roadrunner81
Senior Member
- Joined
- Dec 22, 2009
- Messages
- 275
- Location
- Tacoma Washington
- Occupation
- Managing member KSR Excavating, LLC
Picked up a 1973 Kenworth tractor not to long ago with a fresh big cam cummins and a 13 speed rto 1213. Problem is that I,m cranking along at 18-1900 rpm at around 55mph. I tried looking up tranny specs for ratios but seems to me that rpm and road speed combined with 24.5r11 and 4.33 would give me a 1.00 ratio. If I try a .85 It shows 65 at same engine speed? I really would like to find another transmission that would allow me to do 65 or so at same or less engine speed and looking for pointers? Found a rebuilt rto 14613 on local cl just want to avoid being in the same boat.