Best option for my transmission?

[NickTransmissions]

I have a scanner. No codes.

Then stop worrying about it. You have all the answers, you certainly don't need our help.

 

[petethepug]

I know you’re nerves are shot worrying about a possible major expense crunch. It’s a good thing your scanner shows no codes.

* Is the scanner Tech2 GM based?
* My 6L80 trans codes showed only when active and disappeared even with a Tech2

I have to drive with it plugged in until it triggered on the fly. TEAM UP with a pro and let them share their knowledge base with you. I won’t post any proverbs to say it subtly.

 

[NickTransmissions]

* Is the scanner Tech2 GM based?
* My 6L80 trans codes showed only when active and disappeared even with a Tech2

I see this stuff all the time - this trans will throw codes for the tehcm when the fault is in the valve body or case but the code itself points to the tehcm. I also see pressure switch intermittent faults where harsh upshifting and downshifting has been the complaint but no codes are stored. Those are just two examples, there's plenty more.

Some people love to think that the presece or absence of a code is the sole consideration when making a diagnosis and the looks on their faces are priceless when they realize how wrong they are about that.

Unless he's either imagined his symptoms or made them all up, he has a transmission problem. Whether he wants to deal with it properly (taking it to a shop or dealer with a reputable service dept) who will perform a proper diag workup or not is another matter.

 

[petethepug]

Fear (false evidence appearing real) of a huge financial event driving indecision as a survival tool until an absolutely safe opportunity arrives. Going to an Indi is the first and most frightening step to facing the facts. Getting a 2nd opinion is even harder. If you’re done all this before it’s no big deal because you know what’s on the other side of the predicament, just decisions, hopefully based on diagnosis.

My trans blew @170k just as the IRS sent me my refund check I was planning to use to pay off some bills. I would of been at a credit union borrowing the $5k+ to replace it if it was for just dumb luck.

 

[NickTransmissions]

just decisions, hopefully based on diagnosis.

Just this. Everything else is irrelevant.

No sense in prolonging the uncertainty.

Otherwise, there's literally nothing to discuss because there's no problem (e.g. his drivability symptoms are all in his head, as he has been advancing on here as of late).

Luckily you got your tax refund just at the right time. That almost never happens when it comes to vehicles and their tendancy to crap the bed on people at the worst possible time.

 

[iboughtatahoe23]

I know you’re nerves are shot worrying about a possible major expense crunch. It’s a good thing your scanner shows no codes.

* Is the scanner Tech2 GM based?
* My 6L80 trans codes showed only when active and disappeared even with a Tech2

I have to drive with it plugged in until it triggered on the fly. TEAM UP with a pro and let them share their knowledge base with you. I won’t post any proverbs to say it subtly.

Not a tech 2. Can’t afford that. And I used a Zurich z8s

I got a code for a rear propshaft speed sensor and it went away and wasn’t a stored code.

 

[iboughtatahoe23]

The code for the sensor came from one of those Bluetooth sensors the cheap ones with the app. So idk how accurate that is. My Zurich i feel is pretty reliable. Shows codes on other cars for transmission issues. And it says it’s made for GM

 

[petethepug]

Let us know what the guy at the trannie shop tells ya.

 

[SpyShops212]

There is no warranty it is as is. I grew up with Chevy and bet my life on them, not anymore haha. This thing has a clean Carfax with service records every 5000 miles 165K for a transmission to go out, it’s just too soon!

But I just found a tow brake in here under my backseat, which makes me think it was for towing damn it!

When the GM dealer replaces the transmission you get 3 year / 100k warranty.

 

[iboughtatahoe23]

@iboughtatahoe23: Check out this thread if you haven't already: https://www.tahoeyukonforum.com/threads/gm-6l80-transmission-information-thread.141927/

Also wanted to add nick;

My transmission has been shifting great lately. So wondering now why the issues seem to come and go. And worsen with cold weather. I’m leaning towards some sort of TSB vs a real critical issue.

