How many miles did you get out of your original Transmission?

For the op, he has a 09 so it's the 6l80.

Only failures i have read/heard about all come from the converter clutch failing, then it sends metal into the transmission pump.

For my tahoe, i believe the transmission fluid was original.

It did great considering... lol

They do make service kits to prevent failure and to help a worn valve body.

Another known failure point that can be caught early would be the pressure switches inside the TECHM.



Non technical peeps can ignore this part, down into the weeds i go!!

my shift kit that came with the "repair" parts also came with rebuild parts and seals for the TECHM, i bought a tool make by sonnax to help with seal installation, that came with spare laminates.

I did that as a proactive measure on my 6l80 when i first bought it.

Later i had some other issues unrelated to the transmission, but it still lead me to look at the transmission as suspect.

That lead me into an investigative rebuild of my 6l80, and it got all of the upgrades that i thought would apply to my future use of the tahoe, and to help prevent issues with the engine upgrade.

There is a company called sonnax that makes transmission parts for the rebuilder.
They specialize with upgrades and addressing known failures and issues.

Tons of documentation on their website.
Addressing all sorts of symptoms, their possible cause, and their solution using their products.

Transgo is also a good source, but they don't like shadetree mechanics, their documentation is not freely shared.
But they still make fantastic products.


Anyways, the 6l80 is a fantastic transmission imo.
It was an absolute pleasure to work on.

The only other transmission that i have worked on was the 700r4(4l60) in my vette.
That was the first rebuild i ever did.

The other was mostly just valve body work on my s10, with the 4l60e.

That's really where i cut my teeth, and it gave me the confidence to attempt the rebuild on my vette.

For the 4l60e on our tahoes, they should have all of the important updates.

For the 700r4 in my vette, most of the upgrades from the later 4l60s were a drop in upgrade for that old 700r4.

I did forget about one known failure on the 6l80, early units suffered from piston failure, and drum cracking in the 1-2-3-4 5-6 drum.

Clutch burning etc.
Easy miss for rebuilders, so it's called out in lots of documentation.

The earlier units also had an issue with the pump stator design, that just lead to some shifting flare and delay.

Your 09 shouldn't be affected.


Biggest complaint i had rebuilding the 6l80 was the cost of parts.
Much of that could have been supply issues, but i couldn't source many of the parts from the local parts suppliers.

Ebay and amazon were my best friend.

214K on my 2011 6l80, when I rebuilt it preemptively. Nothing was wrong and very minor wear on the 3-4-5 frictions, so realistically could have gone another 100K with just a new converter.

czargee said:

Owner of a 2004 GMC Yukon SLT. Bought the Yuk in 2005 with 36K and now has over 312K.

Original tranny and shamefully only changed the tran fluid once when I got it. Fortunately old faithful is still running smooth as the day I bought it. Go figure.

I heard after you passed a certain number of miles without changing the tran fluid, you just leave it.

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I've. heard that a lot and no clue if it's real on not. but yours would be very interesting to send off a fluid sample for testing, but you'd have to suck some out of the dip stick tube. that's a pretty amazing amount of miles on the fluid

2001 Yukon XL SLE 4x4. It has original engine and transmission. 421,000. I am the original owner. Not sure if this is unusual or the norm.

421k... epic.

right around 198,000 miles on my 2007 before a rebuild. The 2-4 band went on mine, not sure the state of the clutches though. They could've still been good had it not been for that band.

2004 Yukon XL Denali. 6.0L
Tranny went at 185k.
No idea about previous maintenance. Came with aftermarket trailer brake, so someone was doing a bit of towing at one point.

2007 Yukon Denali - 255,000 mi. Swapped Trans Fluid every 50,000 - 75,000 miles.

soonrfish said:

2009 suburban- went out at 125k. I purchases with 122k, fluid looked good, but no way of knowing maintenance history. Just curious what those of you got out of the original tranny, especially if you are an original owner. My in laws sold their 1 owner with 230k and original tranny.

Just wondering if the Chevy 100k miles stigma is real....

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I only got 285 K out of my 1999 Tahoe 2 door.