Transmission Woes :-(

newdude · June 26

On 6/20/2026 at 10:12 AM, No1UKnow said:

I wonder as well, why they would send me a text message with links to these suggested procedures totalling over $10,000 without even the slightest hint of how they arrived at these being necessary.

Talk to the service manager. Have him give you a copy of the back of the repair order with the diagnostics and all and any DTCs found.

No1UKnow · June 26

I typed up my experience - what happened with my truck - and loaded it into CLAUDE AI. I've attached that dialogue here. I don't for a second think that AI is a match for experience and diagnostics, but this response is based on a lot of experience that's made its way onto the web.

What do you all think? Is this a good way to think about this problem?

Claude AI on My 2019 chevrolet colorado transmission problem.pdf

newdude · June 26

2 minutes ago, No1UKnow said:

I typed up my experience - what happened with my truck - and loaded it into CLAUDE AI. I've attached that dialogue here. I don't for a second think that AI is a match for experience and diagnostics, but this response is based on a lot of experience that's made its way onto the web.

What do you all think? Is this a good way to think about this problem?

Claude AI on My 2019 chevrolet colorado transmission problem.pdf 231.71 kB · 1 download

We (and Claude) NEED all the codes to help steer this.

If the service manager won't budge and give you a detailed diagnostics with all DTCs, we and Claude are sitting duck.

If the SM won't budge, call GM customer service and get them to provide you that info from the dealer.

Edited June 26 by newdude

No1UKnow · June 26

Also, on the BAT Auto Technical Forum, I had a fellow respond in this way, referring perhaps to a possible ground fault sutuation:

ok at my shop i have seen this problem ok i would change the fluid if this is a 8 speed use mobil 1 LV HP also and a bottle of Motorcraft XL-3 trust me it work's great on the shudder problem also a new filter now onto the can bus line issue on the driver side down by the frame you should see a big connector just below the manifold check there for a issue unplug and clean good and drive it again see what happend

Edited June 26 by No1UKnow

asilverblazer · June 27

8 hours ago, newdude said:

OP's quote is parts and labor. Not just parts.

The # you found isn't the right one. But besides that, the right # is the same price within a couple bucks. $5802.01.

Now, factor in labor and fluids. Book time is 17.1 hours for a Colorado 8 speed. At $200/hr for a dealer average rate, its $3420 just in labor. We are already at $9222. Fluid and other necessary items, there's your $400-500 more.

Also. Your "discounted" transmission. Which is 99% likely quoted off of GM Parts Direct as that's the MSRP I found on their site.

You failed to note the $597 in shipping charges. So we are right back almost to MSRP. $5794. Oh. AND, you better have the $4000 for the core charge which you'd have to pay and get refunded, AND you gotta pay to SHIP THE CORE BACK.

So now you'd have paid MORE to buy that one online yourself, just for the transmission, even after you get your core refunded.

Yep, just a quick reference point.

My main point being I’d do a thousand other things before I’d pay 10k for a transmission.

Speaking in ignorance cause I don’t look at these trucks, what is it worth? 20k?

No1UKnow · June 27

8 hours ago, asilverblazer said:

Yep, just a quick reference point.

My main point being I’d do a thousand other things before I’d pay 10k for a transmission.

Speaking in ignorance cause I don’t look at these trucks, what is it worth? 20k?

The truck had about 10,000 miles on it when I purchased it in the fall of 2020 for about $31000. KBB seems to think it's worth between $20 and $25k now, assuming a good transmission.

asilverblazer · June 29

On 6/27/2026 at 8:34 AM, No1UKnow said:

The truck had about 10,000 miles on it when I purchased it in the fall of 2020 for about $31000. KBB seems to think it's worth between $20 and $25k now, assuming a good transmission.

That's a tough spot to be in, I personally would question spending 1/2 the book value on a repair vs. selling it as-is.

Presuming you own it out right, sell it for 10k and have a down payment for a replacement truck, or spend 10k on the one you already have...

I still think there is a cheaper transmission out there via recyclers, aftermarket or rebuild. (Cheaper than 5k for the unit)

No1UKnow · 2026-07-08T13:31:37Z

On 6/29/2026 at 10:16 AM, asilverblazer said:

That's a tough spot to be in, I personally would question spending 1/2 the book value on a repair vs. selling it as-is.

Presuming you own it out right, sell it for 10k and have a down payment for a replacement truck, or spend 10k on the one you already have...

I still think there is a cheaper transmission out there via recyclers, aftermarket or rebuild. (Cheaper than 5k for the unit)

I don't think the transmission needs to be replaced, and I don't think the dealer performed any real diagnostics. I also think it's an electrical issue. I picked the truck up from the dealer and took it to transmission expert. @newdude He pulled all of the codes (see attached). He says he doesn't do electrical, so he dropped it off at someone who does. I'm waiting to hear what they have to say. I've read about wire harness rubbing/chafing with these trucks that causes electrical problems...

Colorado Codes from Precision Transmission.pdf

Edited 7 hours ago by No1UKnow
Replacing attachment with correct file

newdude · 2026-07-08T20:30:19Z

6 hours ago, No1UKnow said:

I don't think the transmission needs to be replaced, and I don't think the dealer performed any real diagnostics. I also think it's an electrical issue. I picked the truck up from the dealer and took it to transmission expert. @newdude He pulled all of the codes (see attached). He says he doesn't do electrical, so he dropped it off at someone who does. I'm waiting to hear what they have to say. I've read about wire harness rubbing/chafing with these trucks that causes electrical problems...

Colorado Codes from Precision Transmission.pdf 1.16 MB · 2 downloads

Sounds to me that its on the high speed data line. ECM, TCM, and many other modules talk on it. Wiring issue (corrosion, terminal fretting, pinched or broken wire) or a failed module or failing module (ECM, TCM, aux chassis controller).

Edited 1 hour ago by newdude

asilverblazer · 2026-07-08T21:27:48Z

7 hours ago, No1UKnow said:

I don't think the transmission needs to be replaced, and I don't think the dealer performed any real diagnostics. I also think it's an electrical issue. I picked the truck up from the dealer and took it to transmission expert. @newdude He pulled all of the codes (see attached). He says he doesn't do electrical, so he dropped it off at someone who does. I'm waiting to hear what they have to say. I've read about wire harness rubbing/chafing with these trucks that causes electrical problems...

Colorado Codes from Precision Transmission.pdf 1.16 MB · 1 download