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