Fifth wheel Jerking with gas truck... not as noticeable

[Part-Timer]

Hello all. First time poster long time lurker. I have been visiting this forum for years. You all are a wealth of information and knowledge. I appreciate all of the expertise on here and you have helped me tremendously over the last decade or so of RVing.I felt the need to create an account and post since I tried searching this forum and many others for an answer but have yet to be able to find one.

Long story short. I have a 2021 chaparral 298rls 5th wheel and a 2024 silverado 3500 gas with 10-speed allison. I have the factory gm puck system and factory curt hitch mounted in the bed holes. My rv tends to "jerk" almost like a fish biting on a line feeling but only when accelerating. Sometimes it is much more noticeable than others... it's hard to describe the feeling, it is NOT chucking like you feel when hitting expansion joints or bumps. It is almost as if the brakes are pulsing 5-6 times a second like a quick "tug - tug - tug - tug -tug" feeling. Sometimes enough to jerk the truck and occupants, sometimes more of just a feeling in the wheel, seat, and gas pedal.

This happened on my old 2022 gas 2500 truck with the same trailer and hitch. Mainly under harder acceleration between 2800-3700 rpms then goes went away after 3700 rpm or so...

I took it to the dealership and they replaced the torque converter and when that didn't fix it, they replaced the transmission pump as one of the fins on the pump had a crack after inspection. That didn't fix it either. A new transmission was on backorder at the time so I decided to trade the truck for a diesel as it was all that they had at the moment. New truck was a duramax and 10-speed allison.

The diesel occaisionally did the same thing but not nearly as noticeable... mainly just slow accelleration in stop and go traffic. But this at least let me know that it was the trailer in some way doing it and not the truck. I learned to live with it and pulled for another 5000 miles or so with 3 different diesel HD silverados all 10-speed allisons.

Fast forward to today. I traded my last diesel for a new 2024 gas 6.6 with the 10-speed allison as I really don't need a diesel for my uses. (Trailer is roughly 12,000 lbs loaded)

Figured the new allison like the diesels would feel the same, but almost immediately I noticed the jerking again under acceleration. Much more prominent with the gas trucks than with the diesel trucks.

Starting with the original gas truck I tried all kinds of trouble shooting from hitch adjustment, pin box adjustments, adding timbren ses to lessen rear sag, different tire pressures in the rear tires, filling my truck bed with hundreds of pounds of tools, filling the water tanks, emptying the water tanks etc..


Now that I'm back in gas truck I am noticing it again and it's much more prominent than in the diesel trucks. IDK if that's due to the additional weight of the diesel engine over the front axle or possibly just the additional mass lessening the "felt" tugging.

We also just replaced all the factory china bomb tires with Goodyear endurance tires after another costly blowout and still feels the same. So that rules out the trailer tires which was my last guess.

Has anyone experienced this before or have any insight? Again, it is not chucking like when you hit an expansion joint. The road can be perfectly smooth and as you start to accelerate or "pull" the trailer at more than just a leisurely pace, it'll start "tugging" 5-6 times a second. This goes away after 3800 rpm or so all the way to 5000 rpm.

With the timbren SES the trucks sits almost level, the rear is still about an inch higher than the front. My old truck had this issue both before and after the timbrens so I know it's not the angle or rake of the truck.

Any insight would be greatly appreaciated.

[soneill5]

Cummins12V98 wrote:
They are still having issues. Look at the youtube video "Why We Ditched The Andersen Hitch".

I did s simple search "Andersen Ultimate 2 hitch failures".

In all fairness, the video above could be considered an extreme circumstance. The trailer was hit while driving and went into a fish tale, but didn't fail, nor lose the trailer. I would question any hitch after that - especially one connected to the goose ball.

[Cptnvideo]

Just curious. Have there been any documented hitch failures for the Hensley TrailerSaver BD series?

[TravelinDog]

Cummins12V98 wrote:
They are still having issues. Look at the youtube video "Why We Ditched The Andersen Hitch".

I did s simple search "Andersen Ultimate 2 hitch failures".

