[dan the man]

Good morning folks!! I got into some water this morning on my way to work. Not much maybe 8-10” deep but it was on I10 on the inside lane and I was slowing down but I was probably going 30mph when I hit it. After I got through it my speedometer was all over the place and my A727 wouldn’t go into OD. Do y’all think the speed sensor got wet? Would that affect the OD? Thanks for whatever info y’all can give me

 

[mcjc21]

What year is your truck? It’s a good possibility you got water in the connector. It should by the sensor in the top of the diff. There is a connector on the frame rail above the axle also if I remember correctly.

 

[dan the man]

It’s a 1993 D350. It seems to have dried out and is working properly now but with all the high water we get here in Houston I want to try to keep it from happening again. Maybe heat shrink the connection?

 

[Ruderunner]

First gen trucks have the speed sensor on the transmission, the one on the rear axle is abs only.

That said, it sounds like a wet sensor or connector is a likely culprit. Also look at the wires going over the transmission, might be rubbing on the case.

 

[dan the man]

Thanks brother. I got a few minor electrical issues I need to address so this falls right in. Lol my ABS and brake warning lights are on and my blower motor stays on when the key is out. I replaced the ignition switch but that didn’t fix anything. I was told about some wiring that goes to the transmission from the ignition switch to indicate the transmission is in park and that could be causing the blower issue but I haven’t had a chance to dig too

 

[Ruderunner]

Transmission and ignition are only connected in relation to the starter. There's a switch on the transmission that keeps you from cranking the engine unless the transmission is in park or neutral.

The blower problem is not related to that.

Sounds like you might have PO disease. Get yourself a wiring diagram, you're going to need it.

 

[dan the man]

Thanks for the info. I downloaded a diagram and when I get a chance I’ll start digging into it. I was skeptical about the blower motor being related to anything on the transmission but I figured anything was possible on a 25 year old system. I’m probably going to regret this but what is PO disease?