Time to start saving up for rebuild or new transmission?

[NickTransmissions]

Hi, I'm new to this forum. I have a 2016 Chevy Tahoe with 83,000 miles. At the end of April, I noticed that my truck would stutter/shudder/vibrate at certain speeds while accelerating, but it never set a code. I initially thought it was bad fuel, so I took the truck to my dealership where I purchased the truck in 2019 as a certified pre-owned vehicle. I was told that it was an “engine misfire” with a code of P0300 and that I needed a throttle bottle service, fuel injection service, and a fuel quality/methanol check. I was told that if I did not get the repair done, “it will continue to run the way it is and can affect the motor.” The bill for this repair would be $762 plus tax. Thankfully, I decided to get a second opinion. I took my Tahoe to a local auto repair shop and what they found was quite a shock to me. They told me that my torque converter was faulty and that it needed to be replaced. They told me that this was a “common issue” found in GM vehicles ranging from 2015-2019 and that there is a Technical Service Bulletin on it as well as some class-action lawsuits. After doing some research on the internet, I found countless truck forums with GM owners complaining of this issue on trucks with 110,000 or less just like mine.
The auto shop recommended I take the truck to a transmission shop - the guy there totally rebuilt my trans to eliminate all the GM "weak links" and put in a stronger torque converter. Problem solved! Set me back $5,000!! I couldn't believe what my dealership was trying to sell me. I am so disappointed in them. The mechanics who figured out the issue told me my truck is in great shape otherwise and I should be good from here on out.

Good call - glad you found a competent shop...A shop/builder who knows these units can build a much better unit w/all the required updates for less than a reman unit in most cases.

Those converters are junk as they come from the factory but a rebuild w/a .050-.070 converter clutch and stronger stator/owc makes a world of difference. That and a lower thermostat for the trans or deleting it all together.

 

[iboughtatahoe23]

Thanks - the TB is a good a place as any as it may be dirty and/or in need of service.

What you need is a scanner with live data feeds that can stream the data as you're driving. If your scan tool is capable of that, stick it on the vehicle then drive it around as see what it displays. Also thorougly check around the acc pedal for any mechanical issues, broken parts etc.

I have live data available. What banks can I look at ? Can also graph data.

 

[iboughtatahoe23]

Thanks nick.

 

[NickTransmissions]

I have live data available. What banks can I look at ? Can also graph data.

@swathdiver and others can answer this question more thorougly than I can but you want to compare the tps % to reality using the scanner. There are other parameters as well but admittedly, I'm not an expert at diagnosing non-trans specific issues as i only do bench builds (i never actually see the vehicles themselves).

 

[iboughtatahoe23]

@swathdiver and others can answer this question more thorougly than I can but you want to compare the tps % to reality using the scanner. There are other parameters as well but admittedly, I'm not an expert at diagnosing non-trans specific issues as i only do bench builds (i never actually see the vehicles themselves).

I see, right here I got 17% To 17.6 % steady at idle. Not sure what to compare that to.

 

[iboughtatahoe23]

Apparently 5-20% range for the tps is normal. But certain factors come into play. Is it worth looking at the throttle body with 166k?

 

[iboughtatahoe23]

Thanks - the TB is a good a place as any as it may be dirty and/or in need of service.

What you need is a scanner with live data feeds that can stream the data as you're driving. If your scan tool is capable of that, stick it on the vehicle then drive it around as see what it displays. Also thorougly check around the acc pedal for any mechanical issues, broken parts etc.

Other things to check? Before moving to step 2. I changed idler pulley, serpentine belt and cleaned maf sensor so far.


Edit: trying to fix rough idle as wel as the transmission issues I’m having.

Kinda taking it all on at once.

 

[NickTransmissions]

Other things to check? Before moving to step 2. I changed idler pulley, serpentine belt and cleaned maf sensor so far.


Edit: trying to fix rough idle as wel as the transmission issues I’m having.

Kinda taking it all on at once.

Resolve all non-transmission issues first, in whichever order you want to tackle them in. Engine itself has to be running right, gas pedal normal, TB/MAF/O2s/etc should all look and function normal.

Once you have resolved your engine and gas pedal symptoms then you can move onto the trans. This way, if it's shifting odd, slipping, clunking, shuddering, banging or flairing you know its the trans and not something else.

Bottom line - if you're slipping as mentioned in one of your previous posts [you havent yet told me when you have observed it slipping or what gear(s)] the transmission is on it's way out and will need an overhaul.

Keep us posted; perhaps others will chime in on your rough idle and gas pedal problems.

 

[swathdiver]

I see, right here I got 17% To 17.6 % steady at idle. Not sure what to compare that to.

That's really high. Has the throttle body been off and cleaned recently? If so, it may take a few drive cycles for it to adjust. BlackBear if memory serves, didn't like more than 10% and mine has historically been around 7%. Most are around 3% and that's what BB was looking for.

The dirtier the throttle plate coking, the more it will open to compensate over the life of the vehicle.

 

[iboughtatahoe23]

“Based off your post history, you have a 2014 Tahoe, a tech 2 is not compatible with anything 2014+, they use an MDI and GDS software. Most code reader can read transmission codes I have a $40 reader from Napa that works just fine for reading trans codes.”

-a Redditor from r/askmechanics