Low speed pulsing <1mph

[masaidwakeupson]

When rolling at very low speeds <1mph there's a strange pulsing that rocks the car forward and back very rapidly. Like there's a jack hammer on the break pedal (not that severe). It's not the brakes or rotors, this happens when no brakes are applied at all. It's not the motor mounts or engine rocking. I've checked the engine bay with the car rolling.
I've tried manual mode and it occurs in 1st and 2nd gear. Pop it in neutral and roll to <1mph and nothing. I think it may be the trans. Which would be unfortunate as hyundai just replaced it under warranty a few months ago.
Is this a known issue?

 

[homeofstone]

I think you may be correct in that its the transmission. Which I think is good because it will be under warranty.

 

[srobak]

Driveshaft lash. Normal, especially on RWD cars at that speed. Push the gas pedal.

 

[landtuna]

Driveshaft lash. Normal, especially on RWD cars at that speed. Push the gas pedal.

I would agree but only if it is a manual. An automatic trans should take up the slack at those very slow speeds and the owner's description of "jack hammer" pulsing makes me think it is not a normal condition.

I would get it into the dealer shop ASAP and have them check it out while the symptom is repeatable.

 

[masaidwakeupson]

Driveshaft lash. Normal, especially on RWD cars at that speed. Push the gas pedal.

I don't believe it's normal for the car. I've been driving the car for nearly a year with 2 separate transmissions and this issue just started happening.
I have noticed it gets worse once the motor/tranny gets warm.
It's not a violent rocking back and forth but it is very noticeable.

I'm just gonna drop it off at the dealer when I have the time and see what's what.