dumb ring and pinion question about regearing

[5spdman]

Hey there folks! This may be a stupid question, and one that has been answered before, but scouring these forums and the other interwebs for the last few hours has not given me any answers to the questions that are for some reason keeping me up at night.......

If I were to upgrade the gears in my 91 XLT (3.55:1 ratio) to 3.73 or 4.10, and just wanted to pull diffs at a junkyard to keep cost on my end lower, would I have to pull and replace the pinion as well, or will it all just be "pain free", as in just pull the ring/diffs from the yard and swap them into my current axles? I'm planning on at least 31's after a build-up, so I'm leaning towards 4.10 gears...also, the diffs will be cheaper than getting different axles at the local U-Pick-It ($63 per diff vs. $118 for rear axle, $153 for front TTB.) Or would it just be better to replace the axle due to the actual price for a diff swap being more than the axle itself due to replacing bearings, the crush sleeve, spacers, etc, etc?

I highly doubt pain free will be the answers I get, not that I'm really worried about it, but figured I'd weigh all my options first and try to understand differential gearing more than I already do from all your wonderful insights and collective knowledge. I'm kind of thinking "swap axles" at least with the 8.8 to upgrade to disc rear, but undecided at this point. It will be a while before all of this goes down, so I have some time....

Please be gentle haha!

 

[PopRichie77]

It's not pain free, a new crush sleeve is needed for the pinion, also special tool is needed to set the pinion depth and then the ring gear has to be set for clearance. Best have it done by a shop that can do it correctly if you don't there will be damage. Change the whole carrier, but you should still check inside that everything looks ok.

 

[5spdman]

I knew that the crush sleeve was not reusable, and I have/have access to a dial indicator to set backlash, dial-torque wrench for pinion pre-load, all that jazz....I guess my real question (in simpler form and not so many words) is:

Will a 4.10 diff (or 3.73) work with a pinion from a 3.55 diff so I don't have to mess with that part of it?

I've never counted teeth on rings an pinions with different ratios to know if the ratio comes just from the number of teeth on the ring........................and now that I've typed all that out, I think I just answered my own question with "no."

 

[shucker1]

The ring and pinion gear are always cut as a "Set" therefore they should stay together for their entire lives.

Even if you do get a new ring gear set up correctly, chances are it going to make noise.

 

[5spdman]

The ring and pinion gear are always cut as a "Set" therefore they should stay together for their entire lives.

Even if you do get a new ring gear set up correctly, chances are it going to make noise.

That helps answer my question!

(Not that yours didn't help PopRichie77)

 

[jd4242]

Its definitely worth the extra cost to buy and swap the whole new disc brake axle.plus you get disc and save a TON of time.go 4.10 if you can find it.