HMMWV - M1151-A1 - Transmission Neutral Safety Switch replacement

[Mastherr]

On M1151-A1, To replace the neutral safety switch you will need to remove the “Shift Control Housing”. See below a few pics and video to help you do it.

YouTube video: https://m.youtube.com/shorts/btn-vrgsLLA

Manual: TM 9-2320-387-24-1
Procedure 5-6 (page 5-15)

tools:
- 7/16” (or 11mm) socket (ideally 2 sets: one long extension to help access from below)
- Phillips screwdriver
- Needle nose pliers (for the safety pins)
- new safety pins (I’ve reused mine since I didn’t have any)

parts:
Neutral safety switch:
12338434 5597263 2920-01-249-3492

Comments:
- underneath the Humvee find the shift control housing silver protective cover, open it from below
- disconnect 2 wires labeled 14 and one 18
- there are 2 arms connecting the transmission to the shift control. Remove the 2 safety pins (see video)
- unhook the arms, now the shift control is loose to be removed from the cabin
- to remove the 4 screws holding the shift control in place (watch video) I suggest 2 people (makes life much easier)
- I don’t have help, so I improvised with a wise-grip plyer to hold the locking-nut under carriage. I’ve located the screws, place the plyer and went back to the cabin to easily remove the 4 screws holding shift housing
- remove the 2 Philips screws on the passenger side
- remove the neutral switch
- unscrew the old switch from the square aluminum piece
- replace for the new, reverse the installation
- (alternative mounting procedure): use rivnuts from the cabin to make your life WAAAAY easier (Tks Coug)

 

[Coug]

Two things to note.

1) Unless something changed, it should be 7/16" wrenches/sockets, not 11mm. 11mm is close, but the bolts in that area should be standard.

2)Once you remove the shift assembly once, it's a good idea to go ahead and install rivnuts in the holes if you don't already have them. With rivnuts for the shifter, you no longer have to have someone under the truck or use visegrips to hold the nut. Just make sure to use some anti-sieze on the bolts to prevent corrosion.

 

[Mastherr]

Two things to note.

1) Unless something changed, it should be 7/16" wrenches/sockets, not 11mm. 11mm is close, but the bolts in that area should be standard.

2)Once you remove the shift assembly once, it's a good idea to go ahead and install rivnuts in the holes if you don't already have them. With rivnuts for the shifter, you no longer have to have someone under the truck or use visegrips to hold the nut. Just make sure to use some anti-sieze on the bolts to prevent corrosion.

…never thought of the rivnuts alternative, great idea. I wish I hadn’t reinstalled it the old way