10 spd to 13spd or 18spd conversion

Need shortened drive shaft.

 

13 and 18 have an additional auxiliary box on them.. longer transmission, so a shorter driveshaft will be needed. Also, you'll want to know what the final drive ratio on your current transmission is, because that 13 or 18 is going to be a .73 or .74 OD. If you're running, say, 10 direct and 2.64s, you won't appreciate the difference very much, but if you're running a .74 OD already, then of course a .74 13 or 18 speed will be more the same, and the difference with a .73 will be very slight.

 

keep the 10 speed and install 3.55 or 3.70 rears after a cost analysis between the trans replace or rears.

 

You will love the 18B or a 13A. The 18B will have a lower low and reverse.

 

Trans is cheaper I bet.

 

My last two trucks had 18 speeds. Bought this one for the 6NZ, but it had a 10 speed. It was expensive but I pulled the 10 out and put a reman 18 in. Expensive, Rush peterbilt and you eat most of the core. Would I do it again? Yes!!!!!!!!

 

I a mbn have 10 sp 16210c with 3.70. tuned to 500 hp. Has .73 on 10th gear. Only gets 5.1 mpg. Best I had is 5.7 mpg after valve adjustments. I had thoughts of putting 13 sp on it. What's your advice other than the cost?

 

If you're doing it for the fuel mileage, those 3.70s are gonna be your biggest hindrance.