Did you remove the small dust shield from the hubs and the rubber ring from the axles?
With the 91 ls intermediate shaft you should be running the 90-93 teg axles.
Could also be a bad diff or any number of things.
__________________
Don't bother giving me "rep", I won't return it and I think it is stupid.
Gracie Barra Clearwater
Gyms in Clearwater, St. Pete and Port Richey
pm me if you are interested in trying a free class at any of the gyms.