99 or 97 kenworth w900l

I would say it depends on how far you are planning on running. If its just local get the cheapest. Whats the HP rating on the DD? It seems to me to be the better choice, even with it needing drives, as with the DD and overhaul it might have better resale.

If your heavy and have lots of hills you might be better off with the Cat and 13speed, but who knows if its reliable?

 

With all of that, I would probably go with the cat. Keep your foot off the gas and use the splitter to keep the RPM's in the sweet spot.

I haul 105,000 line haul, and being heavy with hills the 13 speed does make a difference. You should ask them to put the good drives on that one for you. (Never hurts to ask lol).

 

Just make sure that the brakes are good, and that it has a Jake on it.

 

The only problem with the cat is that it is very expensive to rebuild. Sooner or later that day.is going to come.

You could always get the Detroit, get some performance upgrades, put in an 18 speed for your mountains. Then you would have a truck with new engine, new trans and clutch, and a truck that you have less money into that is set up the way that you want. You could go a loooong time without worrying about your driveline. Just a thought.

 

Living in the mountains I would also take the cat. If it has only about 300000 miles on the rebuild it should be good to go. You did not mention what rears are in each. That can be one of the deciding factors. If you have a rear that is geared wrong you have not accomplished anything.

 

Go with the cat. Low Pro tires would actually give you a little bit more pulling power, but with 550 its kinda a moot point.

 

Another thought is the detroit is a fresh overhaul. If buying a fresh overhaul I like to see 30000 mile at least. If it wasn't done right it usually shows by then. New parts are useless when installed improperly. The CAT has enough miles to show its rebuild will hold. I have seen many new engines fail due to sloppy work.

If you buy the detroit put drives on it performance upgrades and an 18 speed you will have at least another 6000 in it.

True the CAT is older and a little more money but its rigged to do the job at hand. And the tall rubber will be a plus for what you do. We run a 2000 model 379 with a cat and 18 with 3.36 and my old 359 with a cat and 13 with 3.55. Haul grain with the 379 and cattle with the 359, both are heavy all the time and the tall rubber is nice for clearance.