Grumpy Bears 2015 Silverado 2WD

[Grumpy Bear]

12/03/2021

 

Haven't posted a 'fresh' photo in awhile. So I gave her a bath and snapped this in the parking lot. Yea, that's a scuff in the front bumper.   Yes this is her worst side.

 

Local car wash has been bough out and the new owner has done some major repairs and upgrades. Did a nice job me thinks. In a few months she's 7 years old.  Think I'll keep her  

 

Edited December 4, 2021 by Grumpy Bear

[customboss]

Simple and clean, love it.  

[diyer2]

Pride of ownership makes a big difference, not only for looks. Why we do maintenance. 

[Grumpy Bear]

New Transmission Thermostat Ordered

 

12/19/2021

 

Uncertainty over the exact specs for the new GM 6L80E TBV had me in a wait and see space. The advertised spec of 70C (158 F) printed on the part indicated by all other manufactures of thermostats such as Stant and Gates this would be the 'cracking' temperature. IF that were the case then it would have a fully open temperature likely 20-25 F  higher with a stabilization temperature of perhaps 163 - 168 F with a tolerance of +/- 3 F and while under 175 F by most sources says all good in the neighborhood...me...not so much. I like a lid on things at 160 F. 

 

Then I ran across a the GM-Techlink dated Sept 30,2021 and read this: https://gm-techlink.com/?p=15389

 

[Quote] A new TBV is available that has a cooler operating temperature. The previous TBV had a full-open temperature of 194°F (90°C). The new TBV has a full-open temperature of 158°F (70°C).

 

The new TBV can be identified by the “70” stamped into the bottom of the valve. (Fig. 9) The “70” stamp is visible on the valve when it is installed on the transmission. [End Quote]

 

Well then, that squared with a report from a forum member (@11bravoZ71) who noted in the "6L80 Trans pill flip maintenance question" that the pill itself is stamped 135 F and this that pill installed in his 8L90E ran down the road between 140 - 160 F and right in line with my trucks cooler thermal limit. That is; pill flipped on a 95 F day it will run 55 mph at 163 F ATF all day. Perfect and sets a 140 F floor on the fluid which will help in the early spring and late fall. She doesn't get out much in the winter due to my strict no salt ban. 

 

So today I ordered GM#  86774933 per Bulletin #21-NA-199.

 

Only part number they have and it will NOT be the right body as the line coupling on mine is not the quick disconnect. No worries. I have the original body in a box and will simply swap the pill from then new into the old and install. 

 

It was my experience with the original 194 F unit that on hot days it would run closer to 225 F and if that happens with the new unit it would mean they restrict flow and I will try a secondary cooler inline with the one in the radiator or splice in an Improved Racing 145 F thermostat with more flow capability. I WILL have my cake and eat it too.  I could even use this cooler one in winter and swap out the bypass body in the summer. Not but 5 minutes work. 

 

It will be interesting to plot this new unit to the bypass system for a years worth of seasonal change. 

 

Edited December 20, 2021 by Grumpy Bear

[Grumpy Bear]

December and Year End 2021 Fuel Report

 

12/31/2021

 

December? None used. Parked.  

 

However, for the year 2021 we have 28.45 mpg. Second best year. Lifetime running average 27.76 mpg. 

 

BTW the new transmission thermostat arrived a few days ago. I'll install when I get the time and the weather is favorable.  I'll start plotting the new curve then. Just looking for a decent floor.  

 

 

 

Edited January 1, 2022 by Grumpy Bear

[Grumpy Bear]

January 2022 Fuel Report

 

She's sleeping 

[Grumpy Bear]

February 2022 Fuel Report

 

329 miles using 14.176 gallons of fuel = 23.21 mpg. 

 

Actually I filled up on February 21, 2022, a tank that was last filled November 30, 2021 so this is a tank for three months. 

 

Lifetime history graph. 

 

[Grumpy Bear]

152,000 Mile Service

 

3/2/2022

 

The point of this project is to set a floor on the ATF temperature during cold weather operation. 

 

Installed transmission thermostat GM#  86774933. Stamped 70 C full open temperature. Minimum regulating temperature by measurement has been so far 138 F (59 C). Pretty standard 20 F spread. 

 

 

Edited March 12, 2022 by Grumpy Bear

[Grumpy Bear]

Transmission Cooler Data

 

Useful link

https://www.onallcylinders.com/2017/05/04/transmission-cooler-guide/

 

Take note of Earl Performance take on ATF temperatures.

 

 

 

 

Edited March 12, 2022 by Grumpy Bear

[Grumpy Bear]

Trans Temp Update

 

3/12/2022

 

Turns out it isn't so much a floor as it is support. It was 10 F today so went for a ride down I-39 instead of my road course and replotted the data. It took 40 miles to reach a stable temperature of 127 F traveling a steady 55 mph. When I stopped to turn around it spiked 131 F but within a few miles recovery was back to 127 F. Once I returned to the primary highway it rose slightly and in town before arriving home to the low 140's. I also tried a change of speed. 65 mph increased the temperature but within a short while after returning to 55 mph so did the temperature. So...yea....load matters. 

