Bang or Thump in TC or Tranny

[Jaxom]

I've recently started feeling a Bang or Thump in the driveline. It ranges from severe to barely felt it. Only when towing. Tried in Tow/Haul, OD lock out and regular...Best in OD lock out, then T/H then regular Drive.
It started about 1 month ago, before I got the Smarty Jr. Seems to get worse as the trans warms up and at higher highway speeds.
Trailer weights range from 16,000 5th wheel to 3,000 aluminum flatbed. Much worse w/ the 5th wheel.
Tachometer does NOT move or jump when this banging occurs.
Tranny does not slip. At least you can't feel it and no RPM change.
No other symptoms.
Trans fluid, Mopar ATF +4, about 20,000 miles ago. No other trans work performed yet.
Any ideas, thoughts or suggestions would be much appreciated.
Thanks in advance.

[Jaxom]

Here's an update from this weekend.
14 foot trailer, 2 quads & trailhead building tools, est. 3,000 lbs.
The noise/thump would happen at approximately 74 mph. Later in the day, between 70 & 74 mph.
That night after dropping off the trailer and with 1 quad in the bed I could duplicate the issue at 74 mph.
I am now thinking it might be a fuel issue??? Bad injector? Something that could interrupt fuel flow momentarily?
Any other guesses?
Thanks.

[Jaxom]

Well I finally had a chance to get into a repair shop. Hooked up a Snap-on diagnostic device and went for a 35-40 mile test drive. It seems like I have a bad "fuel actuator". Under warranty still so I will have to duplicate the test drive Monday, 7-20, at the dealership. Then we shall see what their response is. I have a flash upgrade that is due, as well as the H46 steering linkage recall.
Will let everyone know how it turns out.
Thanks for your help.

[RapidTransit]

Hi Jerry, keep us updated on the progress. good luck and thanks for posting here.

[Jaxom]

Just got back from the dealer. First thing they did was "flashed" the ECM/computer with the latest software version. Took a 72 mile test drive w/ the 5th wheel attached. Could not reproduce the banging/thumping. Hopefully that is the end of the problem. Time will tell...NO CHARGE!
Inspected the steering linkage and I have the good parts...NO CHARGE!!!

Time will tell if the bang/thump recurs or not. Meanwhile I am happy again.

Time to hook up the Smarty Jr. again. It was NOT detected by the StarScan!