Something wrong in these numbers.6 cylinders in a row vs 3 cylinders in a row...Confirm sources over and over, the internet is total $#!% when it comes to this info...When I type $#!%, I'd like it to say $HIT...happy coaching!buswarrior
I know a couple of bus people with this combo in the 102C3 and it works great! The nice thing about the HD4060 is the first four gears are just about identical ratio wise to the HT740. And the fact that the ISM can put out more torque than the 6V-92TA (1550lb/ft in RV form), I don't believe you'd have to switch out the rear end ratio. For sake of discussion-if you have 12R-22.5 that's a 485rpm tire. So with your 3.36 rear end, at 60 you'll turn 1629rpm. At 70 you'll be at 1901rpm and at 75 you'll be at 2037rpm. 5th gear is a .74 overdrive. At 60 you'll turn 1205, at 70 you'll be at 1409, and 75 at 1507. You want to be somewhere between 1400 and 1800 cruising with the Cummins ISM-so nothing wrong with using 3.36-you'll just not be able to drop into 6th till 80. At 2100 in 6th (.64 overdrive) you'll be going 121mph (you won't have enough horsepower to go that fast). But at 80 in 6th you'll be at 1390-probably again not enough horsepower. But there is nothing wrong with blocking 6th gear out-it's just a programming issue. Good Luck, TomC
If the transmission is already programmed for 6 speeds, then nothing else needs to be done. The transmission will only shift into 6th when appropriate, and will down shift as necessary. If you get a hunting situation between 5th and 6th, simply push the down arrow to hold it into 5th-done!I would also just rebuild the 6V-92TA. Parts are going to be around for a long time-only thing is finding suitable mechanics that can work on them. Good Luck, TomC