1993 fzj80 auto wont stay in 1st gear (1 Viewer)

[Fazza01]

Got a bit of a weird one.
1993 fzj80 auto won't stay in 1st gear when shifter selected to L and will shift between 1st and second but no higher. The shift happens at sub 3k rpm most times unless giving it a boot full then it might hold on slightly longer some times.
Shift linkage has been adjusted and the 2nd light comes off cluster when going into L but the L light doesn't come on but may be blown. 2 D N R P all work fine.

Any help would be greatly appreciated !!

 

[baldilocks]

It’s unlikely that the indicator light is burned out since it takes many years to kill the D light which is illuminated for all those miles showing on your odometer. Couple the fact that your light is not coming on with the unwanted shift from manually selected low up into 2nd, I’d say you have a problem with the neutral safety switch or related wiring/connectors.

There are threads where owners found the barrel connector for that switch to be very degraded with corrosion due to it being dripped on by a slow and on going coolant leak.

You could try disconnecting the wire harness from the drivers side of the transmission located basically at the midpoint of the trans front to back. Then go for a test drive starting off in manual low. You should be required to shift through the gears manually to get any shifts at all.

 

[Fazza01]

It’s unlikely that the indicator light is burned out since it takes many years to kill the D light which is illuminated for all those miles showing on your odometer. Couple the fact that your light is not coming on with the unwanted shift from manually selected low up into 2nd, I’d say you have a problem with the neutral safety switch or related wiring/connectors.

There are threads where owners found the barrel connector for that switch to be very degraded with corrosion due to it being dripped on by a slow and on going coolant leak.

You could try disconnecting the wire harness from the drivers side of the transmission located basically at the midpoint of the trans front to back. Then go for a test drive starting off in manual low. You should be required to shift through the gears manually to get any shifts at all.

Legend yeah the barrell connector looked OK but ilk check the rest of the harness too. So if I unplug the neutral park/gear position switch I can override it and manually shift?

 

[Jason hansen]

My 96 was doing the same thing. I removed the aftermarket car alarm that had many ties into the wiring harness including the neutral safety switch. That fixed my problem of the transmission not staying in 1st gear when descending and up shifting to 2nd, it also fixed my cruise control. I know it sounds weird but I was out of options an decided the remove the car alarm to clean up the wiring and accidentally fixed the problem.

 

[Jason hansen]

My problem was I little different but I hope this helps.

 

[baldilocks]

Legend yeah the barrell connector looked OK but ilk check the rest of the harness too. So if I unplug the neutral park/gear position switch I can override it and manually shift?

No, not the neutral/park switch. Disconnect the wire harness from the circuit of the 4 shift solenoids to isolate them. This way the transmission ecu no longer has control. The connector with the blue tape over it that’s aft of the N/P switch.