I can help with some of it.
My 1999 Volvo has 350,000 miles on it.
A standard trany “fuller” 10 speed holds 3 gal of oil
6 cylinders 12.7 liter Detroit 470 hp @ 1700 rpm 1800 fp of torque.
Miles per gal. is 5.9 to 6.3 depending on how much idleing I do
I change oil every 3000 Gal of fuel or aprox. every 18,000 miles,
The crankcase holds 9 gal. and the 3 filters hold another gal.
Coolant holds 11 gal ( just changed it )
I think the tractor weighs about 17,000 alone and 43,720 with the empty 10 car hauler on it.
Max legal weight is 80,000 of coarse the rig would easily handle 100,000 gross.
With 10 heavy cars on it I get right up to 80,000, I have to watch the amount of fuel I have on, the 300 gal adds 1800 pounds but lets my go 1800 miles between fills.
The suspension is air the cab rides on air and the seat has 5 inches of air travel.
Great ride …..very smooth.
I usually start out in 4th or 5th and shift at 1700, the last 3 gears are the real pullers your not in the first 7 gears long enough for the turbo to spool up (no power without turbo spooled to the max.
In top gear the engine turns 1475 rpm at 70 mph.
These engines run and run and run a friend of mine never shuts his off between services, he drives team and puts on 15,000 every 3 weeks.
Rebuild on the engines are usually done around 650,000 miles, many go 1 mil. Miles.
Manufacture says the first scheduled service of the trany and rear ends is 500,000.

-mark

BTW my car is a 99 s500