Hagar68

Transmission is controlled by a computer. I just Wondered if there were some error messages or codes set that would lead the dealer to a problem that is preventing the downshifts and hurting drivability. I haven't been up a hill yet where I could not maintain the speed limit, AND while staying under 4500 rpm. I do not normally use cruise in the mountains as it seems to keep rpms too high.

I just added 2 additional horns. Relay tapped in to original horn wire. Mounted new horns on firewall over engine.

Another viewpoint: 8k lb travel trailer. =original TV was '13 tundra, 5.7, tow pkg, 4.3 gears =Bought '19 chevy 2500 duramax ,=15 months later, traded for 20 gmc 2500 gasser Gasser is 2000 lbs heavier than tundra empty, and on a camping trip the truck weighs 9700 lbs including 1000 lb tongue wt plus remaining 7k lb trailer wt. i'm very pleased so far with towing. haved pulled up a couple of 7% grades 2-3 miles long and was able to pass some but not all traffic, nothing like the diesel but completely respectible. First time i pulled it had some downshift burps but has done fine since then. its a little noisier than tundra but to be expected with weight and gear difference. Tow/haul, chevron 89 octane, 10% ethanol You might have the dealer see if any codes stored in engine or trx. I think i read gm completely redesigned the axles for strength, so might be hard to do gear swap I have banks idash left over from the diesel and banks said they would eventually tune this engine. I really wonder if you have a trx programming problem.

Don't they already have cold air intake?

( CHOPPERDOC:. I live in Decatur. ) 20 Gasser getting 8.5 pulling a 8k lb trailer. It's all about air drag, and that increases as the square of speed. Faster you go, less the mpg.

Bought '19 Duramax 11/19 to pull 8k travel trailer but mostly to correct a half ton way over gvwr. Kept it 15 months and traded for '20 GMC Gasser 2500. Dmax pulled the trailer great, smoother and quieter than wife's Acura. But exhaust filter made it virtually unusable in my town. So many red lights that Regen needed every 80 miles so had to drive to next town every week. Love the Gasser, pulls trailer just fine and has 2800 lbs payload vs 1800 on the diesel. Driving is fun again for me, but it was a very expensive lesson.

According to owners manual in towing section, you are supposed to change oil after break in but BEFORE towing for the first time. Just FYI.

2020 GMC 2500 SLE, gas, modest options. When I shut it off and exit vehicle at night, every outside light stays on for 30 seconds.........EXCEPT the cargo light on top of cab. Cargo lights inside the bed are even on. Is this normal? Sure isn't logical. (Cab cargo light does work from the dedicated switch. I don't have the mirror flood lights).

2020 GMC 2500 gas engine. Starts good first of the day and idles smooth in park. Idle becomes rough when put in reverse to back out of garage. Smooth idle in gear after 2-3 blocks. I live in the south but it does it hot or cold weather. I've seen the service bulletin for cold weather starts and added the suggested additional ground to throttle body but no change. Truck has only had Chevron fuel. Has done this since new. Anyone else have this issue? E

2020 GMC 2500 gas engine. Starts good first of the day and idles smooth in park. Idle becomes rough when put in reverse to back out of garage. Smooth idle in gear after 2-3 blocks. I live in the south but it does it hot or cold weather. I've seen the service bulletin for cold weather starts and added the suggested additional ground to throttle body but no change. Truck has only had Chevron fuel. Has done this since new. Anyone else have this issue? E

I changed oil on my 20 GMC at 2 months old and every grease fitting took minimum of 8 pumps from my pneumatic grease gun. Dry as a bone from the factory (built 1/20)

McGuire's quick detailer. I'm 70 and I've never seen anything work like this. Stay on and just wipe off

I have 2020 GMC 2500 gas with shutters. I have the build sheet, no snow plow prep. Build date was 1/30/20. I do not find the aero shutter option mentioned above on the build sheet. Tow pkg, 10k gvwr

I agree completely that it is not required, and that most people would not do it nor even know about it. I just mentioned it because I was very surprised to see it in the book, very unusual. This is my 7th gm truck purchased new and this OM is a lot different than the others. I estimate 30-40% of it was written by the lawyers.

The on-line Operator Manual that I find is part # 84186886C and the OM that physically came with my truck is part # 84186890A. The page numbers are different but they both say the same thing. Mine has the verbage you quoted above on page 208, whereas the on-line version is at page 204. ADDITIONALLY on page 287 of my physical manual, at the "driving with a trailer" section, it says: "-Do not tow a trailer during the first 500 mi of vehicle use to prevent damage to the engine, axle, or other parts -It is recommended to perform the first oil change before heavy towing -During the first 500 mi of towing, do not drive over 50 mph and do not make starts at full throttle" You will find this exact verbage on page 283 of the on-line version of the document under the "driving with a trailer" section. Not quite sure what "rtfm" means, but I find it good practice to learn all I can about my vehicles. Sometimes things are not as I assume.

I just traded for a 2020 GMC double cab gas 1 week ago. In reading thru the owners manual, I was very surprised to find that it says to change oil and filter AFTER the 500 mile break in period and BEFORE towing for the first time.