 

[NickTransmissions]

Also wanted to add nick;

My transmission has been shifting great lately. So wondering now why the issues seem to come and go. And worsen with cold weather. I’m leaning towards some sort of TSB vs a real critical issue.

Do you know what a TSB is and it's purpose?

ETA: When was the last time you gave that thing a service (fluid, filter)?

 

[iboughtatahoe23]

Do you know what a TSB is and it's purpose?

ETA: When was the last time you gave that thing a service (fluid, filter)?

A technical service bulletin, in short (to me) is a known issue that usually has a solution or fix. Examples: fluid leaking through the connector on the transmission harness, a loose transmission wire harness or something like that. Like a defect from the factory.

What if I have one of the transmission TSBs?

And yes: fluid I know for sure was changed. Can’t comment on the filter. But I am guessing it was changed if the dealership changed the fluid.

 

[NickTransmissions]

A technical service bulletin, in short (to me) is a known issue that usually has a solution or fix. Examples: fluid leaking through the connector on the transmission harness, a loose transmission wire harness or something like that. Like a defect from the factory.

What if I have one of the transmission TSBs?

And yes: fluid I know for sure was changed. Can’t comment on the filter. But I am guessing it was changed if the dealership changed the fluid.

A TSB is a technical service bulletin that is published by the manufacturer for consumption by the general public and service techs to advise of a design flaw or oprational defect of a system, subsystem or component that is common to a large product segment or sub-segment of vehicles in a given prod date range that may result in adverse drivability experiences stemming from associated mechanical issues/failures for operators of impacted vehicles.

The consequences for vehicle operators will depend on the severity of the issue.

Example 6L80 TSB: 3-5-R drum leaks due to insufficient/inadequate welds at the base. Burns up 3-5R clutch pack. Results in loss of Reverse, third and fifth gear.

This is a (very well) known issue, to use your verbiage, that requires removal and disassembly of the transmission to fix!

If you think TSBs only apply to "minor" issues that require little expense/LOE to remediate, you're sadly mistaken. Though in your case, none of your issues should be considered minor at this point since you dont actually work on your Tahoe (yet). So far, you have just started threads to "talk" about things as you notice them - some are more concerning than others, if looking at it from your point of view.
Problems dont fix themselves, they just get worse the more time passes.

To answer your question, "what if I have one of those TSBs?"

Response: It depends what it is. Hopefully your transmission issues don't worsen. I was thinking your filter was partially clogged (and it could still be) but not nearly as likely as it was changed recently. Otherwise it amost sounds like you have a converter drain back problem, which is not common to these transmissions. Lastly, TEHCM (intermittent pressure switch failure in either TFP 3 or 4) which requires you to replace the TEHCM. Can also be either your 2-6 regulator valve and/or 1-2-3-4 regulator valve sticking when cold. Possibly the compensator feed reg valve as well...Whichever the case may be, you will need to overhaul or replace the valve body to fix.

Have you bought the manual yet?

Also, let us know what's up with your flexplate. I sincerely hope for your sake that it's not cracked. If it is, that transmission must come out IMMEDIATELY, if not sooner, or you risk catastrophic engine and transmission damage. Not only that, its completely unsafe to drive it cracked as is. If it breaks completely while you're driving, it may stall out the vehicle, which means total loss of power and potentially control (think major accident).

Telling you this now so that, in the event you realize it's cracked, you dont assume its fine to keep driving which up to this point has been your default response to issues as they arise.

