Another JR

My neighbor confirmed the dealer told him the second event was due to the transfer case suddenly shifting into 4 low. They do not know why it occurred. They also found some collateral damage to the transmission and repaired that. I would have thought they’d replace every part having to do with transfer case control, but apparently they didn’t. He’s hoping for the best but if it happens again it will be a clear lemon law case under WA law and I suspect he’ll have them take it back.

I’ll keep an eye out for my neighbor and ask him

I crawled under and looked on both sides of the transmission and did not see anything like that. I could not get a view of the top of the transmission.

I’m not sure I can see the breather hose in your photo, but generally the breather hoses for driveline components are routed to a high location to keep water out if someone drives into deep water. The rear axle breather hose, for example, is routed to behind the fuel filler location. I would think they would try keep the hoses away from the exhaust side of the driveline to avoid heat damage to the hose or coking. If it is a transmission or transfer case breather hose, I wonder if what you are looking at is the transmission or transfer case end of the hose that has become disconnected from the case vent. I’d get a mirror and light and locate the vent hose connections on the cases and make sure the hose is still connected. I can look at mine tonight if you still need a comparison at the end of the day. 2021 3500 hd cclb srw gas.

I don’t think I’ve felt vibration like that. I definitely do not have the boom sounds you describe. Mine is a 2021.

I’ve had the camper back on for a month now and just got back from a long highway trip. (My loaded pop-up slide in camper puts 100 lbs on the front axle and 1700 lbs on the rear axle.). The difference going back to the base torsion springs when driving at highway speeds is very noticeable when going over bumps and dips. The suspensions response is well matched front to rear now, and the truck does not pitch nose up when hitting dips and bumps. After this trip I’m definitely glad I made the change. The suspension feels “right” now. I highly recommend that, if someone bought the snowplow suspension but isn’t going to install a plow and isn’t putting a very heavy load on the front suspension, they should consider installing the base front springs in their truck. It took me 2 hours and $570 to change them.

I’m curious why you are running such large wires to the camper. Dedicated second alternator?

My 21 3500hd gas does not do that. I stop filling at the first shutoff. Maybe you have a kinked fueling or vent hose? The hoses are very easy to inspect, but why not ask the dealer to look at it?

If you have a diesel then your batteries are wired in parallel with no isolator. You are correct that the two batteries are required for sufficient starting current. I have not looked at the battery fuse blocks on a diesel, but my guess is the 500 amp fuse is the main connection between the two batteries. Just a guess, though.

I would list out the load combinations (cab contents plus bed contents plus trailer tongue/pin load) you want to be able to haul, and realistically estimate the payload weights with some margin added (maybe 500 lbs). If all those numbers are around 3000 lbs or below, a 2500 should be fine and will have a better ride when empty. If any of those total payload numbers are above 3000 lbs, then you need to look at the expected truck payload capability and make a careful decision. If any loads are above 3500 lbs, you probably need to go with a 3500. For me, at the time I ordered the truck I wanted to keep my options open to grow into a hard sided 9 foot camper like an Arctic Fox if I decided to go there. With that plus towing a boat the answer was clear. Now that I’ve had my 1800 lb FWC pop up camper for a year, I now know I will never get a hard sided camper. If I was reordering now I’d go 2500 for the better ride. However, at the time, 3500 was the right decision, and I’ll live with it. I still really like the truck, and I know at some point I’ll fill the bed with firewood or a water tank and be glad I have the one ton with its over 4000 lbs payload. I can also set up my boat trailer with a heavy tongue load if I want even with the camper on. If you plan to drive a lot unloaded it’s worth looking at this carefully rather than just defaulting to the greater payload of the 3500 because of the ride difference.

Heres the sticker for my 2021 3500hd SLT cc lb srw gas truck. Payload is 4,054 lbs.

Sounds to me like you made an excellent choice for your towing needs and your ride comfort. Your payload is still going to be in the 3000 lbs ballpark in a 2500. This coming from a 2021 3500 owner.

I have towed 5 to 8 k trailers with my 1/2 ton Yukon XL, my 93 K2500 truck, and my 21 3500hd gas. Increased weight of the tow vehicle, stiffer suspension and tires, longer wheelbase, and bigger brakes all contribute to better control of a large load. Your ‘feel’ about the heavier duty truck being safer comes from all of these things, and is accurate. I have a neighbor who has only ever driven half tons and he keeps spouting specs at me, and I keep telling him to go drive an hd truck. There’s no convincing some people to even try a different thing.

