6.2 owner ready to jump ship to 6.6 gasser

eguzowski · September 30, 2025

I made the jump from a '24 1500 ZR2 with the 6.2L to a '25 3500 High Country with the 6.6L gas and haven't looked back, same concerns on the 6.2L and very happy to have slightly more piece of mind while towing

Edited September 30, 2025 by eguzowski

dieselfan1 · October 1, 2025

I'm not missing my 23 HC 6.2 at all. I can sleep at night now not worried about a engine failure.

This new 6.6 gasser purrs like a kitten.

Edited October 1, 2025 by dieselfan1

Chuck FB · October 1, 2025

43 minutes ago, dieselfan1 said:

I'm not missing my 23 HC 6.2 at all. I can sleep at night now not worried about a engine failure.

This new 6.6 gasses purrs like a kitten.

Because you commented on how it runs, did your 6.2 have any characteristics that caused you to think it was not firing smoothly or perhaps the double exit piping and muffler allowed more sounds to come out ?.

I assume you've noticed the ride isn't there though from what you have been used to ( although your roads may be way better than some places ), between hard tires if you are carrying the door stickers max weight pressures, and HD trucks have a lot more spring under them than a half ton by a mile. That is usually the gripe with those that have been so used to the ride of half tons and suv's.

As to the theme of it being a new truck and just suggestions based off of what I and others have found, it wouldn't hurt when you have a chance to check the oil levels of the rear and front diffs and the transfer case as all of mine were down, the rear diff was the most under filled but I topped them all off. Also and again just a good practice is to drop your factory engine oil much sooner that a normal oil change period.

Edited October 1, 2025 by Chuck FB

KARNUT · October 1, 2025

Make sure you check first. Some rear end fills for instance are not untill they run out anymore. I had one that was an inch down from the fill hole. I’m glad I checked first.

Chuck FB · October 1, 2025

26 minutes ago, KARNUT said:

Make sure you check first. Some rear end fills for instance are not untill they run out anymore. I had one that was an inch down from the fill hole. I’m glad I checked first.

That was the same with my rear diff, I used a thin bent wire to 90 degrees and measured it and it was exactly 1 inch down and that was after the diff had sat and was cold settled oil. The sad part is I had been told by the service manager that they check all fluids now since they had a couple of diffs fail on them the year before from you guessed it, low fluid level but the fact is the shop either did not check it on my truck or if they did, did not add any oil. If the service manager was giving me a good line he knew was not true as to their checking fluids or the shop was telling him they had performed the check and did not, who knows. Long and short of it was that I was thankful I did not take anyone's word and checked myself and corrected the levels. I did not bother going after the dealer and asking for a free quart of gear oil for the diff although I could have but did not want that conversation, I just used my supplies and topped off the drive line components and now I know they are full. I never said a word to them about it as it would do no good anyway and fly in the face of the service manager and that would not help me out in the future.

dieselfan1 · October 2, 2025

12 hours ago, Chuck FB said:

Because you commented on how it runs, did your 6.2 have any characteristics that caused you to think it was not firing smoothly or perhaps the double exit piping and muffler allowed more sounds to come out ?.

I assume you've noticed the ride isn't there though from what you have been used to ( although your roads may be way better than some places ), between hard tires if you are carrying the door stickers max weight pressures, and HD trucks have a lot more spring under them than a half ton by a mile. That is usually the gripe with those that have been so used to the ride of half tons and suv's.

As to the theme of it being a new truck and just suggestions based off of what I and others have found, it wouldn't hurt when you have a chance to check the oil levels of the rear and front diffs and the transfer case as all of mine were down, the rear diff was the most under filled but I topped them all off. Also and again just a good practice is to drop your factory engine oil much sooner that a normal oil change period.

My 6.2 ran fine also. I put 0w40 in it in May and in noticed it was quieter though.

I also had a Corsa catback setup so it was always louder.

I'm planning on changing the oil after it hits 500-600 miles. I'll check the diffs and TC then.

