the gear shifter on my 93 sentra automatic gets very hard to move into park(but not all the time-no telling when) Also, sometimes I have to sart it in neutral because it won't click in park. Tried wd 40 on inside mechanism which provides only a temporary fix. Any way to get lube grease into the housing? What else can be done for both problems? Is this an expensive job to have fixed in the shop? Supposing I just live with it? This car's too old to put money into.