Automatic transmission fluid and differentials

[12iotman]

I just joined the family with a 2019 yukon xl 5.3. In the progress of making sure the truck will last for a long time. That being said, I'm looking to change out transmission fluid and the transfer case. After reading through here and various other sites, I learned I will need about 3.5 gallons of DEXRON-VI Automatic Transmission Fluid along with getting a filter.

I am wondering as far as the front/rear differentials is the job as hard as the ATF. Also what is the correct fluid and amount for it? THank you all!

 

[OR VietVet]

Welcome to the forum from Oregon

 

[Bill 1960]

Welcome. Diffs are easy; scraping the old gasket off is the hardest part. I’m a fan of LubeLocker reusable gaskets myself. No more scraping off paper and no messing around with RTV.

 

[Rocket Man]

Just make sure you can remove the fill plugs before you drain the diffs. Sometimes they're rusted if you're in that part of the country and you cant get them out. Don't drain the fluid if you can't refill it!

 

[gooffeyguy]

Better yet, buy aftermarket covers that have a fill and drain plug

 

[Bob2C]

These are great videos. I watched them before doing mine. I reused the gasket for the trans and rear end. No issues 20k miles later.

(6L80)

(8L90)

(differentials and transfer case)

 

[12iotman]

Thank you all for the info. Using amsoil's site to get specification and capacity, it mentioned the following:

Automatic Transmission, 6L80 Initial Fill..........6 quarts
Automatic Transmission, Total Fill
6 speed W/O HDC 6L80..........12.2 quarts
6 speed W/ HDC 6L80..........12.4 quarts
Differential, 8.6 RingGear Rear..........4.2 pints
Differential, 9.5 RingGear Rear..........5.5 pints
Differential, 9.76 RingGear Rear..........5.5 pints
Differential, 8.25 RingGear Front..........3 pints

I scanned my QR code containing my RPO code and it showed the following:
2019,TK15906,11,18,06,WHTXVW, AG2 AN3 ARL AXP AYQ CF5 CJ4 C6H DD8 DL3 EF7 FE9 FHS GU4 G80 G9K H2X IO6 I19 JD9 KG4 L83 MAH MYC NP5 NTB RC4 RKX RUF TC2 UDD UHN UQA U2K V8D WMK ZW7 Z82 Z88 4AA 4SA 6SH 7SH 8X2 9X2,464C

I'm assuming since my yukon is a 5.3, it doesn't have HDC (which i assume is hill descent control?) I cant find anything about ring gear for the differential or should i just resort to doing 75w-90 all around for the differentials and just top it off until it starts pouring out of the fill plug. Also, I know the rear requires a gasket but I want to make sure the front is simply draining and filling with no need to take any pans off like the ATF and rear differential.

Thank you again.

 

[OR VietVet]

GU4=3.08 gears. G80=limited slip differential.

8.6 Ring and Pinion and is a 10 bolt cover.

IMO, I always defer to what my manual says and I use GM fluids. Any quality substitute should be fine.

 

[Bob2C]

Thank you all for the info. Using amsoil's site to get specification and capacity, it mentioned the following:

Automatic Transmission, 6L80 Initial Fill..........6 quarts
Automatic Transmission, Total Fill
6 speed W/O HDC 6L80..........12.2 quarts
6 speed W/ HDC 6L80..........12.4 quarts
Differential, 8.6 RingGear Rear..........4.2 pints
Differential, 9.5 RingGear Rear..........5.5 pints
Differential, 9.76 RingGear Rear..........5.5 pints
Differential, 8.25 RingGear Front..........3 pints

I scanned my QR code containing my RPO code and it showed the following:
2019,TK15906,11,18,06,WHTXVW, AG2 AN3 ARL AXP AYQ CF5 CJ4 C6H DD8 DL3 EF7 FE9 FHS GU4 G80 G9K H2X IO6 I19 JD9 KG4 L83 MAH MYC NP5 NTB RC4 RKX RUF TC2 UDD UHN UQA U2K V8D WMK ZW7 Z82 Z88 4AA 4SA 6SH 7SH 8X2 9X2,464C

I'm assuming since my yukon is a 5.3, it doesn't have HDC (which i assume is hill descent control?) I cant find anything about ring gear for the differential or should i just resort to doing 75w-90 all around for the differentials and just top it off until it starts pouring out of the fill plug. Also, I know the rear requires a gasket but I want to make sure the front is simply draining and filling with no need to take any pans off like the ATF and rear differential.

Thank you again.

I used AMSOIL Severe gear 75-90 in the front and rear diff. The rear diff gasket is reusable and bolt torque is 27ftlbs. Just fill until it starts coming out the fill hole. When you have the cover off there is a magnet stUck to the bottom of the housing that needs to be cleaned as well as the cover. Just like the video I spayed the inside of the case and all the gears down with brake cleaner. I wanted to remove the black film. It will mostly drain but there was a little left that I just soaked up with a rag. I let the case air out for about 30 min just to make sure the brake cleaner evaporated completed. Maybe a little OCD.

The front diff is drain and fill only. Just remember like others have mentioned to remove the fill plug first. It can be frozen to the case being a steel plug. I sprayed mine with wd40 while worked on the rear. Your going to have to remove the plastic shield under the engine to do the front. I did spay brake cleaner in the fill hole and worked the plastic tube around to get it cleaned out. It ran black for a while then cleared up. This time I waited a bit then squeezed some gear oil in with drain plug out just to make sure there wasn’t any sitting brake cleaner. Again fill until just starts to come out fill plug

The transfer case take ATF fluid and it’s the same. Drain and fill. Do take note when removing the fill plug first if you get a lot of fluid coming out. If that happens the seal between the transfer case and transmission is shot. I don’t think you’ll have a problem being new but just something to watch for.

if you go with AMSOIL get the squeeze packs of gear oil for the diff’s. Also get the correct quantity for the transfer case as well in ATF. It makes the job sooo much easier IMO.

 

[12iotman]

I used AMSOIL Severe gear 75-90 in the front and rear diff. The rear diff gasket is reusable and bolt torque is 27ftlbs. Just fill until it starts coming out the fill hole. When you have the cover off there is a magnet stUck to the bottom of the housing that needs to be cleaned as well as the cover. Just like the video I spayed the inside of the case and all the gears down with brake cleaner. I wanted to remove the black film. It will mostly drain but there was a little left that I just soaked up with a rag. I let the case air out for about 30 min just to make sure the brake cleaner evaporated completed. Maybe a little OCD.

The front diff is drain and fill only. Just remember like others have mentioned to remove the fill plug first. It can be frozen to the case being a steel plug. I sprayed mine with wd40 while worked on the rear. Your going to have to remove the plastic shield under the engine to do the front. I did spay brake cleaner in the fill hole and worked the plastic tube around to get it cleaned out. It ran black for a while then cleared up. This time I waited a bit then squeezed some gear oil in with drain plug out just to make sure there wasn’t any sitting brake cleaner. Again fill until just starts to come out fill plug

The transfer case take ATF fluid and it’s the same. Drain and fill. Do take note when removing the fill plug first if you get a lot of fluid coming out. If that happens the seal between the transfer case and transmission is shot. I don’t think you’ll have a problem being new but just something to watch for.

if you go with AMSOIL get the squeeze packs of gear oil for the diff’s. Also get the correct quantity for the transfer case as well in ATF. It makes the job sooo much easier IMO.

Wow thank you and everyone else for the info. Hopefully this truck will last for a long time. Thanks again!