I am posting here because you are probably the only ones with good tech info on Spicer box's.
I am running an F550 with a 7.3L the overdrive ratio is .71 but with 4.88s it is revving at 2500 rpm at 65 mph. when lightly loaded I would like to be able to run at 70-75 and unloaded 80 mph but to do that I need to lower the rpms. I do like the 4.88s for pulling heavy so I thought an aux box would be a good idea.
Can a spicer aux box handle high speeds like 80 mph? I was looking at the 7041 with a .83 ratio so combined it goes down to .59
Can I rebuild them or do I just have to find a good unit?
Thanks in advance for the help.