2020 3.0 10 Speed Noise/Issues

acmech87 · May 1

I've had a slow coolant leak for awhile but couldn't locate the source of it until now. The aux water pump finally went bad. I had been keeping it on life support by monitoring the coolant levels and refilling as needed. After it finally went bad is when the transmission started making the god awful noise you hear in the Video.

As soon as it started chattering I got off the road ASAP. The truck never went into limp mode, threw any codes, or had issues shifting. The noise was bit quieter when in reverse.

I've identified the noise to be coming from the transmission. Looking for assistance in what the issue could be before I start dismantling.

Edited May 1 by acmech87

newdude · May 1

30 minutes ago, acmech87 said:

I've had a slow coolant leak for awhile but couldn't locate the source of it until now. The aux water pump finally went bad. I had been keeping it on life support by monitoring the coolant levels and refilling as needed. After it finally went bad is when the transmission started making the god awful noise you hear in the video. (Link at the end of post)

As soon as it started chattering I got off the road ASAP. The truck never went into limp mode, threw any codes, or had issues shifting. The noise was bit quieter when in reverse.

I've identified the noise to be coming from the transmission. Looking for assistance in what the issue could be before I start dismantling.

Video

Did you ever get any transmission overheat warnings? What was the temp?

I'm 99% sure you've got 2 separate issues going on.

The primary auxiliary coolant pump (left front of truck) handles the charge air cooler and the fuel cooler. That's it. Has its own small reservoir too. It is not tied to the transmission or engine oil coolers.

The main cooling system is responsible for coolant flow to the engine, radiator, heater core, transmission and engine oil cooler. The transmission also has its own aux cooler mounted at the front of the truck. The coolant flow control valve dictates targeted cooling demand as needed.

As for the transmission issue, I'm gonna take a guess that its the pump gear. Read here - 22-NA-232 1..3 (nhtsa.gov)

Edited May 1 by newdude

acmech87 · May 1

9 minutes ago, newdude said:

Did you ever get any transmission overheat warnings? What was the temp?

I'm 99% sure you've got 2 separate issues going on.

The primary auxiliary coolant pump (left front of truck) handles the charge air cooler and the fuel cooler. That's it. Has its own small reservoir too. It is not tied to the transmission or engine oil coolers.

The main cooling system is responsible for coolant flow to the engine, radiator, heater core, transmission and engine oil cooler. The transmission also has its own aux cooler mounted at the front of the truck. The coolant flow control valve dictates targeted cooling demand as needed.

As for the transmission issue, I'm gonna take a guess that its the pump gear. Read here - 22-NA-232 1..3 (nhtsa.gov)

No overheat warnings at all. I wasn't religious in monitoring the trans temp but when I did it never went over 200. 202 may 205 was the highest probably.

As for the aux water pump, that had been leaking over time and its being replaced now.

I'm mistaken then, I thought it had a part in helping cool the transmission.

=============

I just read over that service bulletin and I am now confident that is my issue.

With this issue being on a SB, are they treated like recalls or is the cost of repair still on the customer?

Edited May 1 by acmech87

acmech87 · May 1

22 minutes ago, newdude said:

As for the transmission issue, I'm gonna take a guess that its the pump gear. Read here - 22-NA-232 1..3 (nhtsa.gov)

I just pulled my build sheet and it turns out I have the 8 speed not the 10 speed. Is this SB still applicable?

newdude · May 1

13 minutes ago, acmech87 said:

I just pulled my build sheet and it turns out I have the 8 speed not the 10 speed. Is this SB still applicable?

If you have the 3.0 Duramax you have the 10 speed. 8 speed has never been paired to the 3.0 Duramax.

RPO code MQB is for the 10L80.

acmech87 · May 1

3 minutes ago, newdude said:

If you have the 3.0 Duramax you have the 10 speed. 8 speed has never been paired to the 3.0 Duramax.

RPO code MQB is for the 10L80.

Awesome, thank you!

I just did a basic build sheet search online...

newdude · May 1

1 hour ago, acmech87 said:

Awesome, thank you!

I just did a basic build sheet search online...

QR Code on Certification Label Offers More RPO Codes – TechLink (gm-techlink.com)

acmech87 · May 2

8 hours ago, newdude said:

Did you ever get any transmission overheat warnings? What was the temp?

I'm 99% sure you've got 2 separate issues going on.

The primary auxiliary coolant pump (left front of truck) handles the charge air cooler and the fuel cooler. That's it. Has its own small reservoir too. It is not tied to the transmission or engine oil coolers.

The main cooling system is responsible for coolant flow to the engine, radiator, heater core, transmission and engine oil cooler. The transmission also has its own aux cooler mounted at the front of the truck. The coolant flow control valve dictates targeted cooling demand as needed.

As for the transmission issue, I'm gonna take a guess that its the pump gear. Read here - 22-NA-232 1..3 (nhtsa.gov)

As I was trying to look up the differences between the old design and new design I found this...

The most common problem with the oil pump drive gears of the FORD 10R80 transmission and the similarly designed GM 10L90 transmission is transmission noise from the torque converter. But according to the assurances of the manufacturers themselves, the noise is associated with the design of the gear teeth, namely the rectilinear arrangement of the teeth. This tooth design is less durable compared to helical gears, since the contact patch in gears with a linear arrangement of teeth is smaller, which in turn affects strength.

There are cases when the teeth on the drive gear are damaged, which ultimately entails the complete destruction of the gear. This problem is more common on transmissions installed on vehicles with diesel engines than on gasoline versions.

After working on the mistakes, the manufacturer changed the type of gear from linear to helical.
Helical tooth gears have a larger contact patch, which allows them to withstand greater loads with fewer teeth.
This design is more reliable than linear gears.