18 speed

The 9LL and 8LL are low torque trannys, meaning if you want a big hammer under the hood you can't get one, thats prolly why they give you such a low ratio is because you got no power

 

8LL is a compromise tranny. Great for heavy duty off road stuff and still ok on highway. I have driven several of them lately for BNSF. They license them at 80k and pull pup trailer to haul ballast and other bulk stuff. Most are mated w/ 320 hp Mercedes engines. For mainly highway I would still go 13 or 18 spd.

 

Not sure I would call 1650 low torque. Maby middle of the road. you can still get 500hp. The 8LL iv seen in a lot of tractors. The 9LL only a few day cab heavy haul/ low boy type. Your right though as soon as you get over 1700lbs of torque a 10, 13, or 18 are your only choice for a stick.

 

I had an 8LL with a 500 detroit grossing 107,000lbs and it worked fine. Got an 18 now and its nicer but the 8LL worked fine.

 

here is the whole thing, if you haul heavy you need hp and torque, so in order to have that you can't have a little truck tranny. When you get on the road the 8LL will work the snot out of your truck, tach'n out every shift and screamin down the road. And an 8LL and a detroit would be alot of fun to drive 107K and flat ground would be all that thing wants if you wanted to hit the high side of the tranny

 

It ran just as good as an N14 500 and equeal to a 475 1750 cat on grades as steep as 12%. Actually ran better than the 14 liter 515( mine was a12.7) With same load and an 18. It was a good runing truck for a small cube engine. Yes I did wind it high before shifting but that where it made power. Now have an ISX cummins at 530 with an 18 and it is much better at 107,000lbs but the old Detroit worked real good for what it was.The ISX makes power much lower. Split at 1700 on 12% grade, 1500 on level ground. What a differance RPM wise from the detroit. The first day with it I think a rookie could have done better. It was sad.