Speedometer / #1 Vehicle Speed Sensor Issues

[XtboX]

Hey guys,

I have an Australian delivered (RHD) '93 LS400. We had a fairly bad storm here a couple of weeks ago where I drove through several floods. My speedo worked fine till later that night when it completely died and started flashing the O/D light. I checked the error codes and it came up with a code 42 indicating a fault with the #1 VSS.

Thinking it may have been fluid ingress in the sensor, I cleaned the sensor and the contacts which did not fix the problem. Even after replacing the sensor, I am still experiencing the same issue. I tried turning the driven gear on the VSS with the ignition on and the speedo moves, hence it would appear that the gear is not being engaged by the driveshaft.

I rang my local Lexus dealership and one of the service techs there told me that the gear on the shaft in the extension housing could be stripped. Can water ingress possibly cause a gear to be stripped? Is there a correct or incorrect way of installing the VSS? The hole where the VSS shaft goes into is fairly tight, and to insert the VSS I've had to wiggle/rotate the VSS for it to fit in. Could this cause the gears to not engage?

Also, could someone provide some instructions on removing the extension housing to inspect the gears?

Any help would be much appreciated, thanks!