There are just as many "why we love the Anderson hitch" articles out there as well.
Most people simply hate the Anderson hitch because of stuff they read on the internet which is ALWAYS overblown and exaggerated.
Almost none of their reasons come from first-hand knowledge, just hearsay.

ANDERSEN HITCH FAILURE RATE
It’s impossible to determine the exact failure rate of Andersen hitches as the majority are only minor and go unreported. Most drivers deal with the hitch failure themselves without reporting it or taking Andersen to court. There have been no major court cases involving damages caused by an Andersen failure.

[Part-Timer]

"I had a similar issue but with a Ford, actually a couple of Fords (all LB CC DRW) It was finally determined to be just that driveline shudder / driveline wrap, most likely due to the carrier bearing being "soft" and allowing the driveline to whip around, as CC, LB has a long driveline.
Were all your trucks the same? CC/LB..ETC?
Do you know any Ford or Dodge owners? Perhaps a test tow with a non GM is in order."

They have all been crew cabs but both long and standard beds. Though it could be the driveline in all of them. Unfortunately I don't have any friends with hitches on their trucks that I could test out.

I've read a good bit on the issue and know that some ford diesels had a similar issue due to accelerator pedal input or something similar. I thought it may have been that issue since they're all drive by wire now but it does it even when using cruise control which elliminates the possibility of my foot bouncing on the throttle.

[Cummins12V98]

They are still having issues. Look at the youtube video "Why We Ditched The Andersen Hitch".

I did s simple search "Andersen Ultimate 2 hitch failures".

[cummins2014]

Cummins12V98 wrote:

cummins2014 wrote:

Cummins12V98 wrote:
EASY!!!

It's your CURT hitch. Look at how low the pivot point is on the CURT. FACT it can cause a chucking feeling.

Compare to the B&W that has it's pivot point at the height of the kingpin.

What took you so long . It's sure possible it's the hitch . He is a great candidate for the Andersen , and IMO would solve his problem . I am sure you will agree on the Andersen with the weight he has , no need for some expensive hitch .

If they made it to attach to the pucks instead of relying on thin beds to support the fore and aft and make the tubing stronger I would consider it for a 12 RV.

YES the CURT can cause a chucking sensation that's a fact.

You do realize they redesigned the Andersen after the problem with what a couple bent hitches ,and since we have had no reports of bent tubing . And as you know shimming the valley on the bed cures that problem . My son runs the Andersen with a bit heavier fifth wheel than the OP ,and there has been no bed deflection . I do believe they have changed the base a bit also .

To be fair ,there has been hitch failures across the board ,so to single out the Andersen is a bit unfair . Also there has never been a fifth wheel come undone with an Andersen . On the other hand how many fifth wheels have dropped on the bed of a truck with every conventional hitch made . Impossible to drop a fifth wheel on the bed of a truck with the Andersen .

[Nv_Guy]

Krusty wrote:
Sounds like it could also be a driveline shudder. Some trucks are more prone to it than others, depending on driveline type, wheelbase etc. They are fine at normal ride height until a load is applied and it changes the u-joint angles enough to create a shudder felt on accel from a stop.

I had a similar issue but with a Ford, actually a couple of Fords (all LB CC DRW) It was finally determined to be just that driveline shudder / driveline wrap, most likely due to the carrier bearing being "soft" and allowing the driveline to whip around, as CC, LB has a long driveline.
Were all your trucks the same? CC/LB..ETC?
Do you know any Ford or Dodge owners? Perhaps a test tow with a non GM is in order.

[Cummins12V98]

cummins2014 wrote:

Cummins12V98 wrote:
EASY!!!

It's your CURT hitch. Look at how low the pivot point is on the CURT. FACT it can cause a chucking feeling.

Compare to the B&W that has it's pivot point at the height of the kingpin.

What took you so long . It's sure possible it's the hitch . He is a great candidate for the Andersen , and IMO would solve his problem . I am sure you will agree on the Andersen with the weight he has , no need for some expensive hitch .

If they made it to attach to the pucks instead of relying on thin beds to support the fore and aft and make the tubing stronger I would consider it for a 12 RV.

