Nnbs problem
 

Have a 2007 nnbs with the 4.8 and im noticing a slight problem. Truck runs great but while sitting in traffic the coolant temp is creeping up and as it creeps up the tranny temp starts to also. Truck has 50,000 miles and i never noticed issue before.

Usually truck runs at about 210 degrees with roughly 170 degree tranny temp but as of lately ive been seeing 220-230 degree coolant temps and 200 degree tranny temps... Only in traffic. Any ideas?

Start with the basics. What mods do you have? Is the coolant full? Are your radiator fans coming on?

Coolant full and fans come on and also just have intake/exhaust

Confirm guage readings and move on from there. I use lazer temp gun.

get a 160 thermostat and put ur fans to 90 % duty

The factoy gauge is way off. Id hook up efilive or hpt and see what its really at.

any debris in the radiator?

I have an 07 silvy nbs with the 4.8. it has the trailering package and is a z71.
when I was driving really slow down a gravel road (leading for a tractor we were moving) i noticed my trans temp rose to *180. it has a seperate trans cooler, but it didnt help much at slow speeds (less than 10 mph). soon as i gave it a little gas, it cooled down. im gonna say your fine.

Can i install a 160 thermostat without a tune or anything? And keep fans at factory turn on temp? Or will that defeat purpose? And what would yall suggest for external tranny cooler? Mine has internal in radiator? Install tips?

radiator is full of dirt and bugs.A/C condensor too

Not a bug in either just had grill out and looked.