hello all i am a new to the site and am having problems with my 03 2500hd with the 8.1/allison. last week i turned the key and all the lights and guages came on... but wheni proceeded to start the truck i got nothing.. so i crawled underneath and jumped the selenoid and it started right up.. so i took it to my buddies shop and he replaced the starter and selenoid and the starter switch and that did absolutely nothing...
right now i am turning the key on and going under the hood and jumping the starter relay in order to start it..

Does anyone have any ideas

 

hey check to see if the start relay under the hood should be on the driver side is good

 

Bad or loose battery cable bolts can cause the exact same syptoms as a bad starter. If they are tight remove them from the battery and look at the cable where it touches the battery. Also inspect the threads.

 

well guys its fixed... the connectors to the nsbu switch on the allison were bad... thanks for the help