2016 Yukon/L680 Transmission upgrades for HD TOW 2016 Yukon XL

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[NiamLeeSin]

I found some other older info about this:

"That is correct, It's cheaper to do a Billet Front Converter, TransGo Tow & Pro kit, And a trans tune/disabling the AFM NOW versus letting it fail."

https://bobistheoilguy.com/forums/threads/16-suburban-6l80-thermostat-update.360169/post-6247950

 

[tdebacker]

I have a 2017 Suburban Premier, also with the Max Tow Package. I pulled a 2500 lb empty trailer 18 hours from East Texas to Casper, WY and then had it loaded to a gross combined weight of 13,860 pounds another 7 hours south. After that trip, there's a few things I've been looking into:

-Circle D 300mm Torque Converter is a VERY important one. The factory torque converter kind of sucks.
-BlackBear tune to improve shift points, throttle response, and remove the "slip" between shifts the factory has planned.
-I'm soon going to install a Brian Tooley Racing Stage 1 VVT camshaft and upgraded valves springs along with an AFM Delete.
-Regearing to 3.73 would probably help as well. I want to do that, especially because I have 10 ply 33s.

The first two are the only transmission upgrades that I think you need, especially since you've already done the cooling upgrades. I'm not super knowledgeable about 6L80s, so there could be internal upgrades that I don't know about.

Mine has the Magneride with rear air suspension, so the ride and handling is awesome.

 

[NiamLeeSin]

I have a 2017 Suburban Premier, also with the Max Tow Package. I pulled a 2500 lb empty trailer 18 hours from East Texas to Casper, WY and then had it loaded to a gross combined weight of 13,860 pounds another 7 hours south. After that trip, there's a few things I've been looking into:

-Circle D 300mm Torque Converter is a VERY important one. The factory torque converter kind of sucks.
-BlackBear tune to improve shift points, throttle response, and remove the "slip" between shifts the factory has planned.
-I'm soon going to install a Brian Tooley Racing Stage 1 VVT camshaft and upgraded valves springs along with an AFM Delete.
-Regearing to 3.73 would probably help as well. I want to do that, especially because I have 10 ply 33s.

The first two are the only transmission upgrades that I think you need, especially since you've already done the cooling upgrades. I'm not super knowledgeable about 6L80s, so there could be internal upgrades that I don't know about.

Mine has the Magneride with rear air suspension, so the ride and handling is awesome.

Lots of really good info here, much appreciated.

Will you do most of this yourself? I'd love to be able to, but I don't see myself dropping the transmission. Or would you have a mechanic drop the transmission and swap the torque converter, and ship the techm to black bear for tune, then ship back?

Everyone I see at the campgrounds uses hd trucks to pull so it's great to hear from others using this model. I have the SLT, and have the magnaride as well and I love the safety features etc. The vehicle is perfect as a family car and for pulling the camper, so I really want it to work well so we can feel secure going cross country.

 

[NickTransmissions]

Lots of really good info here, much appreciated.

Will you do most of this yourself? I'd love to be able to, but I don't see myself dropping the transmission. Or would you have a mechanic drop the transmission and swap the torque converter, and ship the techm to black bear for tune, then ship back?

Everyone I see at the campgrounds uses hd trucks to pull so it's great to hear from others using this model. I have the SLT, and have the magnaride as well and I love the safety features etc. The vehicle is perfect as a family car and for pulling the camper, so I really want it to work well so we can feel secure going cross country.

What are your concerns or limitations around pulling the trans?

 

[NiamLeeSin]

What are your concerns or limitations around pulling the trans?

I'm not sure what the job entails. I have a copy of the service manual and will review, but I don't have a lift and transmission jack. My buddy has a quickjack I could use, but not sure that would work. Mainly I'm worried that I'll create leaks or damage a seal when I put it back together.

 

[NickTransmissions]

I'm not sure what the job entails. I have a copy of the service manual and will review, but I don't have a lift and transmission jack. My buddy has a quickjack I could use, but not sure that would work. Mainly I'm worried that I'll create leaks or damage a seal when I put it back together.

I believe I gave the details in another post earlier in this thread but here's a more consolidated list of steps:

- Jack up the vehicle and put it on all four jack stands or via Quickjack
- Disconnect harness, shift linkage cable and and cooler bypass valve / cooler lines and anything else that may be going to the trans from the rest of the vehicle.
- Remove the front exhaust
- Then put a trans jack underneath (these can be found at Harbor Freight for a couple hundred bucks)
- Index the driveline with a paint pen or marker so it goes back together exactly the same way it came off
- Remove the 4 bolts holding it to the pinion yoke then use a pry bar to free it from the yoke (pry towards the trans and down) then pull out out of the back of the trans (maybe have a catch pan as a small amt of fluid will likely come out)
- Put the trans jack underneath the trans to support it (if you have a 4WD, drain & remove the T-Case first - be careful not to damage the t-case encoder motor assembly bolted to the side of the Tcase)
- Remove the rear trans mount bolt(s) and rear transmission cross member (2WD)
- Remove the three bolts holding the torque converter to the flex plate (you will need to rotate the engine over to get to all three)
- Begin removing all the bell housing to engine block bolts (use a 24-36" 1/2 drive extension and wobble socket for the top bell housing bolt)
- Once all the bolts are out, use a pry bar to separate the trans from the engine
- Lower the trans jack w/trans and then roll out from under the vehicle
- Inspect the flex plate for cracks as well as the area behind it for rear main seal leaks (replace flex plate if cracked or rear main if leaking)

Installation is the reverse of removal. You wont hurt any seals if you're careful and you coat the front transmission seal with trans fluid before installing the torque converter. Coat the T-Case seal w/whatever fluid it takes if you have a 4WD before reinstallation. Transmission assembly lube also works very well ($5 per bucket).

