Transmission fluid type on 2016 t680

Transmission oil = 50W synthetic. Do you know how to check the oil on the tranmission and where to fill it? If so, get a vacuum pump (little squeeze ball with some clear tubing on either side), because you're not gonna successfully get the tip of that bottle into where that transmission fill plug is on the 680

Engine Oil = 15W40, API CJ4 rated.

Coolant = whatever your company uses. Some companies use the green coolant, some use the red Extended Life Coolant. Do not mix the two. Some fleets run that blue Cummins coolant, which is supposed to be blendable with either.

And 75W-90 gear oil is what's most commonly used in hubs and differentials. If your company uses a different weight, they can safely be blended.

 

I wouldn't be too concerned about transmission grease. An engine can burn oil, blow it past the rings and out the valves, as well as leaking in dozens of places. A transmission will leak at 2 places, the input shaft and output shaft. I have owned 5 trucks and been driving for 16 years. I have yet to add transmission grease.