If you like the Ruger, keep it.... If you aren't crazy about it anyway, sell it.
I buy/sell/trade all the time, but I've learned NEVER to sell a pistol you like for something you THINK you'll like better, or that you THINK will be a better choice... Besides, you won't get a lot of $$$ for a used Ruger revolver anyway... certainly not near what you paid for it.
Now, having said that... I'm NOT voting that you keep the revolver as your truck gun. I'm just voting to keep the revolver, period.
Save up a few $$$ and buy a 9mm semi-auto too. There are quite a few excellent choices for under $300. Call it "her" gun, if that helps you to get executive approval for the purchase...
You could easily use the 9mm in the truck if you want, because there's absolutely NOTHING wrong carrying a semi with one in the chamber...
I also laugh when someone suggests that "the slide on a semi can be pushed back and out of battery". Has that EVER happened to ANYONE in a stressful situation???
A revolver can be made unfireable by grabbing the cylinder and holding firmly... What's the difference?
I've almost always used a semi as my "truck gun", and it has NEVER suffered any dirt related malfunctions. Some guys seem to think that "truck gun" means you keep it in the floorboard or under the front seat, just sliding around without a holster or any sort of protection/restraining device.
I always keep mine high and dry, and in some sort of holster or other protective covering.