2012 Yukon Denali 6L80 Issues/Advice

Foggy

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Sonnax Zip Kit and parts are the best.. They fix all the original flaws.. The biggest
is in the tiny clutch inside the torque converter...
Replacing these torque converters is almost preventative maint ...
There are better aftermarket converters that have a large clutch apply area...
And don't just judge work or price on warranty....
If it's a ****** trans, it will show itself in a couple of months... IF its' a quality
build and you take care of it, it'll outlast the truck...
BTW: service your auto trans (filter and fluid) every 20-25K.. 50K is way too long,
these things are almost 6000 lbs... trannys are working hard all the time
 

Pointer 21

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I really appreciate ALL the information this forum has provided. I was going to drop off the Yukon on Tuesday but Houston had the storm come through leaving many of us without power.

Collectively it seems that everyone agrees that a rebuild with the following should be a solid transmission: Sonnax Clutches
Precision Torque Convertor
AC Delco for solenoids etc.

A post for another thread but I believe I'll be doing Cat work right after this as I've heard that bad cats hurt the transmission/motor (hoping this doesn't eat my lunch) along with the rest of the squeeks under my front end that I have yet to dive into.
 

Seapro

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Good Morning Gurus! I'm new to the board but have been using it as a resource (Great One at that).

Quick Facts:

-2012 GMC Yukon Denali 152,000K miles
-Bought Brand New
- 0 problems to date

ISSSUE: I was running fine last week, felt something a LITTLE sketchy when shifting out of first (at a stop light).
Next day was driving on the freeway (AND ZOOOMMMM) RPMS hit 3,000 + and I'm doing 30 mph until I can get to the closest town.
After I set for awhile I was able to drive with little problems; HOWEVER, the engine light came on AND has sense turned off.

My question: I've been to one mechanic who had good reviews. He didn't even look at it and just said "yeah, I know what's going on $3300 for aftermarket parts and a rebuilt transmission".
I gather he knows his stuff; however, how do I know what's actually gone in that transmission? Seems to me like a Torque Converter would be necessary and whatever else. Also, he would be using Sonnax aftermarket parts? **Opinions here?***

Is this just a "fix it once and replace everything while you're in there approach" and is it advised?

I believe I will be needing work done to my Catalytic convertor and likely some suspension repairs in the near future.

Trying to figure out my total cost of ownership or if its time to abandon ship and move onto the next problem vehicle.

Any advice is appreciated - My apologies for the long post.
Hi, just some input from my experience with a transmission problem. The transmission, according to my mechanic, is controlled by a module. I would have a shop or mechanic who kind of specializes in GM's put it on their scanners and give you a report on the issue. I believe even though your check engine light went out the system still holds it so you can see what that was all about. In my case I had the module reprogrammed and it has been running fine this year. Just something else you might want to check.
 

Pointer 21

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I'm afraid you might be onto something here....I got the vehicle back yesterday (still licking my wounds from the complete rebuild). He did put a rear main seal in for free BUT I'm still leaking oil (in the pan), need suspension work and to replace both sway bar links.

The codes I'm throwing are as follows:

B1600:Mirror Motor Vertical Circuit
B3782: Air flow Control 10
Circuit Open or Short
B0433: Temperature Control
3 Feedback Circuit Open

All of this was according to him and I have a shop looking at it this AM.


Any advice from anyone on how I should proceed?
 

wsteele

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I'm afraid you might be onto something here....I got the vehicle back yesterday (still licking my wounds from the complete rebuild). He did put a rear main seal in for free BUT I'm still leaking oil (in the pan), need suspension work and to replace both sway bar links.

The codes I'm throwing are as follows:

B1600:Mirror Motor Vertical Circuit
B3782: Air flow Control 10
Circuit Open or Short
B0433: Temperature Control
3 Feedback Circuit Open

All of this was according to him and I have a shop looking at it this AM.


Any advice from anyone on how I should proceed?
The codes above (other than th mirror) are HVAC codes and none are related to your transmission (or TCM). They are all BCM codes.
 
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Pointer 21

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I guess that's good news? My AC isn't blowing cold air on the driver side (I thought it was an actuator door).

The other shop just called and quoted me out on my rear main seal. The transmission shop replaced the rear main seal but nothing else (the gaskets etc). so I'm still leaking oil.
My transmission guy is strictly transmission and won't touch the other stuff normally, but I talked him into the rear main seal while he was in there. They're saying it ALL needs to be replaced including my suspension work.

I'm at a loss with all these repairs and can't tell whos giving me the shaft (if anyone).

Is it just as labor intensive to replace the gaskets around the oil pan as the rear main seal? In other words without him replacing the gaskets was that basically all for nothing (since I'm still leaking oil)?

BAD Week so far!!
 

wsteele

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I guess that's good news? My AC isn't blowing cold air on the driver side (I thought it was an actuator door).

The other shop just called and quoted me out on my rear main seal. The transmission shop replaced the rear main seal but nothing else (the gaskets etc). so I'm still leaking oil.
My transmission guy is strictly transmission and won't touch the other stuff normally, but I talked him into the rear main seal while he was in there. They're saying it ALL needs to be replaced including my suspension work.

I'm at a loss with all these repairs and can't tell whos giving me the shaft (if anyone).

Is it just as labor intensive to replace the gaskets around the oil pan as the rear main seal? In other words without him replacing the gaskets was that basically all for nothing (since I'm still leaking oil)?

BAD Week so far!!
There are a number of common leak points under there. The oil pan gasket is a pretty big job and likely should be left to professionals unless you are pretty handy. Check out YouTube if you want to know all most of the common leak points on your engine.

The AC stuff won't cause your transmission (or any other drivetrain) issues, so given the change of seasons coming, maybe address the oil leaks first.
 

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