Report on Chevy/GMC 1500 with 6.2 engine and Max tow pack

[gypsydad]

Originally Posted by gandttimes

You do know that this is a discussion about real trucks, not F trucks don't you?

Of course; we all know that this is a discussion about GM...but a little levity doesn't hurt, right? (besides; that was not a bad suggestion he had!)

[gandttimes]

Originally Posted by gypsydad

Of course; we all know that this is a discussion about GM...but a little levity doesn't hurt, right?[emoji38] (besides; that was not a bad suggestion he had!)

Not from what I've been reading on other threads about the "death wobble" and now the new recall of thousands of F trucks for the fire issue.[emoji4]

[gypsydad]

Originally Posted by gandttimes

Not from what I've been reading on other threads about the "death wobble" and now the new recall of thousands of F trucks for the fire issue.[emoji4]

Turns out, the "death wobble" is not unique to Ford if you read a bit more...posts about RAM, GM, and even Jeep having same issues...not good for any of us. Fire issue related to head bolt heater...fortunately, I had mine removed...don't need it where I winter. Not good to have any issues, but happens to them all.

[Isuzusweet]

Originally Posted by gypsydad

Turns out, the "death wobble" is not unique to Ford if you read a bit more...posts about RAM, GM, and even Jeep having same issues...not good for any of us. Fire issue related to head bolt heater...fortunately, I had mine removed...don't need it where I winter. Not good to have any issues, but happens to them all.

Actually the latest fire recall is due to the seat belt pretensioners catching the interior carpet on fire in the event of a collision, along with speed control computer fires, block heater fires, death wobbles, tire failures, Chinese parts.......the list is endless with Ford's.

I'd rather Government Motors than Chinese Motors wearing a Ford emblem.

Cheers
Sidekick Tony

https://www.thedrive.com/news/28605/...so-far-in-2019

[gypsydad]

Originally Posted by Isuzusweet

Actually the latest fire recall is due to the seat belt pretensioners catching the interior carpet on fire in the event of a collision, along with speed control computer fires, block heater fires, death wobbles, tire failures, Chinese parts.......the list is endless with Ford's.

I'd rather Government Motors than Chinese Motors wearing a Ford emblem.

Cheers
Sidekick Tony

https://www.thedrive.com/news/28605/...so-far-in-2019

Are you talking 1/2T or 3/4-1T?? There are recalls from all the Mfgrs, including GM! This is just one headline I saw of, many on the web, if you are interested.
"The 324,226 trucks recalled in the U.S. are the 2017-2019 Chevrolet Silverado 2500/3500; the 2019 Silverado 4500HD/5500HD/6500HD and the 2017-2019 GMC Sierra 2500/3500."

No one likes recalls or issues on their TV....nor on their AS! Good to have access to this data and to keep up on what is happening to our TV's!

I apologize for getting too far off topic...end of my posts here.

[nvestysly]

One of the issues that has annoyed many of the Sierra/Silverado 1500 owners with the max trailering package is the propensity for the rear end of the truck to feel bouncy. Owners get a sense of this when going over speed bumps as well as porpoising when towing a trailer. I originally perceived the bounce to be an underdamped shock absorber design and upgraded to Bilstein shocks. The shocks made a slight improvement to the seat of the pants measurement but the bounce persisted.

Somebody on this thread hypothesized that the bounce resulted from and under-sprung rather than underdamped system. That has had me thinking for many months about what I might do to our truck to change its dynamics.

In an effort to minimize the bouncy issue I purchased the SuperSprings SSA28 and finally installed it today. A short drive around the neighborhood, over several speed bumps, indicates the bounce has been dramatically reduced, possible to the point of unnoticeable. Time will tell. Haven't driven at highway speeds yet. We won't have an opportunity to tow the trailer for another month or so. I'll report back on the experience.

Bear in mind the SuperSprings system in no way increases the weight carrying capacity of the truck. There's no way to fudge the axle weight ratings, gross vehicle weight ratings, etc. The SuperSprings literature indicates they provide a product that restores ride height and does not increase capacity.

The entire installation was pretty simple and took about 2 leisurely hours. You could get get'r'done in about 30 minutes if you're ambitious. Here's a YouTube link describing the installation. Please overlook the SOB truck used in the video. The SSA28 fits several 1500 series trucks.

https://www.youtube.com/watch?v=LPTYI0VuP9Q

[pontzdav]

I was happy to find this tread. I have towed my FC30 for 40,000 plus miles with a Silverado 6.2 Max Tow. For 99% of this miles I was pleased with the rig. However, certain bumps, esp bridges and overpasses, the proposing happens. It can be a bit frightening at highway speeds and requires an immediate slow down / brake application. I recently traded my truck for a 2500 which does not porpoise. But I’m glad to know there is a fix for the 1509. Thank you.

