5proms

Robert, sorry I made some bad assumptions about your 17 premium. 3000rpm at 65 is a little high for sustained cruise like you said. It’s a shame the 5.3, 6 speed combo doesn’t work better together for towing. Our 05 Yukon Xl with the 5.3 only had the 4 speed and in 3rd at 65mph it was spinning at 2500rpm, pulled the Airstream well in the flat, Only needed 2nd to maintain speed up some hills. I highly recommend the 6.2l ecotec with the 10 speed. Buckets of torque starting at 2000rpm and plenty of gear choices for towing. Better fuel economy than our old 5.3 if you can believe that!

With a 10 speed tranny, (which I’m assuming you have) you don’t need to change the rear axle. Put it in manual and select the gear that keeps the engine in the ‘sweet spot’. We have the 8 speed in our ‘15 ESV and we pull a 7000 lb, 32’ Airstream. I keep it in 6, and at 65 mph, it’s about 2200 rpm which is right in the torque curve and steady transmission temps at 175. It doesn’t shift much at all while cruising which is what generates excess heat for automatic transmissions. MPG between 11-13.

I only run Michelin's on my Tow Vehicle, 05 Yukon XL, total mileage on truck 240K. Have 60K on current set, only rotations required, still good amount of life left. ?

Don't know what else to tell you bro', but you have a very challenging problem. You are right, it should work the right way all the time. Good Luck! KP

On our '05 Yukon XL, I replaced all the rubber hose caliper lines with stainless steel braided lines at the 180K mile point. Brought back a nice hard pedal, no more 'ballooning' of the rubber hoses. It was a kit from Summit Racing.

I'm having the same issue with our 2015i Escalade ESV. Same tranny, 8L90E. It has had all the Field Action Recall items accomplished related to 8L90E shudder and driveability problems. But, it still hard shifts between 1st and 2nd under very light accelerator pedal push. If I 'lean' into it, punch it or we are towing, it shifts just fine. For background reference here are the service bulletins from 2015 related to this transmission: N150396 15396 HARSH SHIFTING WHEN STARTING IN LOW TEMPS - Corrective action was Trans Control Wiring Harness Replacement N150389 15389 TORQUE CONVERTER CLUTCH (TCC) SHUDDER - Corrective action was Trans module reprogram Then in 2018 the dealer performed 8480478 Flush and Drain fluids for Trans shake or shudder. Don't know if GM applied all these updates to 2017 models, but there is obviously a history with this transmission.

Replace both battery cables, easy fix.

Hey KC, I have an '05 Yukon XL with 5.3 flex-fuel. Volant cold air intake, Hedman shorty headers, original Y-pipe with cats, Flowmaster cat-back, never a single code. The drop-tube option with the Volant allows for airflow right from the bumper area to be 'pushed' into the air filter box, with this option I see MAF temps only a degree or two above outside ambient. My tuner is just a Bully Dog GT, I flash for premium when I'm towing, zero pinging with this timing and at least 91 octane fuel. 235K and counting... Enjoy!