New AT4X HD owner here.

[goatspeed]

Nice truck, welcome!

 

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[pinebaron]

In the past I have had an experience the vehicle manufacture will automatically cover an alignment within x miles of a new purchase in the even there is an issue. I can only assume your dealer would be glad to perfrom an alignment. Bummer for sure on a new truck, but hopefully that will remedy your issue.

I booked an appointment for 12/11 however I'm not sure if it will be covered under warranty at this time, I will call them to check.

 

[pinebaron]

Another thing I noticed and this may well be the way it is in these AT4X trucks, is the small gap between front lower arms and bump stops. There can't be that much room for down travel. What if the issue with a slightly bumpy road is the front lower arms constantly bumping against the bump stops. I could be completely wrong but thats how it looks to me. Can other owners of this truck please confirm the same. Further reading suggests these may be a jounce bumper designed to sit on the LCA and an integral part of the way the torsion bar suspension works; what do I know.

 

[WyomingAT4XAEV]

Hello, I also purchased the same truck in Diesel. Have you ridden the truck on freeways/highways? I seem to get a vibration all around if the road surface is undulating. I replaced all tires with just a few hundred miles on them and the problem did not go away. Can you confirm your ride is absolutely smooth or did you experience any vibrations at all.

My truck has zero vibrations. Tracks very straight on the highway. I bought it south of Salt Lake and drove it about 350 miles back home to Jackson, WY. I have also taken it on a couple mile hunting trip and no vibrations or tracking issues. Interestingly after picking it up at the dealership about 150 miles into my drive home I noticed the steering wheel is slightly out of vertical when I am driving straight. It is not due to the crown of the road or wind. I can let go of the steering wheel and it drives smooth and straight it is just probably 2 degrees counter clockwise from twelve oclock. I have been planning on taking it in to see if the dealer can just adjust it. Only problem is the nearest GM dealership is 100 miles away.

 

[WyomingAT4XAEV]

OP, I meant to post this sooner, but your truck is one GREAT looking truck. Congrats on owning such a great looking HD truck!

I don't live that far from you as the bird flies (I live in SW Montana). Love the vista in the background of your pics. That first pic from the front - damn your truck looks nice, and especially with that WY/MT vista!

I am interested in what kind of fuel MPG you are getting. What size tires/wheels? Any aftermarket lift?

Thanks! The tires and lift are from the factory. The size is 305/70 18". The only things I have added are swapped the antenna for a 6" rubber one. The stock one moves around a lot in the wind and I have added a Revolver X4S tonneau cover(really like it). On a couple hour trip Jackson, WY to Lander, WY including going over Togwotee Pass. The truck averaged 17 mpg. I would say in town it is probably between 11.5-13.5 mpg. Not as bad as I expected for a 8,500 lb truck with 35" tires and a 1.5" lift.

 

[WyomingAT4XAEV]

Another thing I noticed and this may well be the way it is in these AT4X trucks, is the small gap between front lower arms and bump stops. There can't be that much room for down travel. What if the issue with a slightly bumpy road is the front lower arms constantly bumping against the bump stops. I could be completely wrong but thats how it looks to me. Can other owners of this truck please confirm the same. Further reading suggests these may be a jounce bumper designed to sit on the LCA and an integral part of the way the torsion bar suspension works; what do I know.

Mine look the same as yours. Slight gap. I dont think this is what is causing your issue.

 

[pinebaron]

Mine look the same as yours. Slight gap. I dont think this is what is causing your issue.

Good to know. One thing out of the way. I'm repeating this statement I know, but the first 100 miles out of the dealership was a perfectly normal ride; then suddenly the bouncyness started and it just did not stop at any speed. Something must have happened when we were driving up the freeway. I do remember something I did probably a few minutes prior, on the freeway; I was driving around 60-75mph, traffic was sort of heavy and there was not much space for anyone to pass me on either side, one F-150 could have been a raptor or something kept tailgating me for quite a while, and I was somewhat nervous already with this new long truck. I remember at one point I saw an opening in the right lane, floored it to I think 95mph and sort of escaped the tailgater for a few minutes. Could that have caused something? Brand new truck subject to maximum power for a minute or two. I'm only guessing, did my act move or break an engine, gearbox or some mount, I have no idea. It was not long after that, we started experiencing the bouncy ride, which you just have to believe me, was a nightmare ride home, wife almost threw up and had a bag next to her face, yep it was an ordeal.

