Truck bucking when stopping w bumper pull horse trailer

[Sig]

My ‘23 2500 bucks or oscillates up and down after I come to a complete stop with horses in the trailer. The truck settles back and starts an oscillation between the truck and the trailer that continues for almost 10 seconds as it dampens out. I have a Sundowner 2-horse straight load bumper pull. Dealership can’t figure it out and neither can the best trailer shop around me. Dealership also put the trailer behind a 3500 with air bags and it still happened. I have also tried a different brand of straight load bumper pull trailer and the same happened. It’s shaking the horses around every time I stop. Even just pulling forward 2 feet. Does anyone know how to fix this problem?

 

[tchur1]

Have you weighed the trailer and do you have sufficient tongue weight?

 

[Sig]

No I haven’t. But you really can’t shift the horses more forward. It’s a top horse trailer brand and I don’t have this problem towing with any non-Ram trucks. Even GMC 2500.

 

[Ramtop]

Do you have the hitch on the truck set up so that the trailer is fairly level front to back? Or at least the same as it is on the GMC?

 

[Sig]

Do you have the hitch on the truck set up so that the trailer is fairly level front to back? Or at least the same as it is on the GMC?

Yes, perfectly level.

 

[CdnHO]

Only way to be sure of any diagnosis is to weigh the loaded trailer. Then work from there. The ony other issue might be a bad magnet or wiring in the trailer brakes. Assume they are the standard electric drum brakes. As the magnets move the circuit breaks, and when the magnet returns to the original position the circuit makes again. Making the brakes apply and release continuously. Regardless, weigh the trailer first. Try stopping without the trailer plug connected.

 

[AH64ID]

Since it does it on multiple trucks I would suspect the trailer is the cause.

 

[Sig]

Only way to be sure of any diagnosis is to weigh the loaded trailer. Then work from there. The ony other issue might be a bad magnet or wiring in the trailer brakes. Assume they are the standard electric drum brakes. As the magnets move the circuit breaks, and when the magnet returns to the original position the circuit makes again. Making the brakes apply and release continuously. Regardless, weigh the trailer first. Try stopping without the trailer plug connected.

Thank you. I’ve tried with the trailer unplugged and also with a different but similar trailer made by a different brand. Featherlite and a sundowner. The trailer is about 7,000 lbs w 2 horses in it.

 

[Sig]

Since it does it on multiple trucks I would suspect the trailer is the cause.

I did as well and that is why I tried a different but similar trailer of a different brand. Both straight load 2-horse bumper pull trailers had the same result. One was a sundowner and the other was a featherlite.

 

[Rockcrawlindude]

Not enough tongue weight.

 

[AH64ID]

Not enough tongue weight.

I think so too. Our 4 horse stock trailer is so light on the tongue that I hate towing it empty as it constantly unloads the hitch weight with the slightest shift in road conditions.

 

[Sig]

Not enough tongue weight.

Do you mean for the truck or for the balance of the trailer? Do you mean I don’t have 10-15% on the tongue or is 700 lbs ish too light for this truck?

 

[AH64ID]

Do you mean for the truck or for the balance of the trailer? Do you mean I don’t have 10-15% on the tongue or is 700 lbs ish too light for this truck?

For the balance of the trailer. I suspect you're below 10%.

 

[Sig]

For the balance of the trailer. I suspect you're below 10%.

Thanks. I will check that next. However I don’t know how I would remedy that since the horses have a chest bar that prevents them from being loaded further forward.

 

[H3LZSN1P3R]

Thanks. I will check that next. However I don’t know how I would remedy that since the horses have a chest bar that prevents them from being loaded further forward.

Move the axle back

 

[Sig]

Could it be related to the coil suspension or how the brakes are adjusted? The GMC 2500 had leaf springs and it didn’t oscillate on that truck. Also, the trailer shop put the trailer on a different Ram 2500 w airbags and it was just about completely gone if he fully inflated his air bags.

 

[AH64ID]

Could it be related to the coil suspension or how the brakes are adjusted? The GMC 2500 had leaf springs and it didn’t oscillate on that truck. Also, the trailer shop put the trailer on a different Ram 2500 w airbags and it was just about completely gone if he fully inflated his air bags.

You said it still occurred on the Ram 3500…that has leaf springs.

 

[Sig]

You said it still occurred on the Ram 3500…that has leaf springs.

It did happen on the ram 3500. However, it had airbags, but not leaf springs. They were factory installed airbags.

 

[CdnHO]

It did happen on the ram 3500. However, it had airbags, but not leaf springs. They were factory installed airbags.

All 3500s have leaf springs out of the factory. Those with the air bag option don't have overload leaf springs, but do have the main leaf spring pack.

 

[Rockcrawlindude]

Could it be related to the coil suspension or how the brakes are adjusted? The GMC 2500 had leaf springs and it didn’t oscillate on that truck. Also, the trailer shop put the trailer on a different Ram 2500 w airbags and it was just about completely gone if he fully inflated his air bags.

No. The problem is not the truck.

Man, look. We can’t help you without knowing the weight of your setup. Without that we are just guessing.

Your trailer shop is completely incompetent if they are scratching their heads and haven’t weighed your setup. That’s the first step in solving the problem. Fully inflated airbags aren’t the answer on a (single axle?) two horse trailer.