Need gear help for a F450
I have a few questions about changing the gears in a 08' 4x4 F450. I have a friend of mine wanting to buy one but he only wants it if the gears can be changed. It has a S110L rear end with 4:88's now. I had one guy that said they couldn't be. I was referred to a company out of CA called DD Williams Eq. They say you can put 3:73's or whatever you want in it. They told me that the front carrier may have to be changed but it really wasnt that exspensive for all the parts. Around $1300 or so. I am just trying to make SURE that everything will swap out without having to do anything crazy. Have any of you done this? Or may be able to point me in the right direction? Thanks.