$10,000: fix or sell?

[magnus caeruleus avis]

Theres always folk who can call the game perfectly on Monday after its played on
Saturday. I am certainly sympathetic to someone who loses an engine.

My experience and techno-challenged opinion - on the way to Corpus Christi
winter before last, I noticed my tranny warning light come on and to my dismay
the tranny temp was approaching 250. I called Allison road service and it was
determined my fan was not working properly on auto. The Allison tech checked my
engine and tranny and advised to run the fan on manual all the time. I did and
no more problems on that trip - tranny temps stayed between 190-200, maybe 210.
Come to find out I had an alarmstat go south - one of the least expensive parts
on our birds. Got it replaced, but I still run my fan on manual all the time. I
know there are some nay-sayers, but I feel comfortable with it - seems to make
everything cooler - engine, tranny, water, etc.

Using that strategy I drove this past month 5500 miles through some of the
hottest OAT's I have ever seen (100-110 S. Texas, NM, Arizona and between Las
Vegas and Needles 114. Temps were constant 180 to 190 on water, ever once in
awhile tranny would hit 220 - 230 but usually stayed right at 200-210. I'm happy
and I think my engine and transmission were happy.

On long grades if I saw a trend in climbing temps, I would pull over, shut
everything down except the genny and roof a/c's sit for 30-40 minutes and let
'er cool down.

Of course I find out I've been using the wrong oil for the last 40,000 miles
(Dello 400 instad of 100) Thanks Tom Warner for your comment and warning. I hope
I haven't screwed up too bad.........