 

The pill flip gets it to 110 F much quicker but after that it's time in the saddle. Starting next week the local temperatures will be on the rise and data collection will resume over the summer. I would hope the slope would eventually meet that of the orange plot of the current water thermostat. The water thermostat can only have any effect on transmission temperature after the cracking temperature. Which you can see in the data is roughly 138 F. 

 

 

(Chart updated in new post)

 

Edited March 15, 2022 by Grumpy Bear

[Grumpy Bear]

Trans Thermostat Update

 

3/14/2022

 

Two more points added today. Weather has been cooperating.  I like where this is going. 

 

[New chart in next post]

 

To get each data point I run down the Interstate about 50 miles at a steady 55 mph. It will top out somewhere in the last ten miles depending on wind direction and speed. When I get off the ramp to turn around the temperature spikes. I run back that the same speed until it reaches it's lowest recovery temperature from the spike and that is the value I plot. 

 

Recovery time has been really good so far. A few minutes. I expect it will be as long as there is a cushion between the recovery number and the value for that air temperature as plotted on the orange line or 158F, the full open temperature of the unit (70C). We don't get to many days over 95 F in my area but I do want some cushion for trips to the desert and Rockies. Yea, thinking out loud. 

Edited March 17, 2022 by Grumpy Bear

[Grumpy Bear]

Trans Thermostat Update

 

 

3/17/2022

 

 

 

Able to add points above 65F. As the TBV gets more open there is a difference between ATF temperatures running into the wind vs wind at her back. Instead of a point it is a range that is widening. About 4 F +/-. I'm plotting the hotter end of the spectrum. Recovery time takes longer as the reserve cooling is used up and the valve throttles more open. Enough data to now project a trend.

 

(New chart in later post)

 

I've noted that when others have done this modification on trucks with the NHT option this curve just flattens out around 145F. Those trucks having a second air cooled exchanger in series and after the tank mounted unit OR as a stand alone a a case or two where an aftermarket exchanger has been placed in service. 

 

Another notable note is mileage has improved between 45 and 60 F air temperature. I really wasn't looking below that point nor did I have enough miles at those temperatures to collect enough data to process. Point is, it's acting according to plan. This extends the driving range earlier into the spring and later into the fall. Still won't run her in the salt.  

 

It may be awhile before we get more days like this. I think what I'm going to do is continue to monitor and plot as the data comes in and draw out this curve at least past 80 F air temp. Hopefully data higher than that. I'd like to see what happens after the TBV is wide open (158F) Then add a cooler whose size will be determined by the data collected above that point and repeat this in a fourth line simulating the factory NHT. Should it actually stay under 160 F when over 90 F we may be done here. We'll see. 

Edited April 23, 2022 by Grumpy Bear

[Grumpy Bear]

March 2022 Fuel Report

 

4/4/2022

 

846 miles on 31.634 gallons = 26.74 MPG

 

Slow month. Working with Dizzy. 

[Grumpy Bear]

Trans Thermostat Update

 

4/22/2022 (newer chart available)

Edited May 11, 2022 by Grumpy Bear

[Grumpy Bear]

Trans Thermostat Update

 

4/23/2022

 

I reposted the above graphs after todays outing. 84F highest observed temp. 25-30 mph south wind. It did a few things I expected to do today and it did a few things I didn't expected. 

 

The TBV valve absolutely restricts total flow. Figured on that. Final overall ATF temps are higher.  What I didn't see coming was the air to fluid relationship change. Right around 70 F ATF will be about 80 F over air temp and this is not as precise as it looks in the graph. It is now something it never was. Sensitive to load and actual wind speed. Actual wind speed is road speed plus or minus wind speed. That is a 20 mph head wind is a plus and a 20 mph tail wind is a negative to the road speed. The numbers in the graph past 70 F are the median value of a range. Range does not exist below the TBV fully open temperature. I runs hotter with a tail wind even thought load for that speed is lower. This range spread by 84 F is about 5 F +/-. 

 

I'm going to need more cooler. That is just a fact. But before I add one I'm going to dilute the coolant to raise the heat capacity. Something I've done before. 

 

Additional note. Sitting in drive through today I turned on the AC remembering that at the end of the season last I learned that doing so lower the fan toggle temperature. Does this to protect the condenser from freeze over. Those fans were on by 185 F holding the oil temp to the same as running 55 mph or mid 190 F range. ATF temperature never rose above 176 F. Not ideal BUT way better than the stalled traffic numbers I got a few summer ago before I knew this. All fluids making over 215 F.