2018 Suburban transmission trouble for relatives

[Chris142]

My wife's brother and his oldest daughter drove from Oregon to visit us and my wife's mother here in Southern ca. Drove a 2018 suburban with 110k miles on it.

They picked up my wife, her mom, cousin and daughter. The 6 of them piled into the Suburban and went to Disneyland near Los Angeles.

Went to leave last night and the transmission barely moves the truck.

Nothing much I can do from here being 100 miles away. Google says it doesn't have a dipstick.

They got a motel last night and tomorrow will have to find a shop to deal with it.

All I know for now.

 

[martinq]

Interested to know the service history for this vehicle especially for the transmission. Really hoping that the fluid has been changed out at least twice so far.

 

[SwampSurvivor]

It seems like 6,8,9,10 speed transmissions have been really problematic for GM. With the 6 speed, something fails inside the torque converter and ruins the rest of the transmission. I don't believe maintenance can help that one.

Miss the days of the 4L60 going 300,000 miles until the truck broke in half from rust.

 

[4wd]

My wife's brother and his oldest daughter drove from Oregon to visit us and my wife's mother here in Southern ca. Drove a 2018 suburban with 110k miles on it.

They picked up my wife, her mom, cousin and daughter. The 6 of them piled into the Suburban and went to Disneyland near Los Angeles.

Went to leave last night and the transmission barely moves the truck.

Nothing much I can do from here being 100 miles away. Google says it doesn't have a dipstick.

They got a motel last night and tomorrow will have to find a shop to deal with it.

All I know for now.

A 6L and no dipsticks? … both my 2017 & 2018 had them
My 10L does not …

 

[SeaJay]

Interested to know the service history for this vehicle especially for the transmission. Really hoping that the fluid has been changed out at least twice so far.

Wouldn't the recommended tranny fluid change on that vintage be every 60k miles or so?

 

[D60]

I bet they were getting converter shudder and just oblivious to it.

 

[Chris142]

Interested to know the service history for this vehicle especially for the transmission. Really hoping that the fluid has been changed out at least twice so far.

They have only had it a few months.

 

[Chris142]

A 6L and no dipsticks? … both my 2017 & 2018 had them
My 10L does not …

I was just going off Google. Im not familiar with this era of gm trucks

 

[jjf729]

That should have a dipstick.

Regardless of fluid condition, service history, etc., if you are buying anything with a 6L80E, you need to buy a powertrain warranty or have money in the bank for a remanufactured transmission.

Knowing about the issues with these, I got an extended powertrain warranty when I bought my 2016 Suburban two years ago. They paid for my remanufactured transmission in February.

 

[4wd]

Wouldn't the recommended tranny fluid change on that vintage be every 60k miles or so?

I put a B&M plug in mine and changed 5 quarts a year (20 minutes) - filter twice in 115k trouble free miles …

 

[Chris142]

It's currently working. I talked with them this morning and for giggles told them to remove a battery cable. Go to breakfast then put the cable back on .

After doing that it went into gear and is driving normal..... for now.

 

[4wd]

It's currently working. I talked with them this morning and for giggles told them to remove a battery cable. Go to breakfast then put the cable back on .

After doing that it went into gear and is driving normal..... for now.

Good news - now another 9 pages and most won’t see this comment

 

[clinebarger]

It's currently working. I talked with them this morning and for giggles told them to remove a battery cable. Go to breakfast then put the cable back on .

After doing that it went into gear and is driving normal..... for now.

That can be misleading, When the converter fails, It sheds a lot of debris, This debris packs into the filter & clogs it up......Letting it sit for a bit can unpack the filter just enough for the unit to operate again....Until the filter loads up.

 

[Chris142]

That can be misleading, When the converter fails, It sheds a lot of debris, This debris packs into the filter & clogs it up......Letting it sit for a bit can unpack the filter just enough for the unit to operate again....Until the filter loads up.

Thats why I said its working for now I dont have high hopes for it

 

[clinebarger]

I bet they were getting converter shudder and just oblivious to it.

The unit itself is pretty stout, Cracks in the 1234 piston & 35R drum are caused by runway line pressure.....PR Valve wear is the cause.

A good percentage of 6L80/90 unit could be saved with a Tune, Billet twin disc converter, Blueprinting the pump & a Sonnax Zip Kit at around 80,000 miles.