18 6L80 Fluid Change

[bayouguy71]

I just hit 36k and have nice long trip coming up towing our camper at about 6500lbs fully loaded.

 

Prior to our trip in about 4 weeks I want to get my "pill flipped" to keep the trans temps down this time.

 

This will be the 2nd time towing this camper 6+ hrs and the 3rd time overall the truck has has a pretty good workout (towed RZR / ACE to West Virginia) 2 years ago so I am calling my truck severe use

 

With that said, dealership quoted $220 for trans "flush" and filter change and after watching the video(s) they can have my money, I don't want to mess with that.

 

On the other hand I am thinking of switching to Redline or Amsoil and do the same procedure to get as much of the old stuff out as possible.

 

Can any reputable shop "pump" out the old and fill with whatever fluid I bring them?

 

I know it is still under powertrain warranty so do I just have GM do it in case there are issues down the road or go for it with better fluids?

 

 

[Grumpy Bear]

Couple of things here. Flipping the pill will help day in and day out. Towing is a question yet to be answered. That depends on load vs cooler capacity. Day in and day out you have 'extra'...not sure about the tow. 

 

36K change is GREAT. 

 

Both fluids mentioned are very good. Both will take more heat. Both will shed more heat. How much more depends some on what percentage of the fluid gets changed. Max is about 12-15% more BTU's. That will translate to about 8-10F fluid temperature reduction for the 'same' load. It's had to get an apples to apple run. 

 

Suppose GM said 'only park your truck in a garage with a paper roof or your warranty will be void. It hails where you live allot. You think a steel roof would be better protection. Your neighbor says, 'But your warranty will be void"! Give that some thought...  Then apply that to your fluids. 

 

 

[bayouguy71]

I was hoping you would chime in Grumpy and you gave the answer(s) I expected.

Now the question is, how many places will pump out the old and put in the new.

I want to get as much fluid out as possible the first time.

Watching the videos these guys are getting 8-10 quarts out by pumping and then doing the pan.

With the pill flipped you don't have to worry about operating temp to pump fluid right?

 

[Black02Silverado]

Here at least the dealer will do the fluid exchange for $100 if I provide the AMSOIL fluid.  This is what I have had done on our 2016 Suburban and had done on my 2002 Silverado back in 2002.  But if I knew then what I know know about the 2002 I would have done it myself.  A lot easier, especially since the grill on the 2002 was super easy to take off and to get to the cooler line.

 

So you might want to check with the dealer and see if they offer the same.

[Grumpy Bear]

2 hours ago, bayouguy71 said:

I was hoping you would chime in Grumpy and you gave the answer(s) I expected.

Now the question is, how many places will pump out the old and put in the new.

I want to get as much fluid out as possible the first time.

Watching the videos these guys are getting 8-10 quarts out by pumping and then doing the pan.

With the pill flipped you don't have to worry about operating temp to pump fluid right?

 

 

With the pill flipped you will find the upper hose at the transmission is "out" and yes, temperature is no longer a concern. Measure what you pump out and replace the exact same amount. 

 

I did drop and fill. 6 quarts first time with filter. Second time I replaced the pan with a PML 8 quart unit with a drain plug. After that, just drain and fill 8 quarts at a time. PML also has a stock volume pan with a drain. (6 quarts). Some guys weld in a bung and drain at the pans deepest point. If you stay at 6 quarts and the system holds basically 12 quarts then each change dilutes by 50% per change. 

 

1st change is 50% new fluid

2nd change is 75%

3rd change is 87.5%

4th change is 93.75% (The Lions share) 

5th change is 96.875%

6the change is 98.4375% (Statistically considered fully converted) 

7th change is 99.21875%

8th change is 99.609375% (Okay this is getting silly  )

 

200 miles between fills for mixing is plenty. Be patient. Or do it at each oil change as part of normal maintenance. Once you reach a percentage that makes you happy a drain and fill every 25 to 35K is good. 

 

 

 

 

Edited May 5, 2021 by Grumpy Bear

[BlaineBug]

My local service department told me that their standard flush does not remove the pan.  So you totally miss out on cleaning the pan, replacing the filter, cleaning the magnet unless you pay them even more.

[Black02Silverado]

33 minutes ago, BlaineBug said:

My local service department told me that their standard flush does not remove the pan.  So you totally miss out on cleaning the pan, replacing the filter, cleaning the magnet unless you pay them even more.

Yes, that is extra.  But I did mine early, like at 10k miles just about still new.  So with the fluid exchange I had pretty much close to 100% new AMSOIL fluid and wasn't worried about the filter.  Now at 50K miles I did drop the pan and changed out the filter and cleaned up the magnet and pan.  It looked great.  Then I just topped back off what came out with the pan drop and I will do it again at 100k miles.

[BlaineBug]

1 minute ago, Black02Silverado said:

Yes, that is extra.  But I did mine early, like at 10k miles just about still new.  So with the fluid exchange I had pretty much close to 100% new AMSOIL fluid and wasn't worried about the filter.  Now at 50K miles I did drop the pan and changed out the filter and cleaned up the magnet and pan.  It looked great.  Then I just topped back off what came out with the pan drop and I will do it again at 100k miles.

What is the "new revised" recommended fluid for the 6 speed used in 2019 Yukon's?  Is that Dexron VI?  What's the Amsoil recommendation?

