13 yukon Denali new owner drivetrain questions

[Hashiriya]

Hello, just a few question. 13 Yukon Denali 6.2 awd.
What transmission are these equipped with? I’ve done some research and I want to say it’s a 6l80 but I could be wrong.

Also. At 120k miles, I want to do a drain and refill of the trans fluid. Called the dealer when purchased and they had no history of ever doing any trans service or diffs, and I don’t want to do a flush and then my trans start slipping. I want to install a better trans cooler as well so what trans fluid and which cooler would you guys recommend?

Lastly, for the rear diff and front trasfer case, what gear oil would you guys recommend using.??
Any advice is greatly appreciated!
Thanks!!!!

 

[swathdiver]

If your trans is bad, it's bad, changing the fluid isn't going to cause it to fail. Change the fluid with Dexron VI and put the truck on the severe service schedule from now on.

75W90 full synthetic for both differentials. Dexron VI again for the transfer case.

Are you going to be towing? That little cooler is surprisingly efficient.

 

[Ibustbravo]

I'd take it to a transmission shop and have them give it a health check, it's usually free.

Here's the trans fluid type and the part # for a 6L80 ATF.

United States	Canada
Application	Type of Material	GM Part Number US/CAN
Automatic Transmission Fluid	DEXRON®VI	88861037	19264717

Front Drive Axle

Lubricant

Synthetic Gear Oil GM P/N 88900401 (GM Spec 9986115)

Canadian P/N 89021678

Axle Capacities
Front Axle 1000 Series (8.25”)	1.43 liters	1.51 quarts

Rear Axle (8.6/9.5/9.76 inch axles)	SAE 75W85 Synthetic Gear Oil	19300457 or equivalent meeting GM Specification 9986375	19300458 or equivalent
Rear Axle (10.5,11.5 inch axles)	SAE 75W90	88900401 or equivalent meeting GM Specification 9986115	89021678 or equivalent
Rear Axle Housing Spindle	SAE 75W90	88900401 or equivalent meeting GM Specification 9986115	89021678 or equivalent

C

 

[Geotrash]

Hello, just a few question. 13 Yukon Denali 6.2 awd.
What transmission are these equipped with? I’ve done some research and I want to say it’s a 6l80 but I could be wrong.

Also. At 120k miles, I want to do a drain and refill of the trans fluid. Called the dealer when purchased and they had no history of ever doing any trans service or diffs, and I don’t want to do a flush and then my trans start slipping. I want to install a better trans cooler as well so what trans fluid and which cooler would you guys recommend?

Lastly, for the rear diff and front trasfer case, what gear oil would you guys recommend using.??
Any advice is greatly appreciated!
Thanks!!!!

+1 on doing a transmission fluid exchange. It will prolong the life of the unit on these. At 120K, if it hasn't been replaced already, you're likely to have the torque converter fail and take the transmission with it within the next 30-40K max. It would be money well-spent to replace yours with one that has a billet cover and a stronger lockup clutch. The lockup clutch eats itself over time, and was criminally thin from the factory anyway, so when (not if) it finally eats through the friction material, it will send fine metallic shrapnel through the transmission and coolers.

I second the recommendation to leave the factory transmission cooler as it is. I tow a 7500 lb camper with mine and after messing around with aftermarket coolers I learned that the factory setup has plenty of margin for towing in hot weather and would stay with it if I had it to do over again. Lots of guys put a Tru-Cool 40K in front of their radiator in place of the factory cooler, but on the Denali it creates a cooling problem for the engine, as I learned first-hand. The 6.2 generates more heat than the 5.3 so the radiator is closer to its limits and dumping so much more heat in front of it over a larger area with the Tru-cool, causes coolant temp to rise to uncomfortable levels when towing, sometimes triggering the warning chime.

If it ain't broke...

 

[petethepug]

Welcome, congrats on getting the beast outfitted with all the accoutrements of the later model year trucks. You got the 6L80 6SP. They’re good for 300k if they’re flushed every 100k.

Here’s the crossroad your at … if the trans, diff’s & xfer case haven’t been serviced, it’s a do it now and pay for labor and fluid or … do it later and pay for labor and trans rebuild. A new trans is $5k+ min and the 100k major service for AWD is $1k+ min.

The other fork at the road is if you discover a leaking pan gasket or rear main seal. The pan gasket job is a breeze with the trans out because all its bolts are 150% accessible. You can also have a new 97¢ o ring installed on n the oil pump know to fail and cause oil pressure failure.

The trans comes out for the $25 rear main seal kit. Labor is the killer, but … at that point though, your high labor costs for other known AWD failure components becomes almost free.

The following will be touched, removed be given access for effortless change out if an AWD trans is removed.

* torque converter upgrade replacement.
* engine rear main seal.
* engine pan gasket.
* engine oil pump o ring.
* trans rear output seal.
* front diff & xfer case fluid swap.
* trans fluid service.
* motor mounts (both!)
* exhaust mani gaskets.
* exh mani bolt upgrade to ARP.
* repair or replace trans cable end.
* engine oil pressure sensor.
* L/R front diff mount bars (w/ new bushings).
* F/R sway bar bushes. Recom upgrade to poly.

The kicker here is the cost of OEM parts for the oil press sensor, motor mounts & pan gasket. If you buy them from Rock Auto you’ll save 50-80% over what the dealer or local Indi will have to pay locally. My Indi tech recommended I do this when my trans was being replaced and it was only $1.5k for all the above items to be ordered & installed. The trans rebuild and labor was $5k.

It’s pay now or pay later. I’m good for another 100k on the drive train of my 09 AWD. It drives better than new. Keep in mind the dealer will getcha for $1.5k just to replace the L/R motor mounts on an AWD.

 

[blackelky]

I wonder if it is any good to change the transmission filter? My dealer says they do a reverse flush that cleans the filter too

 

[swathdiver]

I wonder if it is any good to change the transmission filter? My dealer says they do a reverse flush that cleans the filter too

I changed my filter for the first time at 184K and could have left it in much longer. Dealership did a fluid exchange the first time, we did it the other times.