Transmission temperature 10speed with 3.0 LZO Duramax

Grover67 · May 7, 2023

For anyone that installed the PPE bypass block did you run in the winter months yet? Will this be a concern being as cold as it gets in the northern states? I know the louvers would help with this some but were there any issues or codes thrown?

-Grover67

mjonesjr84 · May 7, 2023

2 minutes ago, Grover67 said:

For anyone that installed the PPE bypass block did you run in the winter months yet? Will this be a concern being as cold as it gets in the northern states? I know the louvers would help with this some but were there any issues or codes thrown?

-Grover67

I live in Southern Indiana and ran the PPE bypass block this winter. I never had an issue with it.

BB68 · May 8, 2023

On 4/9/2023 at 5:34 PM, Pairofkings said:

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.

FYI my 10 speed was at 130-140 running down the interstate today. (EDIT I have max trailering)

I haven't seen that kind of temp since my 15. The 18 8 speed was never that high

Edited May 9, 2023 by BB68

Grover67 · May 8, 2023

Looks like the 10L80 also has a internal bypass also.

Fuss behind GM’s 10-Speed transmission

The aim of the GM 10L80 is to provide performance and efficiency. Its automatic mechanism keeps the engine in the best power band when the driver accelerates. Maximum fuel economy is employed when upshifted to any one of the three overdrive gears. Their gear spacing is meant to be unsurpassed; the engine’s RPM only drops about 20% as the transmission changes gear. The gear ratios are supposed to make the downshifts and upshifts lightning fast. When the engine is in the optimal RPM range, the 10l80 can operate almost as efficiently as the CVT transmission.

Since you can choose ten forward gears, this transmission can reduce an engine with high horsepower fuel consumption. But their gearing isn’t the only reason behind the 10L80 maximizing efficiency. The lost energy is reduced as only 2 out of 6 clutches stay open simultaneously. It has an internal thermal bypass that allows transmissions to warm up quicker, which reduces fuel consumption. Fluid pressure is maintained through an off-axis pump which can change the displacement according to the load. A second pump helps maintain fluid pressure when the start/stop function is activated.

ExYukon · May 9, 2023

Just an FYI. I have a 2023 Silverado 1500 with the 10 speed and 6.2L. It also has Max Trailering. The tranny temp sticks like glue to 144F in normal highway driving. With my 7100 pound travel trailer, it's usually 144-150, sometimes 153. On Raton Pass northbound with the trailer, it topped out at 162. It got into the low 170s a couple times when I was in stop & go rush hour traffic with the trailer.

I don't know if those low temps are due just to the bigger cooling capacity, or if the thermostat set points are also different with Max Trailering.

BB68 · May 9, 2023

10 hours ago, ExYukon said:

Just an FYI. I have a 2023 Silverado 1500 with the 10 speed and 6.2L. It also has Max Trailering. The tranny temp sticks like glue to 144F in normal highway driving. With my 7100 pound travel trailer, it's usually 144-150, sometimes 153. On Raton Pass northbound with the trailer, it topped out at 162. It got into the low 170s a couple times when I was in stop & go rush hour traffic with the trailer.

I don't know if those low temps are due just to the bigger cooling capacity, or if the thermostat set points are also different with Max Trailering.

I have the same here, and finding similar temps under non-towing conditions, I never looked when I picked up the boat.

I have noticed I dont have any shudders behind the grill like my '18 had, and I also wonder about the t-stat

Grover67 · May 9, 2023

I installed the PPE transmission cooler last week and did some towing over the weekend. Overall the temp stayed down and didn't climb like with the OE trans cooler, but wasn't in the range of you with the Max towing package or with the PPE bypass valve installed. I'm thinking the trans thermal bypass on the Max tow package has a lower setpoint opening. Anyone have the part number for the GM Max tow package thermal bypass valve for the 10L80? Might try one before going with the PPE.

-Grover67

Sneaky pete · May 19, 2023

My 2020 elevation 10 speed runs 145 all day long with no load. 175 with 32 ft. Tt.

MrMagloo · May 19, 2023

This all sounds very odd based on what I am seeing. I just picked up my 2023 RST 3.0L NHT (Max Tow) and while I haven't towed anything yet, just around town and mixed highway, I am seeing averages in the 190 degrees range once fully warmed up. I asked the dealer and they said this was normal, that there is a thermostat that maintains that temp to maximize efficiency? This explanation and comparison to your experiences seems not to reconcile? Fwiw, I have the MQC trans if that makes any difference?

redwngr · May 20, 2023

Around town, especially with lots of stops and starts will always settle at higher transmission temps than when at steady speed on the highway.

Airflow is required to make the cooler work.

Torque converter during starts and lots of shifting at low speeds all create more heat.

Grover67 · May 21, 2023

Installed the PPE bypass this past week. Ran it today a couple hundred miles, 65-75mph range, ambient was 55-66f, wasn't towing and not much stop /go driving backroads and expressway, trans temp 147-153f. So with the bypass it dropped the trans temp about 25f from what it was running just with the PPE cooler installed. Will be interesting once the cold winter temps come to see how well the internal transmission regulator works with what I've done but at least if it dosen't it can be changed out real easy. Would be nice to know what the Max tow package external bypass regulator temperature opening is set for vs. the standard bypass.

-Grover67

Edited May 28, 2023 by Grover67
added

MrMagloo · May 26, 2023

Does anyone know what the desired temp range the MQC is designed for? If they have a thermostat like the dealer claims, and they are designed to run in the 180-200 range, I wonder if there are any negatives to running them lower with the PPE Bypass. If not, I'm wondering with the Max Tow (with the larger Trans Cooler already) the hot ticket might just be to stick with the stock cooler and go with the Bypass. But again, I wonder if 140-160 might be too cold and cause issues down the road? Imho, I'd be more comfortable if the result was more in the 160-180 range.

BB68 · May 26, 2023

On 5/26/2023 at 8:51 AM, MrMagloo said:

Does anyone know what the desired temp range the MQC is designed for? If they have a thermostat like the dealer claims, and they are designed to run in the 180-200 range, I wonder if there are any negatives to running them lower with the PPE Bypass. If not, I'm wondering with the Max Tow (with the larger Trans Cooler already) the hot ticket might just be to stick with the stock cooler and go with the Bypass. But again, I wonder if 140-160 might be too cold and cause issues down the road? Imho, I'd be more comfortable if the result was more in the 160-180 range.

Its all about cafe standards, warmer oil has less resistance.

The cooler you can keep a transmission the longer it will last.

EDIT I need to add that I looked at many window stickers comparing EPA fuel mpg ratings and the funny thing is it didn't matter on what tow package or gears for a 6.2 for mpg unless they have lift kits which is understandable. So why do they need different trans temp thermostats????

Edited May 28, 2023 by BB68

repairman54 · May 27, 2023

Just pulled my boat, 3500 lbs, with my standard tow 6.2 in the mid '70's outside temp. Hilly terrain and at 65 mph saw a max temp on a long pull of 185, dropped back down to the 150-160 range on the flats / slight hills.

2x on cooler is better.