10L90 Transmission Flush

Subzilla

Subzilla

Test Driver
Joined
Jun 13, 2011
Location
Triad - Mt. Pleasant, Concord & Georgeville
Just purchased a 2018 Tahoe with the 10 speed and 100k miles. Did research on fluid change. First off, no dipstick under the hood! Second, before y’all start bashing GM, this was a transmission designed by GM AND Ford collaboratively labeled as 10L90 by GM and 10L80 by Ford in their vehicles. Third, the fluid flush process is complex and requires special tools and a pump to refill at the trans plus the trans has to be at a certain temperature to check fluid level! Not an easy DIY project.
SO, anyone confident with this process that I can assist them with it? Or know a trustworthy shop or person that can handle it? I despise dealerships and am afraid of the average transmission repair shops. Had bad experiences with too many. I have a case of Amsoil fluid and filter and gasket waiting to go in.
 
A buddy of mine I use to work with many years ago at a GM dealership has his own shop in Rock Hill SC now (probably too far from you) but he was GM world class and is pretty sharp. He does tuning as well and did both my truck and our 13 Tahoe to remove cylinder deactivation and change the transmission tune and it's made a big difference. It's supposed to help save the transmission in these from destroying themselves and he may have a tune for that 10spd. I think those transmissions start locking up the converters in as low as 3rd gear and can give all sorts of chatter issues.
I'm not sure if he would be thrilled about "helping" him but if it's something you're interested in pursuing, I can give you his number.
 
Silverado_Express said:
A buddy of mine I use to work with many years ago at a GM dealership has his own shop in Rock Hill SC now (probably too far from you) but he was GM world class and is pretty sharp. He does tuning as well and did both my truck and our 13 Tahoe to remove cylinder deactivation and change the transmission tune and it's made a big difference. It's supposed to help save the transmission in these from destroying themselves and he may have a tune for that 10spd. I think those transmissions start locking up the converters in as low as 3rd gear and can give all sorts of chatter issues.
I'm not sure if he would be thrilled about "helping" him but if it's something you're interested in pursuing, I can give you his number
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You talking about AJ?
 
SubZilla, I'm glad you did all the research! I see the fluid change is the same as on my 8L90. But two things I question. First you have a 100k mile truck. Will this be the first or second time, changing the fluid? Trans guys have always said Do Not change a High mileage trans fluid, that hasn't had changes every 20-25K miles. You may flush out /wash out, all the trash accumulated in the torque converter. And that will kill the transmission! Second, my 8 speed, takes a Very Specific fluid. GM changed the formula 4 times to find one that Didn't cause torque converter clutch shudder. I know this applies to My 8 speed. I have no knowledge of the 10 speed. Btw, GM's fluids, are provided by Mobile 1.
 
Rodney. Yep, always heard about the high miles transmission fluid-don’t change thing too. I just got this thing so I have no idea if the fluid has been changed. So I am assuming this is the first change. I’m hoping that was more of an issue with the older transmissions but I really don’t know.
This transmission takes the ULV transmission fluid. I’m going to use Amsoil.
Mark
 
I've always heard change is ok, pressure flush is not. I had a car with the 6L whatever with no dipstick and had to check fluid from underneath, running, at a certain temperature. What a .....
 
LBarr2002 said:
I've always heard change is ok, pressure flush is not. I had a car with the 6L whatever with no dipstick and had to check fluid from underneath, running, at a certain temperature. What a .....
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100k imho isnt too high for a first fluid change anyway. I have changed many superdutys fluid around 100k and it doesn't look terrible and no problems after.
 
jeepyjman said:
I have changed many superdutys fluid around 100k and it doesn't look terrible and no problems after.
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Ditto... dropped the pan on mine to swap the TFT sensor, the fluid looking fine (a bit dull, but still red), and replaced 8 of 10 qts without any issues in the past 500 miles.
EXCEPT, it did cause the rear pinion seal to start spewing 🤣
 
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