You will only create leaks or damage seals if you're a gorilla about it.

There's plenty of youtube videos showing the process as well - you don't need a lift; the quick jack should work but if not, six-ton jack stands (i use two 12-tons for the front and two 6-tons for the rear).

Your main challenge is likely the same as most when it comes to DYI: finding the time.

 

[NiamLeeSin]

I believe I gave the details in another post earlier in this thread but here's a more consolidated list of steps:

- Jack up the vehicle and put it on all four jack stands or via Quickjack
- Disconnect harness, shift linkage cable and and cooler bypass valve / cooler lines and anything else that may be going to the trans from the rest of the vehicle.
- Remove the front exhaust
- Then put a trans jack underneath (these can be found at Harbor Freight for a couple hundred bucks)
- Index the driveline with a paint pen or marker so it goes back together exactly the same way it came off
- Remove the 4 bolts holding it to the pinion yoke then use a pry bar to free it from the yoke (pry towards the trans and down) then pull out out of the back of the trans (maybe have a catch pan as a small amt of fluid will likely come out)
- Put the trans jack underneath the trans to support it (if you have a 4WD, drain & remove the T-Case first - be careful not to damage the t-case encoder motor assembly bolted to the side of the Tcase)
- Remove the rear trans mount bolt(s) and rear transmission cross member (2WD)
- Remove the three bolts holding the torque converter to the flex plate (you will need to rotate the engine over to get to all three)
- Begin removing all the bell housing to engine block bolts (use a 24-36" 1/2 drive extension and wobble socket for the top bell housing bolt)
- Once all the bolts are out, use a pry bar to separate the trans from the engine
- Lower the trans jack w/trans and then roll out from under the vehicle
- Inspect the flex plate for cracks as well as the area behind it for rear main seal leaks (replace flex plate if cracked or rear main if leaking)

Installation is the reverse of removal. You wont hurt any seals if you're careful and you coat the front transmission seal with trans fluid before installing the torque converter. Coat the T-Case seal w/whatever fluid it takes if you have a 4WD before reinstallation. Transmission assembly lube also works very well ($5 per bucket).

You will only create leaks or damage seals if you're a gorilla about it.

There's plenty of youtube videos showing the process as well - you don't need a lift; the quick jack should work but if not, six-ton jack stands (i use two 12-tons for the front and two 6-tons for the rear).

Your main challenge is likely the same as most when it comes to DYI: finding the time.

Okay you talked me into it. You are correct about the DIY time constraints. Also the family can't fit in the secondary vehicle so we can't be without it for long.

 

[tdebacker]

Lots of really good info here, much appreciated.

Will you do most of this yourself? I'd love to be able to, but I don't see myself dropping the transmission. Or would you have a mechanic drop the transmission and swap the torque converter, and ship the techm to black bear for tune, then ship back?

Everyone I see at the campgrounds uses hd trucks to pull so it's great to hear from others using this model. I have the SLT, and have the magnaride as well and I love the safety features etc. The vehicle is perfect as a family car and for pulling the camper, so I really want it to work well so we can feel secure going cross country.

I'm HOPING to do all the work myself! There's a YouTube channel called Sundae Drive that has a LOT of informative videos about the DOD Delete on these specific engines. You have to remove the engine to do it all properly, and since it's out, might as well replace the converter since it's right there!

The gearing I'd have a shop do, but I don't know how to set valve lash, nor do I have any experience with gears.

For the tune, Black Bear sends you out a computer to scan and record how you drive and your vehicles stats when doing so, and then mails you a tune to download to the engine. Super easy.

You definitely don't need an HD truck to pull 6-8k pounds, but it does make you forget it's back there lol.

 

[NiamLeeSin]

I'm HOPING to do all the work myself! There's a YouTube channel called Sundae Drive that has a LOT of informative videos about the DOD Delete on these specific engines. You have to remove the engine to do it all properly, and since it's out, might as well replace the converter since it's right there!

The gearing I'd have a shop do, but I don't know how to set valve lash, nor do I have any experience with gears.

For the tune, Black Bear sends you out a computer to scan and record how you drive and your vehicles stats when doing so, and then mails you a tune to download to the engine. Super easy.

You definitely don't need an HD truck to pull 6-8k pounds, but it does make you forget it's back there lol.

Thank you. I reached out to Black Bear and they said my 2016 Yukon requires the Autcal V3 option. They said to swap the torque converter first if that's what I plan to do.