What's everyone using for oil besides amsoil?

Edited October 2, 2025 by dieselfan1

Chuck FB · October 2, 2025

4 minutes ago, dieselfan1 said:

My 6.2 ran fine also. I put 0w40 in it in May and in noticed it was quieter though.

I also had a Corsa catback setup so it was always louder.

I'm planning on changing the oil after it hits 500-600 miles. I'll check the diffs and TC then.

What's everyone using for oil besides amsoil?

It certainly makes one wonder when an originally approved viscosity was used and then in this case a different viscosity became approved, but a noticeable difference in engine sounds results. What is now being cushioned from being audible that was not with the thinner oil. Its not like these engines have built in rocker arm clearances like a lot of industrial diesels or old gasoline engines over the years or the Japanese gas engines with the overhead valve train with the same manual adjusted rockers that one could hear tapping away under the valve cover by design.

Exhaust would certainly take away some from being able to detect the engines sounds, the L8T with its 45 gallon drum sized muffler does a pretty good job of keeping the truck quiet once it idles down after its initial high idle warm up. To me as well it just seems like a well oiled sewing machine under the hood at idle.

At this point for oil and its not like I have any reason for a bold claim about the oil but have been using Mobil 1 Truck/SUV 5W-30 and its claimed by Mobil of course to have a slight boost in anti wear additives and has the dexos1 gen 3 authorized approval. I am using the GM PF63 filter of the latest part number change up that would have the higher bypass pressure over prior filters of the same GM designation ( some dusty parts corner store may have old PF 63 or other brands with the prior spec ).

rdonarski · October 2, 2025

10 hours ago, dieselfan1 said:

My 6.2 ran fine also. I put 0w40 in it in May and in noticed it was quieter though.

I also had a Corsa catback setup so it was always louder.

I'm planning on changing the oil after it hits 500-600 miles. I'll check the diffs and TC then.

What's everyone using for oil besides amsoil?

I've been using Kirkland in my car, truck, and SUV. Before that, I always used Mobil 1 (since 1987). I bought a new skid steer back in 2000 and have always used Amsoil in that. I'm thinking as I deplete my Kirkland inventory, I'm going to switch to all Amsoil. I live less than 50 miles from the Amsoil factory (can pick it up there). I've also swapped my car and SUV transmissions to Amsoil. With the price of engines and transmissions, oil is cheap.

Edited October 2, 2025 by rdonarski

rdonarski · October 2, 2025

On 9/29/2025 at 1:00 PM, KARNUT said:

We had six. My father pushed diesel. Then the 6.5 giving GM another go. Being that we were a family that purchased vehicles at the same place at the time we were friends with the owner of the dealership. And the people who worked there. They advised us not to go past the warranty with the 6.5. At the time it was 100K miles. I went with a 91 Dodge diesel along with two brothers dad went with a 7.3 Ford. We all pulled goose neck trailers, me mostly. Up until we sold our ROW clearing business and stay with the our equipment building and sales business. We worked our trucks hard and modified them. Later we had an 05 Ram diesel that ran 11s and was a daily driver. After our sales business grew we couldn’t haul our equipment with p/ups anymore we went to gas trucks about the time emissions neutered them. With the exception of one brother who went with the clearing business we sold. He and his son who had the 11 second Ram run over 19 ROW crews. They eventually went all Ford diesel and now only use them for heavy work. Using mostly gas some GMs, mostly Fords. Diesels with the added emissions just became too costly most needing delete at around 100K miles or emissions over haul. Up until the mid 2000s Fords and Ram diesel were hard to kill with the exception of the Ford 6.0. Ram had some issues in the mid 2000s. We were lucky to just missed those. My mother still drives her 2000 7.3 refusing to part with it. My late father’s 98 Ram is still going both pretty bulletproof. The Ford a little less than the Ram. The service trucks at our equipment dealership are all gas. A place that was all diesel has not one today. Not one new Chevy. Two Raptors one R, a Shelby Super Snake. A modified Reg Cab Ford with the blower package and one TRX. I was the only remaining Chevy driver when I retired. Now I drive a Ridgeline mostly. An Avalanche some. My grandson is taking it over.

