just continuous changing of the "pan" fluid.
I thought you needed to drain through the cooler line as more of a "bleed" so all the air was removed.
__________________ 2001 SuperDuty Lariat Crew Cab 7.3L Mods: 6" lift Skyjacker, ProComp 33's on 16's, Edge J/A stacked with Evo., AFE Stage 2, 4" Turbo back, Rebuilt 4R100 with FTVB and PML pan, Polished PML diff covers, Tank mod. Future mods: Powerslots with Hawks, Wicked Wheel, ATS Housing.
Hey Mark and Smokey, what is the advantage to switching to Mercon V instead of Mercon III? My truck has 185,000+ on the original tranny and really don't want to cause any problems as it shifts the same as it did when new. I change the fluid, internal filter, and the spin-on filter in the cooler return line every 30,000 miles and the pan is always very clean. I have a converter drain plug and have been using Napa filters and Valvoline fluid at every service. As always, thanks in advance!
Y2K+1 F250 SC LB 4X4 Lariat Bob Riley 203 thermostat and housing, FL1A trans inline filter, Superchip tuner @ 60HP, CCV, Heater valve mod, Bob Riley H/X hose. pre-pump and harpoon. napa 3121 primary fuel filter. access rollup bed cover. spare cps in glovebox. diesel innovations regulated return kit. summit 4" exhaust. previous trucks:
1973 f-350 4x2 360 4 speed.
1979 f-150 300 3 on the tree.
1987 ranger s/c 4x2 2.9 auto 203,000 trouble free miles.
1988 f150 lariat 4x4 300 4 speed
1997 exploder exploded and retired...
2004 freestar van
ASE master heavy truck since '93
The first advantage is the MERCON V exists, there never has been a fluid called MERCON III. There has been MERCON, MERCON V, MERCON SP, and now MERCON LV. Never was there a MERCON III.
The 4R100 was designed using MERCON. In 2006 Ford stopped licensing MERCON and changed MERCON V to be compatible with the 4R100. There is no great benefit or problem switching from MERCON to MERCON V in a 4R100.
__________________ Mark Former Automatic Transmission Engineer 1988-2007
“The good thing about science is that it's true whether or not you believe in it.” ― Neil deGrasse Tyson
changed the fluid and filter on my 03 f350 used the mercon v fluid. Cant keep trany cool iv flushed radiator cooler and external cooler and blew them both out.. dosent matter if im loaded or empty fluid will be steaming in 20 minutes.. Any ideas???
I changed mine last night and it went pretty well. I ended up putting the hose on the exit from the trans cooler up under the radiator on the same side and the transmission fluid lines. I put in a small link of 3/8" OD copper pipe to stick in the rubber hose coming from the cooler. The other end was hooked to some 3/8" ID Tygon Tubing. There was a lot of junk in the way on my Excursion next to the transmission on the side where the lines were located so I gave up hooking the hose there.
I also removed the pan and did not find anything at all there accept a little steel stuck to the magnet. There was no aluminum or clutch debris. This helped give me confidence that changing the fluid might fix the torque converter buzz on lockup problem.
I think I screwed up and purged the fluid after adding the last 6 quarts when I should have stopped there. I drained the pan then added 7 quarts. I pumped that out and added 6 more quarts and purged that. I added the last 6 and purged that out but I should have stopped there and checked the fluid level. I ended up with about 7 gallons of waste since I purged too many times. I had to add another 6 quarts after the last purge to get it back on the dip stick. My dip stick is really hard to read especially after having just added fluid. The residue in the tube coats the dip stick making you think it is full when it is not. If you look at both side of the dip stick you can get some idea of what it is doing. Usually only one side is fully coated with oil.
This thing only had 94k on it and the fluid was shot. This was a soccer mom vehicle that saw alot of daily driving but not much in the way of pulling. I am pretty sure it was the original factory fill of fluid that came out. Now imagine a powerstroke pulling heavy loads and putting out tons of torque. Just imagine how much quicker the fluid is going to degrade when the truck is actually being used for what it was designed for.
I have tried the procedure twice now, both times with the tranny fluid "hot", and it continues to purge from the bypass. I have stopped both times after a gallon came out of the bypass and only retrieved approx. a quart from the cooler return line. Does this denote a problem with the bypass?
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