4L80E Oil change

[glivingstone]

Hi Guys,
Looking at changing the oil in the tranny (4L80E).
Can anyone tell me how I can get the oil out of the converter, radiator and oil cooler.
Does the 4L80E have a converter plug?
Can you flush by removing the oil lines?
Any help muchly appreciated.

[redbird2]

Sorry to tell you there is no drain plug in the convertor, I have been using a flushing system to get all the fluid changed or 99% at least. If you don't have access to one of these machines most local dealers or quick change places have these here it will normally run $90 to $140 US to have trans serviced and this will included inter filter change along with flush and refill. The system I have used in the past will use 5 gallons on ATF during the flushing process.

here is how it works the pan is removed, the filter is removed, the line coming from the flush station connects where the filter inlet in to the trans case goes. large drain pan required can make large mess!!! the station is truned on the veicle is started and fresh fluid is pulled into the trans and old is flushed out, the reason for the large amount being used is it has to replace all the fluid in the convertor so basicly the more new you put in the less old that will be left in the trans and convertor you install new filter and reinstall pan fill pan restart check for leaks and recheck level all done.

I have made a mobile flush unit out of a 5 gallon bucket with a outlet pipe and valve on it then a length of hose with an adaptor to go into the filter inlet, I use gavity to feed the atf to the trans not a pump However this is used on step vans that have open access above the trans seems to work well

hope some of this helps

[sturgeon-phish]

The fluid changeout is easy. You may or may not have a drain plug on the pan. If you do, drain, if not remove the pan bolts except the four corners. Loosen them so you can tilt the pan drain fluid and remove. Remove the trans line to the cooler at the radiator. This will allow the lines and cooler to drain into the pan.
Keep the gasket. Put in a new filter, clean gasket and pan and tourqe to spec. Fill pan to fill line. Put a piece of tygon tubing over the trans line removed from the cooler line and secure the other end in a 5 gal bucket. Start the truck when it starts fluid will start coming out of the tubing into the bucket. Add fluid through the dipstick tube. When there is a color change in the fluid going in the bucket stop the truck. Remove tubing and secure line to trans cooler. Start truck, while stationary take through gears check level and add if needed. Take an easy drive check fluid anfer a day or two check fluid again.
While pan is off if you don't have a drain plug you may want to add one.
Jim

[glivingstone]

Thanks guys,
I am still a little confused, I have 2 X lines that go to the radiator and another 2 X lines that go to a cooler mounted in front of the condenser.
Do I only disconnect the line at the radiator or do I need to do something with the cooler as well?
No dealers to go to over here, at least none that know anything about these trucks.
Please keep the advice coming.

[DickWells]

:) Hi G-Stone:
I may catch heck in here for saying this, but as a die-hard DIY-r, I think the simpler way is the better way. IE, the second reply that you got. I've changed fluid in both the trans you see in my profile, and the 4L80E is the easier of the two. I didn't dis-connect at the cooler. I took off the return pipe at the transmission. It's the upper line, I think? Easy to find out, just start the engine with the line off. My reasoning is that you'll flush everything out as you go. If memory serves, I used about 18 quarts, total to change the fluid. Took 23 quarts in the Allison! I just had the old la- the little woman- start and shut down the engine, while I watched the oil. When I started getting air bubbles, I had her shut it off and I'd add a few quarts, then start it up again. A couple of times doing this and the fluid came out clear, and I called it a complete enough change. THEN, I re-installed the inlet pipe, topped off the fluid and road tested the Burb. Total cost was less than $80 for new filter,gasket and oil. It would have been more if I had used sythetic, like I did in the Allison.
BTW, I got the info to do this from right here in the DP several years ago.
I read back then, and I still believe, that it won't hurt the tranny to run free of oil for a short period, without a load, while you do this routine.
Give it a go, and good luck.
DW:)

[DickWells]

:o Whoops. Forgot. Two X lines at the radiator? One set is for engine oil cooling, the other for transmission. Transmission is on the right. But, it doesn't make much difference if you remove the return line at the transmission.
Save some time for working on those pesky engine oil cooler lines some other time, when they fall off, or start leaking! Just post a note, and we'll tell you some neat fixes.
DW:)