2016 Yukon Transmission Shudder

[Borrowed_Time068]

Good morning. First time poster here. I did read some past threads on this issue. But am looking for some recommendations .

Bought a CPO 2016 Yukon with 75k mikes in 2019. Of course, shortly after the warranty expired things started to go wrong. (AC broke twice) Now, with 103k on it, the 6 speed transmission has started that common shuddering issue which I’m fairly certain is the torque converter as referenced in the TSB. About 10k ago, I had the transmission pan dropped, filter and fluid replaced. Fluid looked good at that time.

I happen to live near a very reputable transmission shop that has done work for me in the past. But should I take it to an actual dealership first for the diagnosis? I read there is a possible law suit against GM on this. Thank you.

 

[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.

I cannot personally help you with your question; however, other members on this Forum that are much more knowledgeable than me in this area will chime in.

@NickTransmissions can give you some great perspective on your issue.

 

[Borrowed_Time068]

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.

I cannot personally help you with your question; however, other members on this Forum that are much more knowledgeable than me in this area will chime in.

@NickTransmissions can give you some great perspective on your issue.

 

[Borrowed_Time068]

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.

I cannot personally help you with your question; however, other members on this Forum that are much more knowledgeable than me in this area will chime in.

@NickTransmissions can give you some great perspective on your issue.

Thank you! I am in Massachusetts. Unfortunately

 

[NickTransmissions]

Good morning. First time poster here. I did read some past threads on this issue. But am looking for some recommendations .

Bought a CPO 2016 Yukon with 75k mikes in 2019. Of course, shortly after the warranty expired things started to go wrong. (AC broke twice) Now, with 103k on it, the 6 speed transmission has started that common shuddering issue which I’m fairly certain is the torque converter as referenced in the TSB. About 10k ago, I had the transmission pan dropped, filter and fluid replaced. Fluid looked good at that time.

I happen to live near a very reputable transmission shop that has done work for me in the past. But should I take it to an actual dealership first for the diagnosis? I read there is a possible law suit against GM on this. Thank you.

Welcome to the forum.

Shudder is almost always torque converter and specifically, the shuddering is coming from the stator one-way clutch inside the converter that is supposed to be holding during torque multiplication until fluid coupling (aka stall speed) is achieved.

The 8L45s/90s were/are the subject of a class action lawsuit against GM for failing, leading to accidents and unsafe situations (super hard, back-breaking shifts, etc) for people driving those vehicles at the time of failure. I'm not aware of any lawsuits for the 6L transmissions but wouldn't be surprised in the least if some are on-going as the TC is one of the four most prolific failure points in the 6L45,50,80 and 90 transmissions. The converter clutch is .020" thick which is way undersized.

Your transmission shop should have no problems diagnosing the concern (just tell them what you wrote here and that should be sufficient). They will likely recommend a complete overhaul as when the converter fails, it typically contaminates the rest of the unit and scores up the pump pretty bad. Figure to pay between $3000-4500 for a bench build and $5000+ if you have the transmission shop remove and reinstall it as well.

 

[Borrowed_Time068]

Welcome to the forum.

Shudder is almost always torque converter and specifically, the shuddering is coming from the stator one-way clutch inside the converter that is supposed to be holding during torque multiplication until fluid coupling (aka stall speed) is achieved.

The 8L45s/90s were/are the subject of a class action lawsuit against GM for failing, leading to accidents and unsafe situations (super hard, back-breaking shifts, etc) for people driving those vehicles at the time of failure. I'm not aware of any lawsuits for the 6L transmissions but wouldn't be surprised in the least if some are on-going as the TC is one of the four most prolific failure points in the 6L45,50,80 and 90 transmissions. The converter clutch is .020" thick which is way undersized.

Your transmission shop should have no problems diagnosing the concern (just tell them what you wrote here and that should be sufficient). They will likely recommend a complete overhaul as when the converter fails, it typically contaminates the rest of the unit and scores up the pump pretty bad. Figure to pay between $3000-4500 for a bench build and $5000+ if you have the transmission shop remove and reinstall it as well.

Thanks for the reply! Quite the expense.. cost of ownership of this Yukon has been brutal. Are there any other services/ parts I should have them do/replace while their at it?

 

[NickTransmissions]

Thanks for the reply! Quite the expense.. cost of ownership of this Yukon has been brutal. Are there any other services/ parts I should have them do/replace while their at it?

You're welcome!
Yes, have the shop install a much better/upgraded torque converter with a .050+ thick clutch. I'd also do the following:

- Sonnax Zip Kit
- Sonnax 3-5-R HP apply ring (allows for an extra friction and steel in that clutch)
- Sonnax 4-5-6 piston kit (allows for an extra friction and steel in that clutch)
- Sonnax billet 1-2-3-4 piston (won't crack like the factory piston)
- Reinforce the welds on the 3-5-R clutch drum to prevent leaks (common problem, mostly in pre-2010 units)
- Completely overhaul pump, machining both working surfaces and rotor/slide pocket so clearance is .0015 between rotor surface, slide surface relative to pump body deck surface
- Transgo unbreakable pump ring kit
- Updated GM HD parking rod assembly
- Updated GM cooler bypass valve to keep temps around 175-180 max at all times (or run a delete kit from Superior Technologies)

Check out my 6L80 Information thread for a complete list of all parts and upgrades available for these transmissions and let me know if you have any more ?s

 

[Borrowed_Time068]

You're welcome!
Yes, have the shop install a much better/upgraded torque converter with a .050+ thick clutch. I'd also do the following:

- Sonnax Zip Kit
- Sonnax 3-5-R HP apply ring (allows for an extra friction and steel in that clutch)
- Sonnax 4-5-6 piston kit (allows for an extra friction and steel in that clutch)
- Sonnax billet 1-2-3-4 piston (won't crack like the factory piston)
- Reinforce the welds on the 3-5-R clutch drum to prevent leaks (common problem, mostly in pre-2010 units)
- Completely overhaul pump, machining both working surfaces and rotor/slide pocket so clearance is .0015 between rotor surface, slide surface relative to pump body deck surface
- Transgo unbreakable pump ring kit
- Updated GM HD parking rod assembly
- Updated GM cooler bypass valve to keep temps around 175-180 max at all times (or run a delete kit from Superior Technologies)

Check out my 6L80 Information thread for a complete list of all parts and upgrades available for these transmissions and let me know if you have any more ?s

Excellent, thank you! Is there a specific brand TC you’d recommend?

 

[NickTransmissions]

Excellent, thank you! Is there a specific brand TC you’d recommend?

The shop will know what to go with but i have good luck with Circle D for high performance as well as my own local builder who does converters for 99% of all my rebuilds.

 

[Borrowed_Time068]

The shop will know what to go with but i have good luck with Circle D for high performance as well as my own local builder who does converters for 99% of all my rebuilds.

So the shop just called. I won’t have time to get over there until tomorrow for them to explain everything to me. But they are saying the torque converter is the issue, but that the entire transmission needs to be rebuilt. $5,800 or $6,025 with heavy duty TC. Ouch. Should I get another opinion? This is a reputable transmission specialist that’s been around a long time and has done work for me before. Huge expense!