Torque converter issues

[swathdiver]

I recently heard about how prone the torque converters are know to fail on most the full size gm suv and trucks. I’m curious to know if there is anything you can do to prolong the life of the transmission? We have 85000kms on our 2017 yukon, I’m sure we are due for a transmission oil and filter change at the very least

The biggest killer of the torque converter and transmission in the K2s (2015-2020 SUVs) with the 6L80 is the thermostat that keeps the temperature the same as the coolant.

Folks first learned to "flip the pill" and now have the option of installing a new, lower temperature transmission thermostat on the side of the unit.

 

[chartersj]

The biggest killer of the torque converter and transmission in the K2s (2015-2020 SUVs) with the 6L80 is the thermostat that keeps the temperature the same as the coolant.

Folks first learned to "flip the pill" and now have the option of installing a new, lower temperature transmission thermostat on the side of the unit.

I'm going to do this. Instead of modifying the original I'm going to get the updated one with the lower temperature thermostat as I live in Canada.

 

[NiamLeeSin]

I've decided to do this myself. I want to see how much filings is in the pan and I want the filter changed. I will use my vacuum pump through the dip stick tube to remove most of the fluid before dropping the pan. I'm thinking I could just use the pump in between filter changes to do a half oil change

@chartersj did you find a way to diy? What kind of vacuum pump? Amy pointers or resources before I attempt this? Thanks!

 

[NickTransmissions]

@chartersj did you find a way to diy? What kind of vacuum pump? Amy pointers or resources before I attempt this? Thanks!

Any home depot or harbor freight hand-operated or powered fluid pump will work, just stick the suction end in the level check location or dipstick tube location. Or simply drop the pan (18 10mm bolts) but this can be messy so have a big, wide catch container. Check fluid color, smell and for particulate matter.

Once you have the pan off and cleaned up, drill a hole in it and weld a nut on the inside of the pan. Then use a bolt with some RTV to make a drain plug.

Cut the filter open to see if there's anything concerning such as metal particles, etc trapped in it.

For those with very early 6L80s, it's recommended to replace the IMS at this time as well since its accessible and comes off with two bolts removed.

You can swap the cooler bypass housing for GM's updated one or flip the pill and reinstall yours (just be careful with the o-rings that will likely remain on the cooler lines after you pull the housing off).

Its a fairly easy job and less messy if you use a pump to remove fluid first.

ETA: Fill and level check procedure

Its astounding to me that GM hasnt put drain plugs on all transmission pans.

 

[chartersj]

@chartersj did you find a way to diy? What kind of vacuum pump? Amy pointers or resources before I attempt this? Thanks!

As mentioned I used a siphon pump and got as much as I could through the dip stick tube. I couldn’t get the pan out from by the exhaust even after pulling it down with a ratchet strap,,, not sure why because I see lots of people that could. It was still enough to pull the filter and magnet out to clean

 

[arkie]

What transmission do you have (6 or 8 speed)?

Fluid and filter every 24-36k for daily drivers; 12-18k for heavy duty, towing, working beyond the scope of private party ownership patterns.

Failing to change the filters in these six and/or eight speed units can result in increased contamination, them getting partially restricted resulting in inconsistent oil pickup and slippage at WOT.

The six speeds (6L45, 50, 80, 90) are also prone to pump wear on the working surfaces as well as wear in the pressure regulator valve. Keeping up with fluid changes mitigates the associated risks and helps prolong the life of these units.

The eight speeds (8L45/90) have a TSB for TC shudder and harsh 1-2 upshift, primarily due to use of wrong fluid used. Per the link, flushing the trans with mobile 1 synthetic (or presumably any quality full synthetic fluid) helps.

The solenoids (or techm) in between types of transmissions are also very sensitive to contamination, moreso than earlier units like the 4L60e.

Address pattern failures by installing updated parts and performing requisite procedures on overhaul.

I have a 17 Sierra 39700 miles with the 8 speed, seems to have the torque converter shudder.
Can you recommend a good shop in the St Louis area?

 

[NickTransmissions]

I have a 17 Sierra 39700 miles with the 8 speed, seems to have the torque converter shudder.
Can you recommend a good shop in the St Louis area?

Hi @arkie , apologies but I'm not aware of anyone in the St Louis area but you can check with ATRA or perhaps search/post in the local sub-forms that cover the mid-west / Missouri, etc for a referral...General rule of thumb when shopping around is to see if the shop is willing to spend time with you, answering your questions and is able to demonstrate sufficient familiarity with your transmission type...I get calls frequently about foreign transmissions that I don't work on and the first thing I'll tell them is that I don't work them and refer them to one of my builder/shop friends who do.

Also, try to obtain exactly what parts go into the transmission, what they do in terms of any reconditioning or corrective update work (i.e. provide a better/more reliable converter than stock). If a shop isn't willing to have that kind of conversation w/you, I'd keep looking...

 

[Tahoe14]

Have you had the fluid changed to the one GM recommends for this issue with the 8speed