2014 Volvo self braking

My first thoughts are that you're a new driver and your jake brake is on...

 

To close to the vehicle in front of you collision avoidance system?

 

probably collision avoidance system, or engine brake is on.

 

Could be a drive stability system or ATC. PITA to diagnose. If drums are not hot she is engine derating or internal parasitic load such as differentials, locked bearings. Check the diff loc switch and make sure solenoid is not leaky.

 

New driver?

 

Driving on "L" maybe...instead of "D"

That will slow down the truck (more rapidly) upon easing off the go-pedal

 

Certain models have an automatic setting on the Jake which will function as a sort of "downhill cruise control" when the cruise control is on but not active. When the cruise is active, it acts as an automatic speed limiter on uneven terrain.

 

My truck seemed to brake its self a couple times in the first part of a curve in a construction zone. I pull a tanker and was trying to figure out if I may have been going a little to fast and also the fluid shifting. I thought maybe it was the traction control but it did not come up on the dash display. I didn't worry about it much but I am curious now that I see this thread.

 

Does your truck have any sort of collision avoidance option -- such as the "Wingman" or VORAD? If not, then it sounds more like you have the stability control sensing some lateral instability (such as, like you thought, fluid shifting a bit).
If you have the collision avoidance radar, it is notorious giving a false warning on the road signs (such as a detour, where they have signs in the detour curve) -- I had that happen a lot in the 2016 KW T-680 I leased from Swift, until I finally got it into Inland Kenworth in Phoenix and they properly aimed the radar antenna on the front crossmember.