Could dirt prevent my tranny from shifting into 5th? on 1998 Dodge Ram 2500

My hubby decided to drive our 1998 Dodge ram 2500 diesel through a very large mud hole and got us stuck for about an hour. We spent the whole day draining and topping up and draining the fluid and eventually took it to the mechanics for a full flush. It works much better but still seems to lag a bit and hasn't been shifting into 5th. What can I do about this? A friend said this truck doesn't have a 5th gear but a sensor instead, but that sounds strange to me. Can anyone help?

by in Forestville, MI on August 19, 2013
1 answer 2 comments
ANSWER by on August 20, 2013
does it set a ck engine lightor set any codes?
COMMENT by on August 20, 2013
N o check engine light but haven't tried the codes yet. A friend said it could be the solenoid, does that make sense?
COMMENT by on August 21, 2013
it could but will usually set a code for it.