Bucking while towing heavy trailer

[dieseldan723]

The best way to describe what I am experiencing while towing a 13K lb fifth wheel is a bucking sensation. It only seems to do it between 1-2 and 2-3. From 3rd gear on I don't notice it. This happens under normal acceleration. If I was holding a cup of coffee while this happens, I certainly would be wearing it!

With no load/trailer the truck seems to shift hard in those same gears, but there is no bucking sensation.

Is this normal? Any reason for concern?

TIA

 

[Billet Bee]

I ful time and towe a 13k fiver and have never experienced bucking in either my 16 2500 or my 20 3500 unless i go over a bad bridge expantion joint

 

[Firebird]

Definitely not normal

 

[14hemiexpress]

Probably a silly question but are you using tow haul? It sounds like you are trying to describe the shifting not suspension bounce is that accurate?

 

[dieseldan723]

Probably a silly question but are you using tow haul? It sounds like you are trying to describe the shifting not suspension bounce is that accurate?

Yes, I certainly use tow/haul mode. It's definitely the transmission and NOT suspension that is causing this feeling.

 

[14hemiexpress]

So the suspension is bouncing in the middle of shifts 1-2 2-3 but fine after? How new is your truck? Maybe shocks are shot?

 

[dieseldan723]

Sorry if I wasn't clear above. It is NOT the suspension, DEFINATELY the transmission. Truck is a 2020 (see signature) with 2,600 miles on it. It has performed this way since new. My first tow was around 700 miles.

 

[Timsdually]

How does it shift without Tow Haul when towing that trailer?

 

[14hemiexpress]

That was my bad I got that mixed up read it to fast. You can take your truck to the dealer and have them do a relearn on it/quick learn and see if that will clear it up.

 

[dieseldan723]

How does it shift without Tow Haul when towing that trailer?

I'll try that next time i tow, but I imagine it will be the same. Don't have a definitive answer because I never paid attention to that specific situation. I won't have the trailer for another few weeks when I get it back from the service dept.

 

[dieseldan723]

That was my bad I got that mixed up read it to fast. You can take your truck to the dealer and have them do a relearn on it/quick learn and see if that will clear it up.

I need to take it in for a couple other items so I will mention this to them. Thanks for the heads up.

 

[14hemiexpress]

I need to take it in for a couple other items so I will mention this to them. Thanks for the heads up.

A lot of these computer controlled transmissions can have issues cleared up by updates and relearns I hope it helps.