Lx went into low at 65 mph suddenly

[zoned]

After a torrential down pour and my normally garaged LX, my passenger seat warmer light was flashing so I figured I had water intrusion and it was wet, but what I didn’t plan on was driving down the road at highway speed then all of a sudden going 35 with the LO light flashing. It went away the first time and I continued on my almost pants soiled way. Then it did it again.
I turned the truck off and turned it back on and ran fine back to the house. Anyone else experienced this? Thank god I did have someone close behind me or it would have been bad.

 

[kcjaz]

You mean it down shifted itself to 1st gear? At 65mph (assuming 6 speed trans, stock gearing and tires) rpm’s would go from about 1600 to 9000. That would be quite a jolt.

 

[zoned]

You mean it down shifted itself to 1st gear? At 65mph (assuming 6 speed trans, stock gearing and tires) rpm’s would go from about 1600 to 9000. That would be quite a jolt.

I mean be off on my numbers as I was trying to figure out wtf was going on but imagine you stomping on the breaks at 65. That’s what it felt like and just the 4lo was flashing. Maybe it shifted into first but it felt like the transfer case just put it in 4lo scared the piss outta me.
just tore open the passenger stuff and took the leaf blower to it. A lot of water but nothing obvious on the plugs. Still can’t figure out why my passenger seat warmer indicator light is on. There is no wetness under the passenger seat where that plug is.

 

[zoned]

I mean be off on my numbers as I was trying to figure out wtf was going on but imagine you stomping on the breaks at 65. That’s what it felt like and just the 4lo was flashing. Maybe it shifted into first but it felt like the transfer case just put it in 4lo scared the piss outta me.
just tore open the passenger stuff and took the leaf blower to it. A lot of water but nothing obvious on the plugs. Still can’t figure out why my passenger seat warmer indicator light is on. There is no wetness under the passenger seat where that plug is.

Oh and the engine rpm’s shot through the roof but I highly doubt I went to 9k, it was def in the 6 range though

 

[kcjaz]

Oh and the engine rpm’s shot through the roof but I highly doubt I went to 9k, it was def in the 6 range though

If it was the transfer dropping into lo and trans in 6th gear, rps would be about 4200. That would seem more likely to me than the tranny just downshifting. That would still get your attention for sure and would feel like slamming on the brakes. Kinda scary. Certainly sounds like water intrusion is a probable cause.

 

[bloc]

I don’t think our transfer case can shift on the fly like that though. The grinding and such would be incredible.

 

[04UZJ100]

Can’t switch on the fly.

 

[tbisaacs]

Flashing 4lo light doesn’t always indicate a successful shift into 4lo FYI.

 

[zoned]

Yeah there’s no way it switched to low. I just put it in low and I think it would have just blown up had it tried that nonsense. It does feel lot shifted Into s2 and just stayed there for a few though and blinked the 4lo light. There’s no codes stored so I have no idea. Another weird thing is my seat warmer button light stays on even when I pull the 10a fuse for all that stuff. I praying it just dries out and goes away. I’m too ocd for that lol

 

[doru]

Water in the electrics can do lots of weird stuff. Have that investigated. Just drying it out will do no good for next time it happens.

I would not be in such a hurry to dry it out. I would first find the location of the water intrusion.

 

[customcruiser]

I get the flashing 4Lo light often - mostly after it rains. Just flashes but has never downshifted or gone into 4Lo

 

[OregonLC]

If it was the transfer dropping into lo and trans in 6th gear, rps would be about 4200. That would seem more likely to me than the tranny just downshifting. That would still get your attention for sure and would feel like slamming on the brakes. Kinda scary. Certainly sounds like water intrusion is a probable cause.

Obviously there's a lot to unpack with what happened in this scenario, however I believe 4 Lo is limited to 4th gear; both overdrives are blocked.

 

[kcjaz]

Obviously there's a lot to unpack with what happened in this scenario, however I believe 4 Lo is limited to 4th gear; both overdrives are blocked.

I believe you are right on that but wired stuff can happen with water intrusion. 4th lo would be 7100 rpm at 65 mph which is in the zip code of what the OP has said.