[dznf0g]

I have found the, not only installing bilstein shocks helped, but slightly adjusting WD eliminated what you are talking about. What I discovered is that, depending on how the AS and truck is loaded, that I am just barely, or marginally seated in the secondary spring leaf. When this occurs, a largish undulation "bounces" the truck off the secondary leaf...kind of like a trampoline. I have a Haha, with screw Jacks. Just 3/4 of a turn many times eliminates the bounce. Could be more or less wd.
I have wondered, but never looked to see if there are thicker leaf end insulators available aftermarket.
Theres plenty of spring capacity. I have never even had the auxiliary springs (formerly know as jounce bumpers) contact their pockets when fully loaded. (No witness marks)

[nvestysly]

Our 2018 (purchased on January 1, 2019) only has 23k miles. About 3k miles ago it began to develop a periodic "shudder." Initially the shudder was very mild. I almost seemed as if the tight suspension/shocks were transmitting slight road imperfections through the chassis and into the truck. It didn't take long to realize it was the drivetrain, not the suspension. But it still wasn't obvious what was going on. We don't drive the truck much so it was not really on my RADAR screen to determine what was going on.

Late last year we began making nearly weekly trips back and forth the same 50+ mile stretch of interstate highway. On the 3rd or 4th trip the shudder began to be more noticeable and I was recording mental notes about how to convey the issue to the mechanic. It occurred to me the shudder did not occur when the vehicle was cold - not freezing versus high ambient temperature - I'm talking about engine/transmission temperature. I noticed the shudder became much more obvious when the transmission fluid reached 120F and higher.

The shudder felt as if the vehicle was going over undulations in the road. Much like going over very worn rumble strips as you approach a stop sign. I stress - very worn, very slight rumble strips.

So I finally took a few minutes to do an internet search. Sure enough, there's a Technical Service Bulletin on the subject of transmission shudder. See attached PDF file.

The local dealership performed the recommended transmission flush today. We'll see how this plays out. GM indicates that many of the prior "fixes" such as valve bodies, torque converters, etc. may not be needed. It remains to be seen if the fluid flush and replacement with a new type of fluid is the answer. I'll report back.

[pontzdav]

I had a similar issue with my 2015 6.2 max tow. Dealer did the flush, then replaced torque converter, and reprogrammed the controller. So. After two warranty visits it was all fixed and never returned. Hope you have good results as well.

[DC Bruce]

I had the exact same symptoms on my 2015. Dealer did a flush and reflash under warranty. Problem solved. I now have 117,000 miles on the truck. I still have concerns about the 8-speed, because GM discontinued it a year or two after your truck, and my 2015 was the first use of that transmission. We’ll see how it goes. . .

[Steve Bryant]

Originally Posted by DC Bruce

I still have concerns about the 8-speed, because GM discontinued it a year or two after your truck, and my 2015 was the first use of that transmission. We’ll see how it goes. . .

GM didn't replace the transmission because of problems, as this change had been in the making for several years. In fact, the 10 speed transmission for rear wheel drive vehicles was a joint venture between Ford and GM. Each manufacturer makes their own slightly different version of this transmission design, but they developed the design together. Read here if you'd like to find out more. There are a number of similar articles on the ten speed that you can read, if curious.

[dznf0g]

I retired so I really have an aversion to paying attention, but i thought the 8 speed was still used as standard on the work truck trim and G van.

[Steve Bryant]

Originally Posted by dznf0g

I retired so I really have an aversion to paying attention, but i thought the 8 speed was still used as standard on the work truck trim and G van.

You're right, I just checked the GMC website and the 8 Speed is still used on the 4.3 L and the 2.8 L Duramax van. The 6.6 L is paired to the 6 Speed transmission.

[dznf0g]

Originally Posted by Steve Bryant

You're right, I just checked the GMC website and the 8 Speed is still used on the 4.3 L and the 2.8 L Duramax van. The 6.6 L is paired to the 6 Speed transmission.

Ya know why?

[subfan1]

We had a 2018 GMC Sierra Denali with the 8 speed transmission that GM couldn’t fix. We had to hire an attorney and took about 7 months but GM bought the truck back and we bought a 2019 GMC Sierra Denali with the 6.2l and 10 speed transmission and can’t believe the difference. A completely different truck so smooth unbelievable. We are very happy with our truck now.

[DC Bruce]

I was aware that the 10-speed was developed as a j.v. With Ford. That doesn’t explain why. The 8-speed is a wide-range transmission. When not carrying a load, the transmission shifts out of First gear before you’ve cleared an intersection after a traffic signal turns green. In top gear, the engine is turning at 1500 rpm when you’re traveling at 65 mph. Having driven probably 60,000 miles pulling a FC 27 Airstream over all kinds of terrain, I never felt the need for another gear “between gears” to better match the engine with the load. So, I don’t see a strong need for another transmission that adds 2 more gear ratios to replace this one after — what — only 4 years. The 8-speed had “drive ability” issues from the outset. When coasting down to a stop or in very slow speed driving under light load, shift engagement was harsh, producing drive line shock. Multiple reflashes of the control software mitigated but did not eliminate this problem. Add that to my own and others’ experience with driveline shudder at highway speeds with low or fairly low mileage and my suspicion is the GM knew it had to develop a replacement PDQ. By contrast, Ford has been fitting a 6-speed in its trucks forever, so it’s easy to understand their interest in developing a 10-speed. The fact that GM still fits the 8-speed in some relatively low-volume vehicles (with less powerful engines) doesn’t seem to me like a strong endorsement of the transmission. I would advise buyers looking for a used GM half ton fitted with this transmission to be aware of the potential for problems.