Shuddering while under light acceleration in any gear

Hi,

My truck, a 2007 5.7 with 160k miles, very suddenly started having this problem a few weeks ago.

It shudders under light acceleration. The vibration can feel pretty intense at times and can be very noisy. Other times it's not noticeable at all. It seems to shudder in any gear. The shudder stops when put in neutral / coasting or when the throttle is feathered in gear so that there's no load on the drivetrain. It seems most apparent around 50mph but it was also doing it at 5-10mph yesterday, so I dunno. It does not seem to shudder under strong acceleration and I haven't noticed any drop in torque, but I can't be sure of that.

I'm bringing the truck to a mechanic on the weekend but am looking for some additional advice before I go. Probably unrelated, but it has been having some 4wd actuator issues in recent months, with some struggle to get it into and out of 4HI but unless anyone feels otherwise, I don't think the 4wd actuator issue is related to the shudder, and I'd like to focus on the shudder problem and will treat the actuator separately if the truck survives the mechanic...

It is absolutely not a wheel balance issue, and probably not an engine mount issue. There is something going on in the drivetrain. I'm very concerned this may be a torque converter failure which will probably result in a trip to the car crusher due to the cost of the repair.

Any feedback would be greatly appreciated, I need a reliable truck that doesn't cost $100,000 and my hand is on the nuke button at the moment..

 

Have you done this in 4WD and 2WD? Find a long stretch of really good road, no semi wheel ruts etc. test it back and forth. Then do it again but use the manual shift. Start in low, 2 - 3 - 4 - 5 all in manual mode and both 4 & 2. This will isolate any front end stuff right away if nothing in 4 wd. Have you ever had the transmission serviced? Simple fluid change isn’t a service.
But my first ideas is universal joints. I’m assuming nothing in steering wheel? At any speed?
These are so heavy duty my second idea is the expensive one but possible transmission issue.
Hope this helps. I’ll monitor since I have a 2007 RCLB SR5 2WD. I developed a slight shudder but
it was after I installed SOS lowering kit and SOS airbag kit. Mine is really light and I think the kit
changed the pinion angle just enough. Mine is second driver and light duty so I’m not chasing it yet.
But anything you find out I’d be appreciative to hear.

 

In case anyone was wondering, it was a U joint. The previous owner had replaced all U joints except the one that failed, and the one that failed resulted in the above weird symptoms. Once replaced all was well again in the drive train. The 4x4 actuator issue is still an issue but it is clearly unrelated to the U joint problem.