91 grand prix wont start

i have a 91 grandprix. it has a 3.1litre motor.i had the tranny replaced and now it wont start. when i turn the key on to start it nothing happens . all the power accesories work . also when i try to start it all the gauges such as engine temp the needle pegs out. when u let the key go back to accesory the gauges read right. i was thnking this might be the cause of a bad ground ? id really apreciat some help pls

I would double check all battery cables for corroded/dirty connections, as well as check to be sure the ground straps were hooked back up after the trans was swapped.

I agree with Rich, but would like to add....

Take a look at the two ignition wires with fuse links in them that hook up to the starter. Cant miss them, I think they are going to be Red and are quite thick. Make sure they are present and tightly hooked up.

thanks guys for ur imput. I did figure out why it wouldnt start. I found the neutal/reverse switch wasnt set right. loosened the 2 holding bolts adjusted it to spec and now it starts right up. thanks again for ur help .