is Mobil 1™ Synthetic LV ATF HP compatible with dexron VI ATF?

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You can use the HP fluid and there is a GM bulletin that specifies the HP fluid replace the Dexron 6 in vehicles with shudder and other issues. I have already did this to around 30 GM SUV/Pickups ranging from 2015 thru 2018.
 
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I ran through the linked instructions with both trucks in my sig and it seems to work well. Thanks clinebarger!

My stock ramp table was a bit different so I just applied 150%+10psi to all columns 2-250 rpm.

Looks pretty good, Did you check the 3D graph to make sure the transitions are smoothed out?
 
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That's a '14 & up Pressure Ramp that I used as an example, But the same theory holds.

I modified a 2013 GMC Sierra TCC Pressure Ramp like I normally would.....The stock table looks identical to yours so it's safe to assume the calibration is pretty similar.

*Increased the 2 rpm & up by 50% (Multiplied by 1.50)
*Increased from 2 rpm to 200 rpm by 10 psi
*Smoothed the ramp in the 3D graph

In theory.....Smoothing the Ramp will decrease TCC Regulator Valve & Pressure Regulator "Shuttle". Pressure Regulator Valve wear is quite common on 6LxxE units so I believe any stabilization of pressure will only help.

Stock Ramp Table....
cj9A9Gg.png



Stock 3D Graph of the Table.....
wQNWDD2.png
 
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You can use the HP fluid and there is a GM bulletin that specifies the HP fluid replace the Dexron 6 in vehicles with shudder and other issues. I have already did this to around 30 GM SUV/Pickups ranging from 2015 thru 2018.

Didn't GM back off on that recommendation & now wants a thorough fluid exchange using Dexron VI on MYC-6L80E & MYD-6L90E?? Per Bulletin......#20-NA-142: Shudder/Surging While Driving - Revised Sep 13, 2021???
 
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Didn't GM back off on that recommendation & now wants a thorough fluid exchange using Dexron VI on MYC-6L80E & MYD-6L90E?? Per Bulletin......#20-NA-142: Shudder/Surging While Driving - Revised Sep 13, 2021???
You are probably correct as I have not had to check the system in awhile....but the procedure was working. I'm curious now and am going to check. Good catch
 
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That's a '14 & up Pressure Ramp that I used as an example, But the same theory holds.

I modified a 2013 GMC Sierra TCC Pressure Ramp like I normally would.....The stock table looks identical to yours so it's safe to assume the calibration is pretty similar.

*Increased the 2 rpm & up by 50% (Multiplied by 1.50)
*Increased from 2 rpm to 200 rpm by 10 psi
*Smoothed the ramp in the 3D graph

In theory.....Smoothing the Ramp will decrease TCC Regulator Valve & Pressure Regulator "Shuttle". Pressure Regulator Valve wear is quite common on 6LxxE units so I believe any stabilization of pressure will only help.

Stock Ramp Table....

Stock 3D Graph of the Table.....

You're right, I neglected to do any smoothing in my first attempt. Thanks for the detailed example; here's my second try.

Is this little hill in the stock calibration around the junction of 100rpm and 240 lb-ft the result of some characteristic of the engine's power band, or the lockup behavior of the torque convertor?

peak.jpg


smoothed graph

graph.jpg


table

smoothed.jpg
 
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That spike doesn't make any sense to me, If you look at my final graph, You'll see that I pulled the higher torque side of the spike up to smooth it (Red Circle)
 
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Interesting, would there be any disadvantage to making the ramp entirely flat? It looks like the 14' and up Ramp in the other thread specifies a constant pressure for all of the torque values (rows) for most of the RPM ranges (columns), but I suppose that might also be a different torque convertor in the newer models.

I can echo the sentiments in the other thread .. the new calibration is nice and firm, even sporty, without being harsh. Thanks again for the help :cool:


(note I have not tested this flattened out ramp in real life)

flat_chart.jpg


flat_table.jpg
 
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Dexron VI is the best fluid for the 6L80E unit, But NO fluid will save the Torque Converter Clutch from wearing out, I highly recommend having it tuned to eliminate the "Constant TCC Slip", While it's only a 10-20 rpm slip differential.....It creates a ton of heat at the Converter Clutch Lining, This breaks down the fluid as well.

Sure.....Changing the fluid often might prolong the inevitable, But will not stop it.


I've also tuned 8L90E units in a similar manner, It eliminates TCC "Bobble" even with Dexron VI. Leads me to believe that Dexron HP is a mere band-aid too get the unit through warranty, Unfortunately 8L90E Controllers have to be sent off to be Unlocked manually....Runs around a Grand to even access the controller(TCM) for tuning.

If you want to purchase HP-Tuners.....I can walk you through modifying the calibration. It will take @$500 to buy the Dongle & License a '17 5.3L/6L80E Silverado & you will need a Windows 10 Laptop.
I have a programmer Diablo sport trinity2 platinum. Can that be done with this or is this something else different ? I have a 2017 GMC Sierra 5.3 with the 8l90e. I haven’t noticed any shutter yet. I have 86k on my truck with a 7 inch lift and 35’s. I just bought 12 quarts of the blue label Mobil one. I was gonna do a tranny flush using this and then pump out the remaining fluid and fill with blue labe Mobil one. I understand why your talking about as it’s a band aid. It seems to me unless you replace the torque converter with say a circle D billet one the gm is gonna fail at some point reguardless the question is how long will it take and last.
F73F2E54-9F6A-4D62-9EC6-E28B85FAC5D3.jpg
 
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