Grover67

Its stil going to be pretty tight getting a hose down into the bottom. The vid Z45 posted is pretty much what you're up against. Live I mentioned before about if you do it on a lift it'll be a little easier to work around than doing it off the floor, and yes it would be better to clean it out fully. It will also depend on how many miles you have on it and how much you've used 4WD. Mine was pretty clean when I changed it around 30k

Front cover takes some work to get off and you'll need a gasket as its not reusable, if you have it on a lift it'll help. Just hope most all of the gasket comes off with the cover as its not the easiest to scrape off, not sure what was used when they installed it.

Winter blend gas will show a little less mpg also

https://greendieselengineering.com/product/gm-1500-lm2-duramax-engine-trans-hot-tune/

Have they been all OEM's brakes you are going through??

I did the PPE trans oil cooler first. It held the trans temp down some but its being regulated by the bypass. I changed out the bypass with the PPE and it runs about 40-50f cooler overall winter/summer. Just got back from doing some work today at our cottage about 2hrs away. Mostly highway running 80mph, it was 80f out today and once the trans temp stabilized it runs right around 158f. Winter driving here in Michigan it runs a little cooler to a little warmer due the radiator louvers shutting/ regulating. I would just run the bypass and if needed add in the cooler.

It wasn't 100k on the LM2's, the new ones with the same belt are 200k I wouldn't even be concerned at that point.... https://www.youtube.com/watch?v=Ea5r6XAK3bk

Are using the recirculation button or is it drawing air from the outside? What is the center vent temperature coming out when on max cooling while driving? How were you reading or doing with your 45ish pressure reading and what made you think you needed to add refrigerant?

Supply issues are still a issue hard to imagine that it is... I went with new rotors and pads(aftermarket) all the way around @ 30k. Pad life was showing 88/90% and they had alot of pad left but I was getting vibration issues from the pad material imbedding on the backside of the rotors, due to what pad material gm has to use anymore.

Ya ran into the same issue when I replaced mine and couldn't reset the life monitor. Checked with a couple of local shops but they had no clue. So bit the bullet and checked with the local dealer and they got right in and reset it. They say GM does it as a safety issue and only wants dealerships to reset it.....crap

A good accurate digital thermometer and check vent temperatures to see difference, they'll be some but shouldn't be a big swing.

Yes you are correct and depending what truck you have there are different gaskets -grover67

Thought about trying a bypass to see or you just going to let the GM network do its thing? Its a easy swap.

Sounds like the bypass could be hanging up and not allowing it to open to allow fluid to go to cooler coil.

How many miles on it? Was yours using oil? Did you take off the inner cooler and clean it out and if you did how much oil did you find? thank you

Pretty easy for the most part, didn't loose very much oil either.

Did the PPE cooler on mine but found that the PPE bypass did the most for dropping the trans temp. -Grover67

Felt like more in the front but could feel the feedback throughout the drivetrain. After reading that some were having their brakes wear out prematurely I'd thought I'd investigate more. After seeing the backside of the rotor and conversing with a bud of mine that works at GM testing decided to change out the fronts first which took most of the vibration out but the rears(pic was the rear rotor) was looking like the fronts and could still feel it some, so just decided to get over with and change them out and move on. The rears are abit trickier to do than the fronts due to the electric parking brake. Never thought I'd have to change them out with such few miles and the way its been driven. Chased a vibration issue with my last vehicle but it was deeper in the front axle than I was willing to go at the time. Has your truck had anything done other than change of rubber? Level, different rims/offset, or suspension? Good luck with your quest!

If would get slightly worse and depending how much they were used. Not hard on them but when I was on a trip and went through the Appalachian MTs. and was using them more it was making it worse, felt it more at certain speeds too. Thought the same as it could be a balance or wear issue, it isn't leveled, so when I did a oil change and rotation I checked the rotors and found the buildup.

My '20 AT4 I started noticing a slight vibration before 20k and was getting slightly worse with the more miles. Found that the brake rotors were getting a buildup from the pads. Finally had enough around 30k and replaced all and vibration is gone. There was alot of pad left when I changed them and the wear indicator was at 89% front, 91% rear. The outside of rotors looked good but backside looked and you could feel the buildup. The pad material the GM is using is causing this, due to certain state regulations. Had to take the truck in to the dealership to get the pad wear indicator reset. Asked the mechanic if he has seen this issue much and he has and said just turning them won't help because its the pads. -Grover67

Check the inboard side of your brake rotors for what looks like buildup. This will cause vibration issues, it from the crap brake pads being used, thank you comi foria... -grover67

Found a Chevy RST that I liked but it had cloth seats and wanted leather. There are a few aftermarket shops that offer leather that the dealer worked with to change out and wasn't too bad. -grover67

https://www.morimotohid.com/Morimoto-XB-Backup-Light-Boost-Bar?quantity=1

Does it have the factory louvers in the front of the radiator?

Rears got changed out today, rotors looked like the fronts but not quite as bad, 93% left on wear pad indicator. A little bit different to do. Set the brakes into service mode, disconnected battery and got first side apart. Couldn't get caliper back on. Called a buddy of mine, had to use a 12v battery to retract piston fully and then was able to compress it the rest of the way to get caliper back on. Reconnected battery, took out of service mode and no codes. Will do break in procedure on pads tomorrow. So their done now -Grover67