I've been trying to improve on running our 43 meter putz, but has a slight issue with the motor rpms. Sometimes when your pumping in 9th gear the motor rpms will fall on their face to like 1350 or so. It may happen on setup, while pumping or cleaning up, and sometimes they will come back up. Now in saying this, in 10th gear the motor will rev over the cutoff of 1350 or whatever and it will kick out and start back at the bottom of the rpms. We let Mack hook it up to the computer and they fixed the 10th gear lockout switch. I pumped with it today and everything went well except for the waterhose busted and soaking my ass from head to toe. Would the 10th gear Lockout switch have an effect on the rpms even though the truck is Pumping in 9th?

i changed mine on 01 42m putz cause it was doing same thing but ended up making a shim for it because it was pushing down on switch too much and locking it out in either gear now it works fine

Yes it can have an effect on the RPM Also check the Spedo sensor on the Tail shaft of the Mack Trans, If it gets enough metal particulates built up on the sensor it will play heck with the Mack ECM. Be careful though when screwing the sensor back in check with your local Mack dealer as to the proper depth setting. If you screw it in to far you will damage the sensor.

 Travelteck:  Have had to replace a few of these.  The procedure direct from Mack,  Screw the new sensor in until it bottoms out by hand then back it out one full revolution then use the jam nut to secure it into place.  Its a 10 minute job and the sensors are fairly cheap.  You will also get a electronic malfunction light on the ecm display.  Don,t have my book handy or else I would give you the blink code.  Hope this helps not trying to step on your toes.

Thanks Granddad, It takes a team no one remembers it all. And I have steel toe boots.

Considering most days my feet are the size of sideshow Bobs, it doesn,t take to big a step before I'm turning red in the face and saying sorry, step, sorry, step, sorry.