Advice at 1 Million Miles

[JKBowman]

02/26/19

First post. Thanks for having me in.

The Truck:
Single Owner - 2013 Kenworth T660
ISX15 - 1.14 million miles - never rebuilt
History: - Pretty Easy (almost all long haul, 20K average)
- Not much snow. Rust hasn't been a big issue so far.

Last Overhead Adjustment (Cummins) approx 300K ago,
-- at the time mechanics said internals looked "really good"
-- they thought I'd only need top end, when needed

Oil usage - on new oil, maybe a gallon over the first 5 thousand.
-- I use 1 gallon of Delvac after oil change, then Lucas next gallon, then back to Delvac
-- didn't use Lucas at all prior to 800,000

Oil Analysis - last one maybe 100K ago, but it looked good.
-- I'd get it more often but it seems the dang Speedco machine is always broken

Currently in shop for:
Replacing remanufactured DPF with another remanufactured DPF
- got 266,000 miles on the old one

Not in shop for, but have:
Leaking oil at gear housing -- (not badly, but there's a definite leak)
Leaking oil at flywheel housing -- (not badly, but there's a definite leak)

Questions:

1) What can I do to determine if a rebuild is needed now?

She's running fine, but I worry about breaking down somewhere and not being able to get into the shop of my choice.

2) Any thoughts on a truck with this many miles?

I realize rebuild is not my only option. I think it's the my best choice (truck is paid for), but should I be considering something else?

Thanks.