I've taken my K5 steering wheel off for some turn signal and lock cylinder servicing and found that the splined end of the steering shaft and the corresponding part on the steering wheel itself were both somewhat rusty. I figure that just a little bit of quality lube on the parts before reinstall would protect against corrosion, sticking and excessive wear, but is there any reason - security related or otherwise - to advice against such a thing? I wouldn't think so; I'd still be torquing the shaft nut to specification and even reinstall the (to my mind not really necessary) retainer clip, but I'd rather be safe than sorry when it comes to steering by asking around for definite affirmation prior to undertaking anything not covered in the service manual.