The recommendation on a certain Japanese truck I have is to drain the trans pan through the drain plug every 30K miles. The trans holds 8 quarts and you typically get 3.5 quarts out of the pan (if you let it drain overnight). They don't recommend removing the pan or replacing the filter.

The fluid has always looked new on the dipstick, but then again the tranny temp never exceeds 180F on the gauge, even in Omaha at 106 degrees F ambient temps. At 151K miles, the trans shifts like new.

So, given the mess/pain of pulling the pan each time, I'm a reasonably big fan of the 'multiple dilution method' mentioned above - especially when recommended by the manufacturer!

Steve

 

Does anyone flush out the transmisson system?

 

The drain plug is one more place for fluid to leak out

4R100's came with the drain plug built in.

 

Great info,, just finished. Mercon Mercon III Mercon V.. ? now lets throw in dextron,, what to use. I went to the Owners manual and found info on specs and Mercon III is ok to use. My Ex. 7.3 was bought used and now has 125K on it and I don't know if the fluid was ever changed. So what the heck!.. Time for change. Ford says the pan gasket is reusable. My luck,, not a change so I bought the FORD Filter and Gasket at my Friendly Ford dealer. I bought 17 qts of Mercon III / Dextron. Time to change. Rain every day. Last 3 days 2.5" /day minimum so have to change before it rains. I pull the dust cover over the torque converter looking for the drain plug that was deleted starting in 01. Mine is 00. Turned motor easy once with starter and danged if the plug wasn't there. Now on the face into the flex place but on the radius outside of the converter. So take a change it would only cause me to pull tranny to fix it. I used a 6 pt socket and carefully removed the plug with the dipstick out. The oil drained about 10 minutes what appeared to be about 8 qts. Didn't measure. Then I carefully put the plug back in and tightened with my arthritic wrist until the joints clicked. Next pull the pan. Everything was telling me,, naw,, don't just drain the oil,, but what the heck. I had a new filter and gasket ready to use. The 3 bolts on the rear of the pan were difficult to remove. What size. 10 MM. Drain the oil on the pan what size. 9/16 if I remember correctly. I ONLY USE 6 POINT sockets on this type of work. Never round off any fastener. After megga amounts of oil was drained I installed the drain plug and pulled the pan. Wow 125K and the tranny was clean as a whistle inside. The filter came out easily with a little wiggle. The new filter oring was lubed with tranny fluid and it went in easily. I cleaned the pan and looked at the gasket which looked new. Danged the hang why not try it.. UMHHH I used sewing thread in about 5 places to tie the gasket in place. The gasket is 2 side rubber metal inside. The gasket stayed in place and the pan easily fit back into position. Doing the circus act I held the pan with 1 hand searched around for the pan bolts and got 1 in,, luck would have it I found the 2nd bolt where the first was. After the second was installed I put the rest of the bolts in and hand tightened. Then using something that appeared to be a cross hatch pattern tightened all the bolts. Ok,, Now I know I didn't get all 17 or so qts out but really didn't know how much came out. Took 15 1/2 qts to refill. After the first 5 qts I started the 7.3 up. Then added oil while running. At 12 qts I backed it off the ramps. Then shifted through all gears and added oil in 1/2 qt increments until I was in the safe range. Crossed fingers looked under and you would not believe what I saw. Totally Dry no leaks and the dreaded torque converter was not leaking either. SO test drive for 40 miles at hw speeds up to 80 mph. Back home,, still dry. So danged might be my lucky day,, clean tranny,, new fluid and no leaks. Now for the old oil. Looked like motor oil it was so black. Only red tint nothing like fresh oil. But it also didn't have a burnt smell either. So maybe I missed the bullet. The other thing I found was the vac. line to the auto hub was off but I didn't take time to pull the wheel in the 95 Degree temps 100% humidity and waiting for the rain. But alas,, tomorrow morning the wheel comes off. Now If I just knew where the danged vacuum line attached to the hub.

Moral of the story,, go ahead and change the oil. If you don't have the drain plug there is a technique of removing the rear tranny line and pump the oil out. Best of luck Jim

 

OOPS. it was only 70 mph.. :-) typo of course.