"jerking" at certain tow speeds

[Houndoc]

On Saturday I was hauling a horse trailer (3k pounds?) plus one horse (roughly 1,000 pounds) behind my Yukon XL (about an 8k tow rating). From about 40-45 mph, there would be a 'jerking' feel to the ride. Smoothed out at speeds above and below and overall trailered very well.

Without the horse in the trailer, the same thing would happen but at lower speeds (35-40).

Any ideas as to why and what to do about it?

 

[rolloverBill]

sounds to me that the trans is slipping right before shifting into overdrive. it'll probably get worse as the weather gets colder. I've been told that driving in O.D. (even not towing) when speeds are not over 40- 50 mph for a while (city driving) is not good on a trans. We have done this on our dakota and Olds intrigue. Each is at least 8 years old and 135,000 miles with no problems.And of course keeping it pink really helps. Good luck

 

[78mitsu]

could be a wheelbearing on the trailer. some trailers start to whip just a little at higher speeds and it exaggerates a loose or warn bearing. The 4l60 and 4l80 will set a powertrain code (P0894 or p1870) if they start to slip at any speed so you'll get a mil light if that were the case. Try pulling a different trailer, with about the same weight it'll localise it to the truck if it still happens.

 

[Houndoc]

I don't think it is the transmission slipping at all. The wheel bearing could be, or the other idea I have come up with is a tire issue on the trailer (balance, flat spot etc).

 

[NoRig]

Probably just that GM motor not being able to handle the load.

 

[ace]

Sounds like slack in the coupling between the trailer hitch and ball and the trailer is rocking front and back on the ballhitch. I feel this sometimes pulling double and triple trailers behind a Mac CH600 when the snubber on the pintle hitch isn't tight.

 

[rolloverBill]

I don't think it is the transmission slipping at all. The wheel bearing could be, or the other idea I have come up with is a tire issue on the trailer (balance, flat spot etc).

Test out your theory and hook up to another trailer.

 

[Houndoc]

I have towed a slightly lighter (perhaps 3k pounds) trailer with no issues. Nothing really makes me think it is the Yukon to blame. With the fact that it happens based on speed, not acceleration or deleleration, climb etc reminds me of a tire balance problem.

I will check the tires out carefully if/when I tow that trailer again (it was borrowed).

 

[Jay5.9L]

I was expecting a different topic going from the title LOL. Something along the lines of "On the way home from moab I was really bored and had the cruse control set at 65 mph......."

 

[tv_larsen]

If the trans TC was locked up it could be the lock-up clutch in the TC is starting to fail. I've seen it happen in Diesel autos, there's no reason it couldn't happen in a gasser. If that's it, it will only get worse.

If it happens again, and the TC is locked-up, don't change road speed and just downshift to see if it goes away.

 

[smashmetal]

I don't think it is the transmission slipping at all. The wheel bearing could be, or the other idea I have come up with is a tire issue on the trailer (balance, flat spot etc).

Bias ply tires on a trailer will do all sorts of weird things, especialy when there not ballanced. I ended up blowing out 3 of my four trailer tires in a 3 week period. Replaced them all with radials, had them balanced and know I can hardely tell it's behing the truck.

 

[Houndoc]

The problem is most certainly the trailer, and I would agree the tires, since other towing has not done the same thing.

 

[78mitsu]

The problem is most certainly the trailer, and I would agree the tires, since other towing has not done the same thing.

check the wheel bearings and carry a spare tire. Don't worry about it.