Im about ready to fire up the new engine my dad and I just rebuilt and I was finishing up wiring up my Auto Meter electrical guages (Trans temp, oil pressure, water temp, and volts) I put the tranny temp sending unit in the pan with teflon tape on the threads. And now when I turn the key (just to the run posisition not to start it) the tranny temp just jumps up to 150 (I dunno whats wrong all the other guages dont do anything) but the volt meter reads like 18 (pegged out) so Im not sure what is wrong with these two brand new gagues. If someone could give me some things to go off of, the grounds all are good and everything b/c the lights work (and thoes and the ground for the guages are all connected to the same thing) and everything, so Im not sure what it could be. Thanks a lot guys.

Might want to check if the voltmeter positive lead is tied to the IGN terminal on the fuseblock. Should come on only when the key is turned to ON.

Sounds like the Volt meter doesn't have a good ground. I would also question the use of tape on the threads of a sender. Normally you can't do this as it insulates the case to chassis ground. With a tapered pipe thread you should not need more than a small amount of 'paste' to seal it up. You can test the sender 'case' to chassis ground with an ohm meter.