Shudder/jerking/axle wind up

[Bearskinrug]

New owner of a 4/2024 built wagon equipped with rough pack. About 1100 miles so far. Love the truck.
At about 990 miles started experiencing some jerking/shuddering at various forward speeds, most reliably 30-50mph in 4-6th gear. No associated noise. Thought it might be axle wind up and so did some reverse driving with steering left/right and it may be a little better but not resolved. The feeling reminds me of when I learned to drive a manual and struggled to match the clutch and gas, but more subtle.

Anyone have this issue or have any ideas? Thanks for the help!

 

[AaronS]

Why would you suspect axle wind up? Is the center diff locked?

 

[Bearskinrug]

Well the symptoms seem to fit most closely with that diagnosis after google search. I’m open to other possibilities of course.
I cycled through high and low diff lock and locked/unlocked front and rear diffs on some sloppy gravel road after the symptoms started and there was no change.
I’d love to solve it without dealer help since the closest is 300 miles from me but I also love the truck and want it to last.

 

[AaronS]

Unlikely that it is axle windup as that would not be speed/gear related. Easy to check though... Block a couple of the wheels to prevent the truck from rolling, put it in neutral and ebrake off, jack up one wheel until it is off the ground. If it "unwinds" tension from the drivetrain, then you may have the correct diagnosis.

 

[AaronS]

When did you last refuel? Is bad gas a possible culprit?

You mention the symptoms occurring in three different gears (3,4,5) and within a 20mph speed range... is it only when in 3-5 gears between 30-50mph? What happens if you manually change gears without changing speed? What happens if you change speed but hold the gear? Do symptoms stay or go away?

 

[LeeroyJ]

Transfer case shifter is in the top left position, correct?

 

[Bearskinrug]

Thanks for the great suggestions all.
Yes T case lever is in left upper position.
I thought bad gas too, used a gas station I don’t normally use recently but have topped up a couple times at Costco which I think would have highest turnover of high octane in my area. Not outside the realm of possibility though.
I’ll try manual shifting in the way home tonight and see if I can lift a wheel this week.

 

[HereinDaRockies]

> jerking/shuddering at various forward speeds, most reliably 30-50mph in 4-6th gear.

Not enough detail in your description.

Are you coasting or applying throttle, when this occurs? What rpm?

 

[Bearskinrug]

> jerking/shuddering at various forward speeds, most reliably 30-50mph in 4-6th gear.

Not enough detail in your description.

Are you coasting or applying throttle, when this occurs? What rpm?

Yes constant throttle. Not sure about rpm but I’d guess 2k-3k. I’m not an aggressive driver and am still in the break-in period so I’ve been taking it very easy. I do think the Symptoms are less noticeable with heavy throttle however.

 

[Bearskinrug]

When did you last refuel? Is bad gas a possible culprit?

You mention the symptoms occurring in three different gears (3,4,5) and within a 20mph speed range... is it only when in 3-5 gears between 30-50mph? What happens if you manually change gears without changing speed? What happens if you change speed but hold the gear? Do symptoms stay or go away?

Manual shift on the way home, went through all 8 gears, no symptoms at all in manual mode anll the way up and coasting back down to a stop. Also, A lot of fun, searched for the clutch more than once.

 

[NQ94]

Take to some one that can check the transmission oil level and colour. Auto transmissions can shudder if there is low oil or it's contaminated. Could be as simple as a trans reset for it to relearn.

 

[AaronS]

Manual shift on the way home, went through all 8 gears, no symptoms at all in manual mode anll the way up and coasting back down to a stop. Also, A lot of fun, searched for the clutch more than once.

Ok... so... in drive create the conditions and the symptoms. Then move the level to M without changing other things. Symptoms stay or disappear?

 

[NQ94]

Ok... so... in drive create the conditions and the symptoms. Then move the level to M without changing other things. Symptoms stay or disappear?

My thinking in manual mode the line pressure would be higher and clutch fill times would be quicker and lock up holding masking a fluid fault. In normal driving with part throttle the transmission would be modulated more towards a nice shift so lower line pressure slower shifts, and possibly the lockup has a momentary slip during the shift to give a pleasant drive experience. Shuddering can be associated with TCC lock up faults.

 

[AaronS]

My thinking in manual mode the line pressure would be higher and clutch fill times would be quicker and lock up holding masking a fluid fault. In normal driving with part throttle the transmission would be modulated more towards a nice shift so lower line pressure slower shifts, and possibly the lockup has a momentary slip during the shift to give a pleasant drive experience. Shuddering can be associated with TCC lock up faults.

Absolutely a good idea.

 

[Bearskinrug]

This sounds like a dealer level problem?
Anyone check the transmission fluid on their own yet?
Truck was born 4/2024 and I bought the truck 6/2025 new so it sat a lot. Have been wondering if that would lead to issues down the road, but the transmission fluid should be clean at least. Although when I picked it up it needed an alignment before I left the dealer as it pulled pretty hard to the left, I guess from the factory….
Have no warning lights or errors. T case temp max around 145F and gear box around 176F on long drives.

 

[Gasguzzler]

I would say you are going to have to get it checked out at the dealer. I have never experienced that. In heavy traffic from 1st to 2nd and back down sometimes it will clunk, but that is normal...