I'm at 40,000 now and want to go through all fluids, both differentials, transfer case, and transmission.  If I'm not mistaken the manual calls for the same transmission fluid to be used in the transfer case as well.  Thank you.

PS, I don't have any torque converter shutter issues, but I heard that there was a "new, revised GM fluid" that was supposed to cure that if you had that problem.

[BlaineBug]

Or am I mistaken and Mobil 1 Synthetic LV ATF HP is the revised/recommended fluid used?

[newdude]

1 hour ago, BlaineBug said:

What is the "new revised" recommended fluid for the 6 speed used in 2019 Yukon's?  Is that Dexron VI?  What's the Amsoil recommendation?

I'm at 40,000 now and want to go through all fluids, both differentials, transfer case, and transmission.  If I'm not mistaken the manual calls for the same transmission fluid to be used in the transfer case as well.  Thank you.

PS, I don't have any torque converter shutter issues, but I heard that there was a "new, revised GM fluid" that was supposed to cure that if you had that problem.

 

40 minutes ago, BlaineBug said:

Or am I mistaken and Mobil 1 Synthetic LV ATF HP is the revised/recommended fluid used?

 

 

There is no "revised fluid" for 6 speeds, they use Dexron 6.  

 

Mobil 1 LV ATF HP is for 8L45/8L90 ONLY.  

Edited May 5, 2021 by newdude

[Grumpy Bear]

51 minutes ago, BlaineBug said:

What is the "new revised" recommended fluid for the 6 speed used in 2019 Yukon's?  Is that Dexron VI?  What's the Amsoil recommendation?

I'm at 40,000 now and want to go through all fluids, both differentials, transfer case, and transmission.  If I'm not mistaken the manual calls for the same transmission fluid to be used in the transfer case as well.  Thank you.

PS, I don't have any torque converter shutter issues, but I heard that there was a "new, revised GM fluid" that was supposed to cure that if you had that problem.

 

https://gmauthority.com/blog/gm/gm-transmissions/myc/

 

All RPO code MYC take Dexron VI

 

https://gmauthority.com/blog/gm/gm-transmissions/m5u/

 

All 8L90E RPO code M5U use Dexron High Performance ATF

 

https://www.dieselhub.com/trans/10r80-10l80.html

 

The 10 speeds use MERCON/DEXRON ULV ATF

 

[Black02Silverado]

3 hours ago, BlaineBug said:

What is the "new revised" recommended fluid for the 6 speed used in 2019 Yukon's?  Is that Dexron VI?  What's the Amsoil recommendation?

I'm at 40,000 now and want to go through all fluids, both differentials, transfer case, and transmission.  If I'm not mistaken the manual calls for the same transmission fluid to be used in the transfer case as well.  Thank you.

PS, I don't have any torque converter shutter issues, but I heard that there was a "new, revised GM fluid" that was supposed to cure that if you had that problem.

The recommended fluid for your transmission is AMSOIL's ATL fluid. This also works in your transfer case.  I changed my 2019 over at 500 miles both front and rear diff's and transfer case.   The transmission being a 10sp and no dipstick, I have not done yet but plan on it some time here soon.

 

The squeeze packs make differential and t-case changes easy and clean. 

Edited May 5, 2021 by Black02Silverado

[bayouguy71]

17 hours ago, Black02Silverado said:

Here at least the dealer will do the fluid exchange for $100 if I provide the AMSOIL fluid.  This is what I have had done on our 2016 Suburban and had done on my 2002 Silverado back in 2002.  But if I knew then what I know know about the 2002 I would have done it myself.  A lot easier, especially since the grill on the 2002 was super easy to take off and to get to the cooler line.

 

So you might want to check with the dealer and see if they offer the same.

Well, I asked my dealer this very question and she was happy to give me basically the same cost as if they were providing the fluid AND then proceeded to tell me my powertrain warranty would be void by not using GM fluids.

 

[BlaineBug]

Thank you newdude, Grumpy Bear, and Black02Silverado!  Just over 40,000 now so within the next month or 2 will be changing transmission, transfer case, and both differentials for peace of mind.

[BlaineBug]

2 hours ago, bayouguy71 said:

Well, I asked my dealer this very question and she was happy to give me basically the same cost as if they were providing the fluid AND then proceeded to tell me my powertrain warranty would be void by not using GM fluids.

 

Yes that's corporate policy.  Do it yourself (OR go to a reputable small mechanic shop that won't report to GM) and then if something fails, don't say a word, OR in your service log indicate you used the OEM fluid.  Obviously the AMSOIL fluid won't destroy the transmission but it's best not to let them know as there is "fine print" for situations like this with some "unknown variable" such as non-OEM fluids which will void your warranty coverage.

Replace the fluid as you wish but don't enter into your log that you use AMSOIL fluid.  If I recall there was some court case that ruled self-service and user maintenance was not enough to void an automotive factory warranty in the event of a failure.  But obviously using any non-OEM part or product will void a warranty because there such an array of crappy parts out there.  If you tried to litigate it you'd probably be in for more than the cost of a new factory transmission anyway, figuring $250-$300 per hour in attorneys fees plus court costs and other BS expenses fighting it with General Motors to prove that AMSOIL had no bearing on transmission failure.

Edited May 5, 2021 by BlaineBug