Another Tranny Fluid Flush(replace) or Keep? Thread

[Wonderbread24]

My 2011 Yukon XL has got 178k on it. I bought it used from a private sale at the beginning of March. The price was right when we bought it I knew I had to do some work on it. One thing I forgot to look at was the tranny fluid condition. I didn't really think about it until I had to replace the radiator and noticed the fluid is extremely dark. So dark I was kind freaking out thinking there was oil in the tranny instead of ATF. After putting the paper towel to the dip stick is definitely brown and not red but smells like old burnt ATF and not oil.

I've talked to a few people and I've gotten mixed responses about what I should do. I've heard if the fluid is that far gone, changing the fluid will most certainly mean I will be buying a new/rebuilt tranny within a matter of weeks. Others have said leave it, pray, and start saving for a new tranny. Or people have told me to just change it.

I'm not sure what to do. Looking at the pan it appears to have a re-useable gasket so I'm thinking that it was taken care of up until the previous owner so I would be safe to change the fluid out. But then I'm freaking my self out because I definitely don't want to replace a transmission anytime soon. I don't have the budget for that right now.

I have no issues with it shifting currently. Its smooth as butter in stop and go traffic and on the freeway.

Should I replace the fluid or keep it? What is the consensus here on this forum?

 

[skpyle]

OK, changing the fluid is not going to have any affect on an impending failure of the transmission. Meaning, if it is ready to fail, it is going to fail soon enough. Not changing the fluid will not prevent this. Make any sense?

I am of the camp to always change the fluid. If the trans is going to fail, its going to fail. And you are out the cost of the fluid. Otherwise, fresh fluid is a good thing for the 6L80.

Ideally, drop the pan, replace the filter, and change the fluid. You are only going to get around 5 quarts out that way. That still leaves 7 or so in the torque converter. Look around on the internet for a brass fitting that connects into the upper transmission cooling line to your radiator. Get that, and a length of 3/*" ID vinyl hose. Buy 16qts of the cheapest Dexron VI you can find.

Remove the upper transmission cooling line from the radiator. Install the brass fitting and connect the vinyl hose. Run it into a jug or bucket. I used a 1 gallon jug. Start the engine, run it until the jug is approximately 3/4 full of old ATF. Stop the engine. Add 3 qts of new ATF to the transmission. DUMP THE JUG!!! I missed this step once...
Repeat this process until you have gone through all 16 qts of new ATF. The fluid coming out of the vinyl line at the radiator should be nice and red at this point. Put it all back together.
NOTE: there are plenty of write ups on this forum on how to exchange the transmission fluid. Don't just take my word. Search and see the ways others have done this.

Drive the truck and go from there. If the transmission fails, it was already on its way out, and you are out the cost of the ATF. And I will apologize. If it is good, then in around 10,000 miles, change the fluid again, this time putting in good quality Dexron VI.

Regardless of what you do, Good Luck!!

 

[Foggy]

IMO, Drop the pan. Clean everything up. Replace the filter.. Fill the trans
with fluid - 5-6 qts and drive on...
You'll see any debris or obvious impending doom evidence in the pan..
Now, saying that, the converter is the weak point on the 6l80e...
You won't be able to discern any info on this until there is too much wear.
When the clutch in the converter lets go it will spew shrapnel into the trans ..

 

[Geotrash]

+1 to both of these responses, but change the fluid at a minimum. I have mine done at a local oil change shop I trust who has the equipment to do the procedure that @skpyle described. It's called a fluid exchange, and not a fluid flush. Better yet, bite the bullet and have a transmission shop do the work, and have them also install a new, upgraded torque converter that has a billet housing and stronger lockup clutch. These are widely available from nationwide converter rebuilders and your shop can recommend one for you. This will prevent the problem that @Foggy described. I had this done on my 2012, along with the rear main seal on the engine at the same time, also with a new transmission filter, for $1400 out the door. Cheap insurance.

 

[donjetman]

Drop pan and clean it out, change fluid (6 qts Dexron VI) and filter with new.