M548 won't shift

[Pclarkfarms]

Hi y'all we have a m548 rigged up as a woodland fire truck. It went down in the last fires we had here in the Texas panhandle. I finally have time to mess with it. The transmission oil light it on and it won't shift out of 1st gear. Tranny fluid is full and looks clean. Reverse works fine first runs fine it just won't up shift. Just looking for some info on where to start looking if anyone knows. Not much info out there on these things. Thank a bunch.

 

[dmetalmiki]

Some more detail of what's going on would help, (The transmission oil light it on?) Do you mean is on?, and "wont shift out" means it is stuck? (lever wise?), Or, it can be shifted or gears selected but will not Up shift from first gear. Research the gearbox type, and trouble shoot from there as a start. AM or shop manual net search would be revealing.

 

[Pclarkfarms]

Yes the oil light is on. The lever shifts fine through all ranges it won't shift to 2nd or 3rd.

 

[snowtrac nome]

if I remember right the trans is a tx 100 its just an early version of an Allison 500 series it sounds like you have a governor that is stuck. they are usually accessible externally but may be a sob to get to in an m548. I don't think the light has any thing to do with it unless somebody cooked it and fried the switch. the trans is all mechanical with no electronic controls.

 

[dmetalmiki]

Hopefully someone with experience with the type will come to the fore.

 

[dmetalmiki]

Research and trouble shoot this (Type of) Allison TX-100-1 3-speed automatic transmission,

 

[Pclarkfarms]

Thank y all. I'll research the governors. It don't seem burnt but could be. All other autos I've had burn up you could smell and tell it in the oil but this oil is clean.

 

[155mm]

When was the filters changed last? Makes me think the filters got plugged when it was put to use.

Other question, did you go thru the troubleshooting in the 9-2350-247-20 for a trans psi light?

Where here in the panhandle are you? It might be easier if I come look at it in person.

 

[Pclarkfarms]

The light is off it was a wiring deal. The trans still not shifting on its own. I can run in 1-3 and it stays in 1st if I shift up to 2-3 it'll go to second but never grab 3rd. As soon as you shift back down to 1-3 it'll shift back to 1st. It's been a few years since the tranny filter has been changed I'd guess. I've never done it. It worked fine in the March fires. The fuel cap came off at some point and filled the tank with sand and ash took out an injector. I put injectors in it and a different fuel tank. Been sitting since March just now got it all running and now the shifting deal. It shifted fine before the fuel problems. It is in Miami TX.