My son's 1st new vehicle was a 98 Ram. Using Mobil 1 oil, it used a quart every 1000 miles. He traded for a Chevy in 2000 and never looked back. I've been running all Honda cars and SUVs since the mid-90s and have been very happy with them. My daughter bought a new CRV in 2012 (on my recommendation). It used a quart every 500 miles and Honda called that 'standard'. She switched to Mazda in 2016. That experience has me thinking about changing brands for my next vehicle. I've gotten lazy and don't check oil often. Just count on my vehicles not using it. One bad experience will definitely sour me on a brand.

KARNUT · October 2, 2025

3 minutes ago, rdonarski said:

My son's 1st new vehicle was a 98 Ram. Using Mobil 1 oil, it used a quart every 1000 miles. He traded for a Chevy in 2000 and never looked back. I've been running all Honda cars and SUVs since the mid-90s and have been very happy with them. My daughter bought a new CRV in 2012 (on my recommendation). It used a quart every 500 miles and Honda called that 'standard'. She switched to Mazda in 2016. That experience has me thinking about changing brands for my next vehicle. I've gotten lazy and don't check oil often. Just count on my vehicles not using it. One bad experience will definitely sour me on a brand.

I’m gradually going Honda. Never bought one new. They always seem to have more road noise. They seem to be addressing that. I cruise the dealer website almost daily. My local Honda dealer has certified pre own vehicles with as much as 145K miles on them. That says a lot.

rdonarski · October 2, 2025

1 hour ago, KARNUT said:

I’m gradually going Honda. Never bought one new. They always seem to have more road noise. They seem to be addressing that. I cruise the dealer website almost daily. My local Honda dealer has certified pre own vehicles with as much as 145K miles on them. That says a lot.

I agree on the road noise and that alone may be cause us to switch. Looking for more comfort in our old age. I've bought 3 used and 2 new. I currently own a 2003 Accord that we bought new and has been a great car. It won't do my driveway in the winter though, so that caused us to buy a 2016 CRV in 2017. At that point, the 2003 wasn't worth much on paper, and since I had taken excellent care of it, and even limited its winter driving, we decided to keep it. It's our main vehicle in the summer (parked in the winter). It had been a lease vehicle. It's also been a good vehicle and doesn't use significant oil.

KARNUT · October 2, 2025

15 minutes ago, rdonarski said:

I agree on the road noise and that alone may be cause us to switch. Looking for more comfort in our old age. I've bought 3 used and 2 new. I currently own a 2003 Accord that we bought new and has been a great car. It won't do my driveway in the winter though, so that caused us to buy a 2016 CRV in 2017. At that point, the 2003 wasn't worth much on paper, and since I had taken excellent care of it, and even limited its winter driving, we decided to keep it. It's our main vehicle in the summer (parked in the winter). It had been a lease vehicle. It's also been a good vehicle and doesn't use significant oil.

Counting the Acura we’ve have 4. No oil users. Funny though I recently got a letter raising the warranty on the 16 odyssey to 160K just as it turned 160k. Some had oil burning problems. If the wife ever decides to part with the Genesis we’ll probably go with an Accord or Acura. I with all the brands and types of vehicles I’ve experienced. The Odyssey is close to perfection. The only vehicle I’ve owned I never seem to get bored with. You have to drive one for awhile to get it. The soccer mom theme is a holdback. The Ridgeline is pretty cool. I understand why they aren’t big sellers as good as they are. It has full-size trunk fuel mileage. My 14 GMC did better. If it wasn’t for cylinder deactivation I’d be driving one now. The nice thing about Hondas you can buy one used with no fear. It used to be that way with GM trucks. Not anymore.