Steering and braking would depend on how and where it was used and greased. The 1999 would have the Caps fuel system which can have issues. there are lots of posts on the forum about this.
That said there are lots of them out there trouble free. The ISC has been a bullet proof engine and the Allison should not be a problem either. Another thing with the ISC is they have a problem with the exhaust manifold cracking. Usually a $1000. bill with labor. On mine the new one was much more robust than the original.
I have the same engine trans. in my coach and am very happy with it. There are the odd times I wish it had a little more power on steep uphill grades but hey I'm retired so what the heck.