Ok, so first, thank you all for all of the previous help with my issues. You all have been amazing. I have a couple of remaining issues but we will address the most important first.

When accelerating I can hear a click/ticking noise come from under the vehicle, sounds like it is toward the front.

Front diff has new fluid and is confirmed to top of drain plug. New front driveshaft installed about a year ago. I've always made sure to grease it with every oil change. Took it completely out today and do not feel any play and any of the u-joints. Made sure was full of grease and re-installed. I notice it most when going up a hill or when there is tension in forward motion.

What could it be?

 

Can you specify whether it is rotational with the drive train or with the engine?

Recently had my rear drive shaft start clicking only noticeable at low speed... in time with the wheels rotating including in neutral... Turned out the bolts had started to come loose!

Also if it is in time with acceleration/engine RPM related you could have an exhaust leak or head gasket external leak or a few other issues...

 

It is rotational with the drive trail. Does not make a noise in neutral when given gas. If I am driving and let off the gas or coast down a hill, the noise goes away. The sound does speed up the faster I go.

The sound is not coming from the engine, as it cannot be repeated unless the vehicle is moving or under pressure.

 

Axle / Half Shaft? Have you checked the CV boots?

 

Boots both look good, attached and no cracks. It is a 15 year old vehicle with almost 150k miles so might be CV. I've only had the truck for about 2 years and trying to catch up on all old maintenance items. I would assume even with boots intact that the grease could still be bad or gone.

I will note, the sound doesn't appear to change when turning or rotating wheel

 

You don't mention if you've been servicing the rear driveshaft... Check the torque on the flange bolts at the front of the rear driveshaft on the parking brake drum and at the rotoflex. Inspect rotoflex visually for cracks. There is a center ball in the rotoflex end that never gets serviced also... In my case the rear shaft only made noise under load, could not replicate the noise by jacking up a rear tire and turning the wheel by hand. no visible signs.

Another known random click is from a loose inside mounted wheel weight hitting the brake parts.

 

I do service the rear driveshaft when I do the front at every oil change. I've also replace the front and rear driveshaft, along with the rotoflex, all about a year ago. The rotoflex still looks good but will check torque in both ends tomorrow.

Is there a way to service the center ball in the rotoflex end?

I did check the weights to make sure and all is okay there. The crazy thing is, the clicking is only about 75% of the time. There are days that it won't click at all, but then the next day it will. I've had this issue for about 3 months trying to diagnose it

 

90% chance it is the first indications of a failing front drive shaft. You need to do a super good inspection of it - get under the truck and take some well lit high res photos, don't drive it very fast or far until you post pics and have us look at it - or take it out and feel the joint and see if they move smoothly (only 8 bolts). If it fails while you are driving it you will be buying a new driveshaft, transmission, and transfer case. Be very careful.

 

That was my first thought, was the front driveshaft. I've greased it probably 10 times in the last 3 months thinking that maybe I wasn't getting all the old out, or wheatever, lol. I took it out today and checked all u-joints and there is absolutely 0 play at any of the joints.

 

Does your front drive shaft have a spot to grease the internal bearing of the cardan joint? Normally, you have to drop the upper end and move the cardan joint around to expose the grease zerk (which will most likely be a small indentation and takes a special grease fitting to apply grease).

Have you checked your transfer case fluid?

Brian.