'03 wont shift into overdrive.

[4x4dually]

My bro-in-law just called and his '03 2500 auto shifter won't shift into overdrive. It runs great, goes through all the gears but won't go into OD. Any ideas on what is wrong? It ran fine last night and won't work today. It has I think about 70K miles on it and is used on the farm.

It has been raining down there for weeks (5 inches yesterday) and I'm sure he has been through a butt load of water. My guess is a connector has water in it somewhere that controls the OD. Am I right? If so, where would one start looking for the problematic connector or wire?

Thanks guys...and gals.

 

[4x4dually]

Bump bump.....

 

[sootman]

Most likely governor press. reg solenoid in valvebody. Also have two shift solenoids in there. they will go out if you look at them wrong. Ask him if it takes a second when he comes to a stop to find first. you will usually feel a bump. can also be a bad relay. Tell him to cylcle the tow haul in case something needs a little help or nudge.$.02