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

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Just Fishing

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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.
 

Just Fishing

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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.
 

j91z28d1

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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.


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
 

dmhscorpio

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

Moosemoon

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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....
2001 Yukon XL 2500 - got 276,000+ before having it rebuilt - was just starting to go. It’s great now! The rest of it is an adventure at the moment.
 

GBF1

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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....
I had to replace the torque converter at 181,000 miles. No other mechanical issues except for occasional low oil pressure.
 

bobsburban

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6L80 in a 2011 Suburban. Purchased truck at 231,000 miles, only records I got with the truck indicate second owner flushed it at 131,600 miles as part of a $3k full service which included new engine mounts (ouch...). I've got 272,000 on the truck now, which includes over 15,000 miles towing a travel trailer. I do have a 40k Tru-Cool installed.

edit to add: forgot to mention that I did a full service on the transmission when I bought the truck in July 2020 - flush, filter, pan dropped, etc... I plan on doing another at 275,000-ish, depending on mileage before our next big trip. I'll follow the 50,000 mile heavy duty maintenance recommendation after that.
 
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waveryd

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1996 Suburban K1500 4L60E with towing package, I.e. trans cooler. Rebuild at 260,000 after losing 2-4-R. Did an electronic update at that time. Lost 2-4-R at 330,000 which was repaired under warranty. Lost 2-4-R again at 570,000. Rebuild again and back on the road with over 600,000 and running good. Had fluid/filter changes at 75-100k miles with infrequent light (2000 lbs.) to moderate (6000 lbs.) towing.
 

Sagmanovich183

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I did a proactive rebuild on my 09 6l80 at about 180k.
I didn't see much wrong with it, clutches had plenty of life, bushings were fine.
only issue I found was in the 2-4 clutch pack.
It had a broken wave plate.
No symptoms at all, I don't think it would have affected it long term.

biggest thing to watch out for is the converter.
These are known to burn clutches due to the amount of slippage that's allowed.
Most recommend to replace the converter as a proactive measure since it will take out the transmisison/pump when it goes.


And my original converter was fine, I tore it apart and I found plenty of clutch material left.
View attachment 396204

They seem pretty stout IMO.
I have a 2008 6l80 in my sierra that did 220K before 2-3 flair became bad enough to have to pull over, turn off truck and restart to get it to shift again. I dropped valve body and replaced films (2 of 4 were torn) but didn't split and replace check balls. Still has flair when warmed up. Seems these had tsb stating a clutch seal redesign took place between 08-09 and potential pump issues. Loved the truck but it's in semi retirement rn.

I'm not much of a tranny guy like you so I bought a 09 yukon with 75k miles and need to figure out what to do with the 08 Sierra - probs sell for parts - idk...
 

jabre

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2007 Tahoe. Lasted 15 years and 160k miles and was operating perfectly. That is until the radiator cracked while the wife was about 100 miles from home. Told me it started driving funny when she got home. Never knew until then that the standard service should include replacing the radiator at some point. Replaced transmission with a remanufactured Street Smart transmission. Drives better than new now.
 

89Suburban

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2007 Tahoe. Lasted 15 years and 160k miles and was operating perfectly. That is until the radiator cracked while the wife was about 100 miles from home. Told me it started driving funny when she got home. Never knew until then that the standard service should include replacing the radiator at some point. Replaced transmission with a remanufactured Street Smart transmission. Drives better than new now.

I just ordered a radiator for mine. For all I know it could be original. Driver's side tank is weeping. Nipping that in the bud asap.
 

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