Quote Originally Posted by rspears View Post
That fits with what I've seen, and I think they "see" through fiberglass better than metal but I wouldn't swear to that. My GPS locator unit sends me messages almost daily that it has "...lost signal" sitting in the garage against the wall farthest from the windows, and in the metal barn it's a lost cause. I expect a long tunnel will be the same, but it's not a big deal to track by the tach if the speedometer drops out when blinded. They're drop dead accurate on speed.
I'll agree with all of that. I haven't been in a tunnel with it but if I lost am or fm radio signal then I'd expect the gps to go away also. I don't see it as a problem though.. and how often do you really watch you're speedo? Like most, you glance at it for reference once in a while. The other thing is the actual gauge can also be used with the tranny sensor and calibrated by the usual drive one mile push the button etc. etc. So, even if you change you're mind about the gps system, you can always connect it to the transmission.