Allison 5sp: Stuck in 3rd!

REDHOSS02

REDHOSS02

hard n heavy
Jan 14, 2009
280
0
0
F U im from TEXAS
The last two days i have noticed that when i shift from park the dash does not highlight PARK NEUTRAL OR DRIVE, it will notice that its in REVERSE, 3, 2,1. if i put it in drive it will not highlight it but will go into drive but the problem is it stays in third gear all the time. if i want to start out in low gear i have to put it in 3 and it will go through 1st 2nd but wont shift past 3rd. i have had two people tell me its the mlp sensor! any info or part #'s to help me out? thanks guys!
 
REDHOSS02

REDHOSS02

hard n heavy
Jan 14, 2009
280
0
0
F U im from TEXAS
yea it threw a code but ill have to call and get it! i forgot what it was. isnt the nsbu switch in the mlp? None of this started till we had all this snow down here and i was think maybe some water got in there because the plugs going in should be tight and they have some play in them. i tried to wiggle them to try and get a better connection but nothing!
 
kjp800

kjp800

-
Aug 6, 2008
525
0
0
New Jersey
I'd check the NSBU switch. Some of the early ones had some issues with getting water/snow/dirt in them and since you said you had snow that would make sense.

Its located on the drivers side, slides over the selector shaft that the cables hooked too
 
JoshH

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,598
631
113
Texas!!!
NSBU stand for neutral safety back up switch (tells the truck the trans is in neutral or pak so it can start and turns on the back up lamps). It's also called the PRNDL switch (for park, reverse, netrual, drive, low). I've never heard of an mlp. What's that?
 
JoshH

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,598
631
113
Texas!!!
It's all one switch. It controls the display, and tells the truck what gear is selected. If it is messed up, it throws codes and puts the trans in limp mode. What's an mpl?
 
JoshH

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,598
631
113
Texas!!!
REDHOSS02 said:
manual lever position sensor! or major league pu55y! the truck will start in park and neutral it just wont hightlight PND&2
Click to expand...
Sounds like we're talking about the same thing. The manual lever position sensor, as you call it, is the neutral safety backup switch. Like I said before, it's also called the PRNDL (pronounced prindle) switch.
 
REDHOSS02

REDHOSS02

hard n heavy
Jan 14, 2009
280
0
0
F U im from TEXAS
im not saying your wrong i believe you 100% but i am just saying from what its doing you think it would be that switch? where can i find one cheap? the stealer wants $240 for it!
 
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