GM 8 speed Transmission Flush

[buster]

So I took the truck to the dealership and specifically requested a flush. Instead, they dropped the pan, replaced filter and gasket. They added 6qts back in. I asked the service writer if they used Mobil 1 LV. He had no idea. The part number on the invoice is 19421242, which is listed as discontinued AC Delco.

19421242 - Genuine GM FLUID,A/TRANS DEXRON VI ACDELCO BULK OPT1

GMPartsGiant.com offers the great deal for genuine GM parts, 19421242. FLUID,A/TRANS DEXRON VI ACDELCO BULK OPT1. All parts are backed by the GM's warranty.

www.gmpartsgiant.com

I went to the parts guy to have him check. He said it was Mobil 1 LV based on the bulk part number he cross-referenced. Other opinions from the FB group suggested it could be the older dex VI and not LV. Kind of a let's get rid of this old fluid type of thing....or, the part number is old and not matching.

I'm going to call tomorrow to confirm. If it turns out they put in older fluid I'm going to have them flush it out and put Mobil 1 LV in. You'd think by now they'd have this down being the headache that it was for them.

 

[silversport]

good luck Buster...I can't imagine by this time that any GM dealership would still have any of the old stuff especially if they are doing the change under warranty...

Bill

 

[buster]

good luck Buster...I can't imagine by this time that any GM dealership would still have any of the old stuff especially if they are doing the change under warranty...

Bill

Thanks. @The Critic informed me it was the correct fluid.

 

[JTK]

So I took the truck to the dealership and specifically requested a flush. Instead, they dropped the pan, replaced filter and gasket. They added 6qts back in. I asked the service writer if they used Mobil 1 LV. He had no idea. The part number on the invoice is 19421242, which is listed as discontinued AC Delco.

The exhaust crossover has to be dropped on these trucks to drop the pan. Just curious if they also had to charge for new bolts, gaskets, etc.

Do aftermarket pans with a drain plug exist? After that first ~30K pan drop and cleaning, I'd be good with just spills and fills from then on if you had a drain plug. Cooler line fluid exchanges being best obviously.

I do know in 2018+ Traverse world, 9T65 owners effected with TC shudder, have stopped it by changing over to M1 blue label Dex VI as well. Others have stopped it by just adding a bottle of LG red. Luckily my 2021 was smooth as butta when we bought it with 30K miles on it. I've done 3 spill/fills with "suitable for dex VI fluid use" just to get the darkened factory fluid out of there anyway.

 

[Snagglefoot]

I find my local dealership wants to do a full flush instead of just a pan drop alone. Weird.

For regular service the owners manual doesn’t even suggest a transmission service, ever. For severe service suggests a service ever 45,000 miles, and even so, it’s just a “ change fluid and filter” which is basically a pan drop. Sounds like a mechanic who doesn’t care what the service writer puts on the form.

 

[buster]

I find my local dealership wants to do a full flush instead of just a pan drop alone. Weird.

For regular service the owners manual doesn’t even suggest a transmission service, ever. For severe service suggests a service ever 45,000 miles, and even so, it’s just a “ change fluid and filter” which is basically a pan drop. Sounds like a mechanic who doesn’t care what the service writer puts on the form.

View attachment 216924View attachment 216925

Yeah it's kind of weird actually. I requested flush, but they did a pan drop/filter/gasket change. I'm ok with that.

The service manager confirmed with the tech that the right fluid was used. They have a huge bulk drum of the Mobil 1 LV fluid (or AC Delco HP version). What happened was the service tech used an old part number. So I was undercharged a bit bc the M1 fluid is more expensive. He said I could come in and have the invoice updated to reflect it or they will have it changed if I wanted to.

I will request a flush next time and make sure it's a flush and not pan/filter change. I'm glad the filter was changed though to get the OE wear metals out.

I want to stay on top of the ATF in this truck being they were prone to shudder issues. The 22's have a new torque converter which may or may not help. Time will tell.

There are some guys, even those with 2018's, that never have a problem. It's a very smooth shifting transmission. I like it a lot. I'm tempted to get the truck tuned as it could help prolong the life of the transmission.

 

[buster]

....it's always someting...

 

[buster]

The dealer closer to me said they normally use the machine and do a flush ($399). Rarely do they drop the pan. Interesting. The dealer I got the truck from said on the trucks they normally do pan drops.

 

[The Critic]

The dealer closer to me said they normally use the machine and do a flush ($399). Rarely do they drop the pan. Interesting. The dealer I got the truck from said on the trucks they normally do pan drops.

Pan drop pays better.

 

[Snagglefoot]

Thanks. @The Critic informed me it was the correct fluid.

Just curious. Doesn’t this vehicle, with its 8 speed transmission require Dexron HP and not Dex VI?

 

[buster]

Yes.

For more clarification:
TCC Shudder and New Mobil 1 Fluid Exchange
January 31, 2019
A new transmission fluid exchange procedure and a new formula of Mobil 1 Synthetic LV ATF HP transmission fluid have been released to address torque converter clutch (TCC) shudder conditions on 8L45 and 8L90 8-speed automatic transmissions
..............
The TCC shudder condition is related to moisture content in the transmission fluid. The current fluid tends to be hydroscopic, or absorbs moisture, which increases the chance of TCC shudder. There are three different fluid exchange procedures to follow, depending on vehicle application, so that an acceptable concentration of the new HP fluid is achieved in the transmission.
....................
The new Mobil 1 Synthetic LV ATF HP transmission fluid is now available to U.S. dealerships through your local GM Oil Distributor. The new Mobil 1 Synthetic LV ATF HP transmission fluid is available in quart bottles (GM Part Number 19417577) and, for a limited time, in 55-gallon drums (GM Part Number 19417904)

 

[Snagglefoot]

Yes.

View attachment 216949

So the stuff the dealer put in was Dex VI and not Dexron HP?

 

[buster]

So the stuff the dealer put in was Dex VI and not Dexron HP?

No they put in Mobi 1 LV HP.

The service tech wrote the wrong part number on the invoice. So I lucked out and saved a few $ as result.

 

[clinebarger]

I'm tempted to get the truck tuned as it could help prolong the life of the transmission.

Requires the TCM to be unlocked, ALL '17 & up T87A 8 speed & 10 speed controllers do before any actual TCM tuning can be done.

Most buy a new unlocked-programmed module from HP-Tuners.

 

[PontiacHO]

This is what I use. The same amount of fluid replaced as a pan drop. If the filter is dirty, the trans is junk anyway. Changing it won’t help. I do it twice. Draw it out, refill, and drive 5 miles. Come back, repeat. No exhaust etc to fight.

Manual Oil Changer, 6.9 Quart | West Marine

Check out our Manual Oil Changer, 6.9 Quart and more from West Marine!

www.westmarine.com

 

[michaelluscher]

This is what I use. The same amount of fluid replaced as a pan drop. If the filter is dirty, the trans is junk anyway. Changing it won’t help. I do it twice. Draw it out, refill, and drive 5 miles. Come back, repeat. No exhaust etc to fight.

Manual Oil Changer, 6.9 Quart | West Marine

Check out our Manual Oil Changer, 6.9 Quart and more from West Marine!

www.westmarine.com

I'm considering a pneumatic version of the same tool
Make pan drops less messy, or avoid them on non drain plug equipped units