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Changing Tranny fluid??

3K views 12 replies 9 participants last post by  ScottyP5947 
#1 ·
Im about to change the tranny fluid with Amsoil synthetic ATF. Is dropping the pan good enough to drain the fluid, or do I have to pull the tranny?
 
#2 ·
the pan is usually what I do but remember there will still be several quarts in the torque converter. Another option is to get it flushed out which they use a similar process as with a coolant flush.
 
#3 ·
Yeah I think the pan holds around 6 quarts and you will get another 6-8 out of the torque converter, so if you going to change to synthetic you should do a total flush probobly 18-20 quarts to do that.
 
#6 ·
yall are over thinkin this :) dont pull your tranny to get to the converter.
the way ive always done it is drop the pan and clean it up and put a new filter in and replace the pan, then fill it up to the proper level, then disconect the return line fron the trany cooler and put a chunk of rubber hose on it and run the hose into your drain pan. next start the truck and once the fluid coming out of the hose starts to come out clean shut the truck off and fill your tanny back up. this not only emptys out the torqu converter but it also flushes all of the old fluid out of the tranny cooler and lines as well.
this procedure works best with two people. one watching the fluid coming out of the hose and the other pouring fluid into the fill tube while it is running so you dont run your transmision dry while its pumping the rest of the fluid out plus it easier for the guy up top to turn the truck off when the guy underneith yells at him that the fluid is coming out clean :)
 
#7 · (Edited)
Not sure where any of us told him to pull the tranny to change his fluid? But yes that would be counterproductive in my opinion. You have a few options before I would pull the tranny!;) You can take it to a garage that will flush your transmission and put in new fluid of your choice. Here in my neck of the woods its 75 bucks to have it done, or you can do the diy method outlined here:

Changing ATF in a '99-up SuperDuty

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 ATF. You may use either conventional or synthetic, as long as it meets the above requirements.
b. A 10 foot length of clear tubing and one hose clamp, sized to fit over your cooler hose. There have been different size cooler lines over the years, so check before buying!
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.
2. Drain the pan, then replace and tighten the drain plug.
3. Pour 7 quarts of new ATF into the filler [dipstick] tube.
4. Disconnect the transmission-fluid return line at the transmission - from where the ATF returns to the transmission from the cooler. This is the line towards the rear of the transmission. Clamp the clear tubing over the line that you removed from the transmission. This is where the old ATF from the torque convertor and coolers will come out.
5. 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 until you see some air in the clear tubing. As soon as you see air shut off the engine.
b. While the engine is running in step 5a 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. Refill through the dipstick tube with 6 quarts of new ATF. (That's 13 quarts total so far).
6. Repeat steps 5a and 5c. (That's 19 quarts total so far).
7. Remove the clear line and reconnect the cooler line to the transmission.
8. Check the fluid level and use the last quart of ATF to top off.
9. Properly dispose of the used transmission fluid.

P.S. This isn't my writeup and Im not sure who's it is to quote them!
 
#12 ·
I know this is an old thread. Is it still the recommended method to drain and change auto trans, in our trucks?
 
#8 ·
Excellent idea using the return line, good to know somebody was thinking! Thanks guys, $130 bucks in tranny fluid..........:(

BTW I can get Amsoil at dealer cost if anyone in the minnesota twin cities area is interested feel free to PM me!
 
#9 ·
LOL his write up was a little more technical then mine sorry :)
 
#11 ·
I have tried 2x mixing Amsoil ATF with used ATF and I had to eat the Amsoil I threw away, so the answer to your question based on my opinion is NO.
the transmissions on both vehicles just didn't act right till I filled it 100% Amsoil. I had to throw away a case of Amsoil ATF:rain:
on the bottom of the bellhousing there is a rubber plug, remove this plug.
with the plug removed you need to spin the engine over till you see the convertor drain plug, it is a 7/16 sized plug, remove it and every bit of ATF will come out. reinstall plug and rubber plug and you are done.
now if you have a aftermaket convertor then you may not have a drain.
if that is what you have, you have to flush it out, just pull one cooler line and put into a large container.
then with your pan reinstalled and filled with fresh fluid about 5/6 quarts, crank up the truck and pour the remaing fresh ATF you will need, watch the bucket filling with old ATF, as it fills it will turn from dirty fluid to fresh and red, at that point turn off the truck and rehook the lines and check the level and then your done.
 
#13 ·
Yes sir. This is a good way of going about it. I just did it recently and just kept track of what came out, and put in the same exact amount and ended up with the level being perfect.

Good luck!
Scott
 
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