Transmission temperature 10speed with 3.0 LZO Duramax

[steve king]

While driving today I noticed my transmission temperature was between 196-200 degrees.  Engine RPM 1300. Ambient temp was 50-65 F.  Driving speed mostly 55 mph on fairly level terrain.  Not towing.  The trans temp seems high to me. I thought it would be 170-180F with those conditions. 
What trans temp are others seeing with the same drivetrain?

[Z45]

Completely stock?

 

160-200 is normal operating range.   How much the trans is shifting will increase the temps.

[Pairofkings]

Yes it’s totally stock. Had truck for two weeks, less than 500 miles.  Operating in normal range with trans in drive and 2 wheel drive on transfer case.  I did not notice excessive shifting.  I would not expect to see 200F unless I was towing in high ambient temperatures.  Thanks for your response. 

[CamGTP]

That's pretty normal in my opinion. They try to run a warmer temp to reduce drag for that .1 mpg increase because it all matters with CAFE.

 

They offer a lower temp transmission thermostat on the 6 speed and I think 8 speeds now too, GM made it because of high failure rates to those transmissions. Not sure what the 10 speed uses.

[redwngr]

That's higher than mine ( a '21 LM2 ) runs for 55 - 60ish mph, steady speed on level ground with no wind and no trailer. 

(Perhaps unless it has just come from a period of stop/start in town type driving.)  

 

Takes 10 or 15 miles of 2 lane at those speeds for mine to warm and stabilize, but when it does it will be in the 175 -185 range. 

Only time I've seen 195 - 200 range was on a very hot day, after 4 or so hours of towing and then stuck in stop and go for 30 or 40 minutes due to an accident ahead.

 

Perhaps the LZO trans cooling set-up is different.

[newdude]

Thermal Bypass full opens at 158F.  Transmission fluid check temperature range is 161-176F.  

[redwngr]

If 'full open' is 158, is 'starts to open' also spec'd?

 

[mjonesjr84]

I have the PPE thermal delete block and PPE transmission cooler on my '22 3.0 LM2. My temps under the same conditions as the OP is usually between 140-160*F. I was seeing the same temps as the OP before I installed the PPE parts. 

 

Thermal Bypass Valve:

https://ppepower.com/products/transmission-fluid-thermal-bypass-valve-gm-3-0l-duramax-10l80?rq=yr_2022~mk_chevrolet~md_silverado-1500~ai_6-cyl-3-0-liter-turbocharger&variant=42081986183411

 

Transmission Cooler:

https://ppepower.com/products/cooler-transmission-fluid-2020-gm-3-0l-1500-bar-and-plate?rq=yr_2022~mk_chevrolet~md_silverado-1500~ai_6-cyl-3-0-liter-turbocharger&variant=42081985265907

 

This is the comparison of the stock transmission cooler and the PPE.

Edited April 11, 2023 by mjonesjr84

[Pairofkings]

Thank you for the great information.  It appears pretty straightforward to change the bypass valve.  How difficult was it to add fluid to the transmission?  

[mjonesjr84]

1 hour ago, Pairofkings said:

Thank you for the great information.  It appears pretty straightforward to change the bypass valve.  How difficult was it to add fluid to the transmission?  

 

The hardest part was getting the plug out. The video below shows how to add fluid after he installs the PPE transmission pan. It took me just shy of a quart changing the block and transmission cooler. 

 

FYI, if you do the cooler, get yourself a pair of the fittings from the dealer. I was lucky and didn't lose any of my clips, but could see where it would be very easy.

 

 

[superdashdad]

That is the exact temperature my '23 runs at.  I'm thinking of installing the bypass block to lower the temps.

[Gangly]

Those temps are fine/normal.  Mine runs at 185 all day long, but will kick up to the 190's under load(elevation changes) or stop and go traffic.  I have a TBV sitting on the work bench ready to go in, but I simply haven't had the time to do it and the current transmission temps are adequate for right now.

[SFLTruck]

On 4/9/2023 at 7:01 PM, CamGTP said:

That's pretty normal in my opinion. They try to run a warmer temp to reduce drag for that .1 mpg increase because it all matters with CAFE.

 

They offer a lower temp transmission thermostat on the 6 speed and I think 8 speeds now too, GM made it because of high failure rates to those transmissions. Not sure what the 10 speed uses.

yup that .1 mpg for the charging algorithm as well. Burn $2 less fuel over 100K miles but toss more batteries in the trash.  Oh it's a real green decision. 

[redwngr]

33 minutes ago, SFLTruck said:

yup that .1 mpg for the charging algorithm as well. Burn $2 less fuel over 100K miles but toss more batteries in the trash.  Oh it's a real green decision. 

I would argue that the batteries last longer.

[Pairofkings]

Update to my original post.  I installed the PPE thermal bypass block on my transmission.  It made a huge difference in the operating temperature.  Today while towing my 5000# travel trailer at 70MPH the trans temp was 151 degrees.   The highest temp I saw was 170 and that was while backing into my driveway.  Installing the thermal bypass block is the only change I’ve made to the transmission system. If you’re concerned about the high trans temps I would recommend considering this modification.