Where to go for 13 speed

15 speed wont help with the big rpm drop 10th to 9th gear lo pro tires will bring up rpm 50 to 60 rpm which i found helped a lot in my case . 13 speed is better but more costly

 

If you get near Cleveland,Oh. try Premier Truck Parts 216-642-5000. Friend of mine gave them his old 10sp for one of their rebuilt 13sp's. $4200.00 no sales tax in Oh. He put it in himself and another friend built a driveshaft.

 

Can't you buy parts from a vin with a 13spd from the dealer?

 

What you're talking about sounds more like a 10LL than a 15 speed... a 15 speed is the same principle as a 13 speed... you split the top range just like with a 13, but instead it's a 10 speed shift pattern instead of the H pattern. So if you have, say, a .74 OD on your 10 speed, then the conversion will allow you to go .87 in 10 low and .74 in 10 high, etc.

 

Columbias... for the last 40 years?

 

Slight miscalculation on my part.. I think a .74OD transmission in the big hole would actually be .86 on the low side of that gear when split... not a life changing difference, but I tend to be nitpicky that way.