YES the CURT can cause a chucking sensation that's a fact.

[Part-Timer]

We're pulling the trailer to Myrtle beach next week and this will give me an opportunity to test some of the suggestions on here. Will report back.

Maybe I can talk the wife into a new hitch to see if that helps


thanks

[Part-Timer]

Just to give as much info as possible here. The same hitch has been used on 4 trucks, two diesels with the 10-speed allison and two gas HD's one with the 6-speed and the current one with the 10-speed allison.

3 of the trucks had the factory puck system, one I installed bed rails and bought new legs for the hitch but used the same head.

Truck # 1 was a gas engine 6-speed 2500 hd crew cab short bed 4x4 with factory puck system. Installed timbrens to correct any driveline angle issues. Had a new torque converter installed as well as transmission pump. Assuming it was the truck... I traded for truck number 2.

Truck # 2 was a duramax/allison crew cab short bed 4x4 with bed rails but same hitch head with new legs.

Truck # 3 was a duramax/allison 3500hd crew cab long bed SRW 4x4 with factory puck system and reused original legs on original hitch.

Truck # 4 is a gas/allison 3500 SRW short bed crew 4x4 with factory puck system same hitch and legs. When I installed the hitch in this truck I made sure all bolts were tight and have the feet/cleats locked to the bed tighter than I ever have. (this elliminated any slop in the hitch when starting or braking and I have zero "clunking" slop.

My first thought was driveline shudder which is why I have installed timbren SES on all of the trucks and the "tugging" is there with our without them so I've pretty much ruled out driveline shudder since the timbrens keep the truck pretty high in the rear. But I enjoy the stability they provide so I've kept them on each truck.

I know 4 trucks is a lot in a couple years... And no, I'm not wealthy but I work at a chevrolet dealer so I've been able to play my cards right in regard to the flucuating market and trade values. I have been fortunate enough to be able to trade often without really costing me any real money.

The trailer brakes seem to function as they should and there's nothing I can see that would indicate a worn or out of shape drum, though the drums and bearings are about the onluy thing I haven't pulled apart.

I just had all four wheels off when installing new tires and all were retorqued. Again, same tugging as before with the old tires.

The unit has the "road armor" suspension. Possibly the axles are bouncing or hopping when being pulled at certain frequencies?


I'm honestly boggled. I've learned to live with it but assume something is causing it and may have bigger consequences later on down the line if I can't address it.

[hondapro]

Cummins12V98 wrote:
EASY!!!

It's your CURT hitch. Look at how low the pivot point is on the CURT. FACT it can cause a chucking feeling.

Compare to the B&W that has it's pivot point at the height of the kingpin.

I agree, the hitch is the common part that has been used with both trucks.

[GaryUT]

I would check for a mechanical problem with the trailer. bearings , out of round brake drum, wheel not concentric to the hub.

[cummins2014]

Part-Timer wrote:
I have entertained the idea of the Andersen goosneck adapter. Hard to convince the wife of the cost when I have a "perfectly-good" hitch now. I like the convenience idea of the Andersen and the light weight in/out removal concept especially compared to the 200lbs of cast iron that I have to deal with now. But I'd hate to spend the money just to have the same jerking that I'm feeling now. As for normal "chucking" common to fifth wheels... I really don't have any to speak of. It really does pull and track well and the handling is great. Just this tugging sensation when accelerating at certain rpms is mind boggling.

You do have a usual situation. Maybe so , spending $700-800 to hopefully solve the problem. But those Curt hitches has caused some towing issues .I know we can get some driveline shudder on a hard acceleration with a heavy fifth wheel, as mentioned . What would be ideal is switching hitches with someone to eliminate the hitch . Apparently not the truck , so that leaves the fifth wheel is causing an issue . Or maybe a friend with a fifth wheel you can test things .

[Krusty]

Sounds like it could also be a driveline shudder. Some trucks are more prone to it than others, depending on driveline type, wheelbase etc. They are fine at normal ride height until a load is applied and it changes the u-joint angles enough to create a shudder felt on accel from a stop.