MTU - Thanks as always for providing correct information. I misunderstood the design differences in the spring pack. I could swear I read/saw something somewhere that said the rear axle was different, but I just tracked down the video I looked at and saw that it’s 4 years old, so it must have been for the previous generation of hd trucks. Thanks for your patience, contributions and polite corrections. I deleted my incorrect statements in the above post.

I have a 2021 3500 hd srw cclb slt. Most of the time I have an 1800 lb pop up slide-in camper installed, which puts 1700 lbs on the rear axle (I weighed it). I bought the 3500 because I wanted to be able to tow an 8000 lb boat trailer with the camper installed. Disadvantages of a 3500 relative to a 2500: 1) You have no choice in mirrors. The huge towing mirrors are it. They are nice when you are backing up, but block visibility the rest of the time. It’s the most significant thing I don’t like about my truck. 2) At bed loads from about 1500 to 3000 lbs, the rear overload springs are in contact part of the time, and you hear clunking as you go over bumps and dips each time the overloads hit the bumpers. The overloads statically begin to contact the bumpers on my truck at a bit above 2500 lbs of added rear axle load. In this 1500 to 3000 weight range you don’t need the overloads, so if the 2500 can meet your payload needs you might want to avoid this. 3) In some states registering a 3500 will cost you more unless you buy a derate option. In other states, like WA where I live, the 3500 cost about $500 or $600 less to register yearly than a 2500 would have cost. So you have to research that for your state. 4) Tire pressure warning on the rear is set higher on the 3500, so you are limited in how low you can run the rear tires to 62 psi, which is too high for best ride when running empty. There are some advantages to the 3500. Payload is the obvious one.

All of the above is correct. It also does not have auto stop/start. Here is a web page with information about the engine: https://gmauthority.com/blog/gm/gm-engines/l8t/

It’s interesting how different the approaches of the states are. In WA, a newer 2500hd yearly registration is probably well over 500, but my 2021 3500hd renewal a month ago was only $110.

I should have quoted you above so you’d get notification of the response.

I recently posted a detailed thread in the mod forum on the torsion spring swap in case you are interested. The new front springs are $200 to 220 each on line, but shipping is a bit over $100 for two. The price was comparable ordered from my local dealer’s part department, and it was more convenient for me to pick them up from the dealer. I saved forum member MTU’s table of spring part numbers and had my dealer verify it before I ordered. I can post the table again if you need it. The swap took me 2.5 hours, but I had not jacked the truck up previously and a bunch of that time was spent figuring out how I wanted to jack and support it. I could do the job again in less than 90 minutes. Unlike the older trucks, the spring ends have a looser fit and won’t be stuck in place. Mine came right out. Adjusting the torsion keys doesn’t change the spring rate or ride stiffness - it just changes the front suspension height. I set mine to the exact same height as the original springs.

Same neighbor told me two weeks ago he had it happen a second time after the first repair. He was able to limp it home several miles, but in 4 low because it would not come out of 4 low. He was talking about pursuing a buy back. I saw yesterday he had it back, but I haven’t had a chance to ask him what was done by the dealer. It seems to have proved that the sudden lockup is caused by the transfer case shifting to 4 low though for some reason.

Pardon the thread drift here: I can’t answer your question about intellihaul, but I noted your comment about preferring cloth seats. I like cloth seats as well, but when I was making decisions when ordering my 2021 GMC 3500hd I found the lower seat trims very uncomfortable, and was forced into leather bucket seats to get seats that were comfortable for me. The seats themselves - not just the upholstery - are different with the different configurations. Make sure you actually sit in what you plan to order before you decide. Good luck with all the decisions.

I can’t tell for sure because your camera focused on your hand and the connector is out of focus, but that second picture appears to be a FAKRA camera connector. The camera connection is not in that big oval multipin connector. It’s a dedicated coax connector. My truck is a 2021 3500 slt with surround view cameras so it should be the same.

First hit on duck duck go: https://static.nhtsa.gov/odi/tsbs/2021/MC-10207911-9999.pdf

I’m very happy with my 2021 3500hd gas truck as well. It’s smooth, quiet, doesn’t stink, doesn’t care about short trips, has plenty of power for my needs (carrying a light slide in camper and towing 8k), and just goes with no problems so far at 1 year and 5k miles. The 6 speed transmission is very well matched to the engine and works great. I do not wish i had a 10 speed. The SLT leather interior is great. The truck cost 65k out the door with 10% sales tax.