New to me 2001 770 n-14 & gen 1 autoshift 970K miles

Hello all, got the above truck a couple weeks ago, as my own, working on getting my own DOT#'s etc.

question on truck and options ---if anyone knows/ can help.. its the 3 pedal autoshift.-- has a TCS button on the dash- I think its "traction control system" but not sure, there is no DIFF lock button, on the dash, so does this TCS button do the same thing? Or does the 2nd set of drivers automatically kick in when needed? anyone familiar with this?

I noticed the driveline yokes are a couple of splined teeth off- from one end compared to the other- IS this OK or should i re-index them to be inline? I have NOT noticed any driveline vibrations or issues yet.

At the front pass side of the truck- in the engine compartment, there is a tall cylinder with a cap- with a "sight glass hose" along the length of it- top to bottom. at the very bottom of this cylinder/ container is a hose about 1" in dia, with a hand shut off valve.. there is NOT a wetkit on the truck. so any ideas what this is for? even the last owner didnt know waht it was for.

ON truck itself- CUMMINS N-14 autoshift at 500 HP- new injectors 6 mo ago, new fan clutch, hub bearings, xyshifter, belts, some hoses, new steers, new pinion seals, couple of new air fittings, new gear indicator on dash. new steering gear, tire rods, bushings, radiator, waterpump, alternator. Truck has working inverter, fridge, micro, tv, etc, truck is in decent shape for the mileage and age, FULLY serviced front to back 6 months ago while having the other things replaced. Im the 3rd owner. truck has been O/O since new, leased to a couple different companies...

is there anything else I should be looking for/ checking on this particular truck before running some loads far from home?? tips?? thanks Guys, much appreciated.