it is always hunting for gears when in traffic

so, it's working correclty then.

 

It's operating normally. Put the shifter in M and use the +/- buttons to select the highest gear you want while in traffic. It's not a 'manual mode', it just limits the highest gear to what you've selected. Or you can use tow-haul all the time. Or you can do both of those things at the same time. You're not going to hurt anything except your MPG just a bit.

 

I should’ve specified, when at lower speed like 15-40 mph it’s always shifting up and down and jerking into gears when I let off throttle.

 

The truck is factory tuned to upshift as soon as possible to keep the rpm's down for maximum MPG and lowest emissions. Then a change in throttle and it downshifts. It's just the way it is. Depending on the year of your truck, a tune could greatly improve that behavior.

 

Maybe I’ll try doing that, I appreciate it

 

When I got my first 8-speed (in my Toyota car) I had the same reaction as you. So long as you're not under a heavy load, that "hunting around" is not a big concern (it's part of the fuel saving economy). If you are towing, yes, use tow mode and maybe even drop it into 5th gear.

 

You can run tow/haul 100% of the time if desired

 

When I had a 6 speed automatic car for a while it kind of drove me nuts how often it shifted. I'm of the (probably wrong) mindset that the more often something gets used or is operating mechanically - the sooner it will need repair or wear out. Although much less efficient, that's what I like about the 460LE transmission in my Silverado. Same with the 4EAT in my Subaru. Cave-man technology by today's standards - but I like them both. They rarely 'hunt.'. The torque converter will disengage and re-engage on uphill grades, and occasionally drop down to 3rd gear.

 

Correcting the the self destructive tuning is the best way to prevent premature failure, when combined with keeping the correct fluid and filter clean. And for what it’s worth “the manual” isn’t necessarily your friend for fluid and filter change intervals, on the whole vehicle.