Maxitourqe 18 speed

Never driven a Mack 18 speed, but I do know that some Mack trans can be tempermetal. They seem to have a rougher feel than others.

 

Maybe this will help.

 

Rpms depend on the engine, not the transmission.

My limited time in a Mack was a truck that was designed for very high rpms, regularly went over 2k, I think cruising rpms were around 1700.

 

Forget about what RPM to initiate your shift. It'll drop about 200 RPM splitting, and 400 RPM shifting a full gear. To split within a gear, select your split, lift off the throttle, let the RPM's drop enough to catch the gear, and ease back into the throttle. To split while shifting to a different gear, start your shift and split as you pass through neutral. If you pre-select your split when also changing gears, you run the risk of it grabbing the next gear as you're trying to get the shifter out of gear...and that is hard on the transmission, driveline, and makes you look like a rookie to anyone in the viscinity.

With that having been said, if I'm going uphill loaded or trying to get up to speed in a hurry (such as merging onto the highway), I'll run it up to 1800 or so so that I'm in the peak power band in the next gear. If I'm just accelerating normally, I might shift at 1600 and just keep easing it up to speed. Like I said, the RPM at which you initiate the shift doesn't matter, because it'll drop the same RPM either way. You just want to pick your shift point to keep the truck in its power band as you're accelerating up to speed.

 

If its not working sometimes its best to go back to the operating manual and see what it suggests other than that just try experimenting abit without putting to much stress on the gear box try shifting at lower rev's see if that works, its usually all about matching speeds and rev's regardless of the make of the gear box.