 

[iboughtatahoe23]

I was wondering why shift flares happen? I was going through my old threads and it seems most of the issues have subsided for now with the transmission. I still get a shift flare in 2-3 gear sometimes if I really put down the pedal (like when I need to get on the free way, or turn into traffic)

And sometimes it will rev a little past 2k sometimes if it’s under 90°F it seems like

@NickTransmissions


Can’t complain I guess. It’s lasted me so far

 

[NickTransmissions]

I was wondering why shift flares happen? I was going through my old threads and it seems most of the issues have subsided for now with the transmission. I still get a shift flare in 2-3 gear sometimes if I really put down the pedal (like when I need to get on the free way, or turn into traffic)

And sometimes it will rev a little past 2k sometimes if it’s under 90°F it seems like

@NickTransmissions


Can’t complain I guess. It’s lasted me so far

3-5-R clutch pack wear caused by leaking welds at the base of the 3-5-R drum is what's causing your 2-3 flare. A flare shift is by definition, a temporary/fleeting neutral condition that happens becuase one applied element is coming off before the next applied element in the shift sequence is able to fully apply. In this case, your 2-6 clutch is releasing and your 3-5-R clutch is taking too long to fully come on, generating the flare. The excessive shift time is due to the loss of friction material, creating additional clearance in that pack that shouldn't be there.

It will get progressively worse over time until one day you will begin to slip in 3rd (followed by slippage in 5th and reverse). Sucks but there's no way to fix or stop it short of rebuilding the unit and reinforcing the base welds on the drum.

 

[iboughtatahoe23]

3-5-R clutch pack wear caused by leaking welds at the base of the 3-5-R drum is what's causing your 2-3 flare. A flare shift is by definition, a temporary/fleeting neutral condition that happens becuase one applied element is coming off before the next applied element in the shift sequence is able to fully apply. In this case, your 2-6 clutch is releasing and your 3-5-R clutch is taking too long to fully come on, generating the flare. The excessive shift time is due to the loss of friction material, creating additional clearance in that pack that shouldn't be there.

It will get progressively worse over time until one day you will begin to slip in 3rd (followed by slippage in 5th and reverse). Sucks but there's no way to fix or stop it short of rebuilding the unit and reinforcing the base welds on the drum.

Yea it seems to shift, but rev a hair higher, after it’s shifted. It’s strange. in 2-3, and only when I floor it appears.

I’m at 170k, for it lasting this long and still kicking I’d say that’s pretty good for a Chevy transmission. I’m gonna run y till it’s not driveable. I got a really good, and new job so I’ll have money put aside for a potential rebuild or a new unit.

 

[NickTransmissions]

Yea it seems to shift, but rev a hair higher, after it’s shifted. It’s strange. in 2-3, and only when I floor it appears.

I’m at 170k, for it lasting this long and still kicking I’d say that’s pretty good for a Chevy transmission. I’m gonna run y till it’s not driveable. I got a really good, and new job so I’ll have money put aside for a potential rebuild or a new unit.

Not strange at all-simply the beginning of the end of that unit's life...Have it rebuilt locally by someone who knows those transmissions when the time
comes. Most remans leave alot to be desired.

 

[donjetman]

I was wondering why shift flares happen? I was going through my old threads and it seems most of the issues have subsided for now with the transmission. I still get a shift flare in 2-3 gear sometimes if I really put down the pedal (like when I need to get on the free way, or turn into traffic)

And sometimes it will rev a little past 2k sometimes if it’s under 90°F it seems like

@NickTransmissions


Can’t complain I guess. It’s lasted me so far

our 6L80 has had the 2-3 flare above 3k rpm when cold since we bought it 5 yrs and 60 k miles ago. So I lift off the gas pedal during the 2-3 shift a little under that condition. I do used atf analysis and change the Dexron6 each 25k miles and filter each 50k miles.
It is driven conservatively and mostly hwy, no towing.

 

[Geotrash]

our 6L80 has had the 2-3 flare above 3k rpm when cold since we bought it 5 yrs and 60 k miles ago. So I lift off the gas pedal a little under that condition. I do used atf analysis and change the Dexron6 each 25k miles and filter each 50k miles.
It is driven conservatively and mostly hwy, no towing.

My '07 does it sometimes too, and my '12 will do it under full throttle when towing only, but also not all the time. Full throttle launches when towing are rare but sometimes necessary like when I realize at the last minute that I need to get over a lane coming out of a light.

 

[iboughtatahoe23]

Good to know I’m not alone, other than that she drives like a dream