trans ????

the 7 is helical aux gearing and multi-mesh front section gearing. the 9 is improved seal system. the ll is 2 low gears

 

The 9LL is a specialty transmission designed for concrete mixers. They need a extreme low gear to crawl along with a slip form curbing machine. Its low low gear is more than twice as slow as a normal 9 speed. I believe you 9 has a low gear of 12.32 to 1. For every 12.32 time the engine turns the out put of the trans turns once. The 9LL has a low low of 26.08 to 1. Its a great trans for slow manuvering and heavy off roading. Ive seen them in dump trucks and other special purpose off high way truck like oil field trucks, well drillers, and concrete pump trucks. It actually has 11 forward speeds and 3 reverse. You split low and 1st like a 13 or 18 speed then shift 2 thru 8 like a normal trans. This is not your typical OTR tractor trans. Will It work? Sure. Will It cost more than a straight 9 speed? I think so. Will you ever use thoes extreme low gears? Prob not, but in a tight manuver or a real steep start with a full load they would be nice. I would see about getting you old trans rebuilt. We just had a 8LL rebuit for $2600. A reman was $3700. If you want some thing different other than you 9 speed look for a "RTLOC" 9 speed. The "c" stands for "convertable" and it can be turned into a 13 speed. Your old 9 can not. Or just find a 13 or 18 speed and be happy.