MAJOR issues with 2011 Chevy 3500HD dually towing G/N, ideas?

[GOOSE]

I am working for a contractor who has triple axle enclosed gooseneck trailers, about 18,000lb curb weight, doesn't seem unbalanced. I towed one yesterday with their 2011 duramax dually 4x4 and was warned of a situation where it bucks when applying the brakes. To make matters worse I quickly found out that the electric brakes were not working.

I hit the brakes gently for the first time and the truck began this VIOLENT bucking and shaking. This proceeded all the way to a stop. I let off and rd applied the brakes several times but the bucking continued. Its BAD, to the point that I think you could do permanant damage to the frame of the truck and possibly the trailer in short order. The problem subsided a bit when you used the engine brake, downshifted manually, and then applied the brakes.

I feels like the frame is arching and then releasing like a bow and arrow would. They put air bags on the truck and said that cured the problem but it obviously did not. I am fixing the trailer brakes today and am anxious to see an improvement. It is however very disturbing to know that characteristic could return if the trailer brakes fail. One worker thinks that a small bit of slop in the g/n could be causing this, any ideas?

I am very tempted to put a g/n in my truck and tow this trailer to see if the problem is replicated on another truck. Any input is greatly appreciated. ORson grammar and spelling, I'm on my phone.

 

[Ruger_556]

Something isn't right... Out of round drums (Is it drum or 4-wheel disk?). Possible loose suspension components?

 

[towcat]

something is very wrong here. 18k GN is not beyond the capability of this chassis. the older 19.5" wheel HD3500 chassis did have a problem with warping rotors. never experienced warped rotors on the back of the truck, but if you had it in the front, the outcome would be a bad case of deathwobble until you came to a complete stop. i suspect you have a problem with the rear axle of the truck or the ABS is trying to compensate. easiest test is to unplug the abs computer and go on a test drive. report on results. second, check out the rear axle, look for rusty streaks, that will indicate loose connections.
report back!

 

[tanman_2006]

I'd check pin weight and balance. Maybe try and adjust the hitch (up or down) if possible. Put the truck on another trailer to rule out the truck. Check the trailer frame for busted welds allowing the trailer to flex and bow.

I had a 32ft gooseneck start bucking behind my 93 and it was busted welds on the subframe that the trailer suspension bolts to.

 

[GOOSE]

The shop supervisor told me that the truck didnt have this issue with the trailer I was using, he was wrong about that one! they swapped trailers with trucks already, the other truck is an 07 Chevy spec'ed the same as the 2011. The trailer is easy to look at, in the shop now. I will try to look the truck over tomorrow and get back with more info. Just a note, the truck handles well and no brake issues empty.

 

[GOOSE]

I was really trying to like this Chevy but it posted 2 strikes against it in 2days. Day 1 was the bucking incidents, today I repaired the trailer harness to lose functions in the bed 7 pin socket and lost the tail lights in the bumper socket. I looked underneath the bumper to find like a hundred wires and twenty plugs and who knows what they plug into up high over top of the spare tire area. The fuses check good. A local Hecht trailer dealer did the work (adding the 7 pin socket in the bed) so they will be fixing this as per the shop supervisor. Hecht claimed to have fixes the bucking by adding air bags, I am still going to look that over, I want to get to the bottom of that one.

 

[towcat]

sounds more like the fault of the installer rather than the fault of the product.

 

[tanman_2006]

Yeah, ALL newer trucks have a gazillion wires. The installer might have ran their own separate harness in addition to the OEM GM harness (my bale beds are like that).

There arent that many things that can cause a truck to buck like that and not cause issues driving w/o load.

 

[GOOSE]

I have been digging for information from those who drive these rigs the most. I am new here and haven't driven these a whole lot. I have found that any combination of the two trucks and two trailers can yeild this bucking problem. I hope to video an incident to see what is really going on. My gut feeling is that the g/n section of the two trailers isn't built heavy enough and this is where the flex that causes the bucking is generated.

 

[tanman_2006]

I have been digging for information from those who drive these rigs the most. I am new here and haven't driven these a whole lot. I have found that any combination of the two trucks and two trailers can yeild this bucking problem. I hope to video an incident to see what is really going on. My gut feeling is that the g/n section of the two trailers isn't built heavy enough and this is where the flex that causes the bucking is generated.

This is my bet. I've seen light built trailers cause alot of issues with handling.

Source Unknown

 

[asmith]

bump! Did you ever figure this out? the suspense is killing me!:

 

[GOOSE]

I have concluded that its the way the trailer is built and adjusting the brakes is very important.

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[GOOSE]

There is no way that the issues I have encountered are truck related.

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[asmith]

so you think that the trailer is too lightly built in certain areas like was theorized above? now that the breaks are adjusted better has it improved some?

 

[GOOSE]

I tend to adjust the trailer brakes light. I don't like it when you're going real slow and the trailers brakes are dragging heavy. Giving the trailer brakes some more authority has greatly reduced the bucking tendency that I encountered early on.

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