Allison Transmission Neutral Safety Switch Problems

Here the culprit is often the neutral safety backup switch.

Allison transmission neutral safety switch problems.

The purpose of the neutral safety switch is to prevent the car from starting while in gear which would cause it to launch forward unexpectedly. The neutral safety switch is a safety device that only allows you to start your engine when the automatic transmission is in either park or neutral. It is part number 29540479. Neutral safety backup switch issues are another common allison transmission problem on the gm duramax versions.

It is part number 29540479. Descriptionone of the most common problems with the allison transmission is failure of the neutral safety back up switch. Neutral safety backup switch or park neutral position switch provide the tcm with signals to indicate selected gear range. Has anyone here had to have their park neutral safety switch replaced on their allison transmission.

One of the most common problems with the allison transmission is failure of the neutral safety back up switch. If the d doesn t light up on your gear indicator this could be the issue. Thanks mike l problem i have is the truck will not shift into high gear and the dealer can t figure it out says go to allison at 35 mph. If so what problems was your transmission giving you before you replaced the switch.

I have a p n 29541852 1 connector. It developed a problem on route yesterday and would no longer drive the bus. I have found a tsb 02 07 30 011c that seems to cover my problems. Our school has a 2007 ih bus with dt466 and 2500pts allison trans.

Allison transmission 29540479 nsbu switch kit 2001 2005 lb7 lly 5 speed 2 plug. After jumping across the solenoid and getting the engine started the bus had both forward and reverse movement. This switch is the dual plug style that can be found on any 01 05 lb7 or lly. You should understand there is a problem if you cannot see the d light up on your gear indicator.

I suspect neutral safety backup switch as they do get crudded up and i haven t put back my fenderwells since other work. Some of the symptoms of failure include but are not limited to no start condition gear shift indicator on dash not following properly trans stuck in limp mode or fail safe dtc s set indicating pressure switch codes this switch easily installs with just common hand tools. Input speed sensor provides the tcm with a signal to measure the rotating speed of the turbine shaft from which it can calculate transmission rpm and slip.