13 Speed: Probably a stupid question, but...

It could be either way. The old 13 was an overdrive box. I think some if not all new 13 they are an under drive. I know you can build em either way.

 

The old old 13 directs used an under drive box.

 

Freaking phone messing me up cannot delete

 

Had to train a jb driver coming off the road on one. Owner and mechanic both tried to teach him but he could not get it. I had him good in an hour. Dude was crying, it was a local job and he did not want to not get it and have to go back otr. Boss gave me 3 hours for him to get it down. We had several mack twin sticks too, he was lucky.

 

It was for dumps and construction uses.

 

That was the 6613. With a DR. The under drive was not a deep reduction. They used em in road tractors back in the early to mid '70's. Back when a big motor was 318 horse power. They didn't have enough balls to push an overdrive.

 

Of course I wouldn't be a bit surprised to find em in a vocational unit

 

I replaced my 10 spd with a 13 spd this year. I didn't get anything for my 10 spd as a core and you will have to get the driveshaft shortened. From a business perspective i don't think that it is worth the expense if you are only grossing 80k. It is nice to have in the hills though. I would look at regearing the rears if you want to climb hills better provided that you don't have a mechanical issue. I've been pulling a 3 axle trailer for the last couple of years with 430 hp, 10 spd, and 3.36 rears through ky, tn, Al, oh and it got the job done granted I don't run out west.

 

I had it in a tri axle dump, biggest in the fleet, nobody wanted her, they couldn't get the pattern down, i had it down quick enough. Had the truck all to my lonesome. Others would take a half day rather than drive it. No slip seating for me!

 

This is the official word from our mechanic.
" I don't know ".
So that's that.