 

[WyomingAT4XAEV]

Good to know. One thing out of the way. I'm repeating this statement I know, but the first 100 miles out of the dealership was a perfectly normal ride; then suddenly the bouncyness started and it just did not stop at any speed. Something must have happened when we were driving up the freeway. I do remember something I did probably a few minutes prior, on the freeway; I was driving around 60-75mph, traffic was sort of heavy and there was not much space for anyone to pass me on either side, one F-150 could have been a raptor or something kept tailgating me for quite a while, and I was somewhat nervous already with this new long truck. I remember at one point I saw an opening in the right lane, floored it to I think 95mph and sort of escaped the tailgater for a few minutes. Could that have caused something? Brand new truck subject to maximum power for a minute or two. I'm only guessing, did my act move or break an engine, gearbox or some mount, I have no idea. It was not long after that, we started experiencing the bouncy ride, which you just have to believe me, was a nightmare ride home, wife almost threw up and had a bag next to her face, yep it was an ordeal.

That stinks. I am assuming that you did not hear a clunk or anything break when you floored it. I am new to diesel truck ownership as well and the torque this truck has is pretty amazing. I am thinking that something may have been tweaked like driveshaft or driveshaft mount, bushing that would cause an intense vibration at speed. Have you crawled underneath to take a look at the driveshaft and mounts to see if everything looks normal? Without hearing something break I am betting that something got bent or thrown out of whack. Especially since you have already replaced the tires and sounds like you are not noticing it at low speeds. Just my two cents. Could be totally wrong.

 

[pinebaron]

I have wheel alignment scheduled in a couple of weeks but I'm going to meet my local mechanic who has a lift and we are going to put it up there to take a look. I tried looking from below however with skid plates and all there is not much I can see at the front end. Perhaps when I get this up on the lift, we may remove the front skid plate and check engine, and other mounts, drive shaft play etc.
I do notice it at low speeds too, just more pronounced at higher speeds; I verified this yesterday.
Another thing I learnt from another forum where someone said the first thing they do with a new truck is to grease all zerks up front at least. But I think I need to be looking for something that just went out of whack while driving the first 100 miles.
Scheduled an appointment with my buddy mechanic for an hour of his time; I will have to pay for the hour

 

[pinebaron]

Yesterday, my mechanic drove with me and verified a rough stomach jarring ride on some paved highway roads. We returned to his shop and he greased all zerks around the front suspension, including one above the front skid plate, which, no surprise, had minimal grease.
In the meantime I also replaced side markers with smoked side markers; I think they look good. Front passenger side was easiest, followed by front driver side, then the rears install was somewhat painful but I got it done without damaging the vehicle.

I know this is an AT4 forum but can we start a "What did you do to your AT4X today' thread?

 

[nabatron]

Thanks! The tires and lift are from the factory. The size is 305/70 18". The only things I have added are swapped the antenna for a 6" rubber one. The stock one moves around a lot in the wind and I have added a Revolver X4S tonneau cover(really like it). On a couple hour trip Jackson, WY to Lander, WY including going over Togwotee Pass. The truck averaged 17 mpg. I would say in town it is probably between 11.5-13.5 mpg. Not as bad as I expected for a 8,500 lb truck with 35" tires and a 1.5" lift.

I’m getting terrible mpg in the city. 9-10mpg it’s pretty shocking to say the least lol. Have normal at4 on stock wheels with new Winter blizzaks.

 

[pinebaron]

I'd expect better milage on an AT4; our AT4X AEV is heavier with skid plates, steel bumpers and all. On my AT4X AEV I'm averaging 12-13.5 in town on Mickey Thomson Baja Boss AT 305/70R18 tires which I would also use for winter driving in the snow. Would have loved it but could not find Winter Blizzaks for the same size for my AEV SALTA wheels with 9" wide rims; what size wheels/tires are you using?

 

[nabatron]

I'd expect better milage on an AT4; our AT4X AEV is heavier with skid plates, steel bumpers and all. On my AT4X AEV I'm averaging 12-13.5 in town on Mickey Thomson Baja Boss AT 305/70R18 tires which I would also use for winter driving in the snow. Would have loved it but could not find Winter Blizzaks for the same size for my AEV SALTA wheels with 9" wide rims; what size wheels/tires are you using?

Just the stock 20s that came with the truck.

 

[pinebaron]

Just the stock 20s that came with the truck.

I see. I find tire pressures have significant bearing on mpg. While working on establishing bounce issue on my AEV, I dropped pressures to 45/42 F/R and mpg tanked.

 

[Bregea1]

Its good to hear your ride quality is so good which means theres hope for me. I'll see if I can fire up my old go pro 4 which I have not used in almost nine years.

I have the HD AT4X gasser. Had it for almost 2 months now, about 6k miles, mostly highway with a few trips on some northern Michigan trails. Absolutely no vibrations on the highway at any speeds. I do sometimes get a little whine noise that I haven’t figured out yet, but the ride itself is smooth.