Differential Question

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Nov 4, 2008
Federal Way, WA
I will be doing some maintenance and upgrades late next month on my '71 40. One thing on the plan is a locker install in front (rear has one already). I have read where some people swap the diffs, front to rear. I'm wondering if that might be a good idea since I have anywhere from 80k to 180k miles on them (might be 280k+, who knows...)?

I am thinking this will help with gear tooth wear and increase the life span of the gears. Any thoughts or opinions on swapping them?


Yep, swap thirds. I've done that, since the front is typically less worn than the rear. However, who knows if the thirds you have are even original to the truck or in their original locations. In my case, I rebuilt both of them as I was installing ARBs, but I did swap the front to the back.

I would go through them, and adjust them if necessary, while you have them out. I have a plate (currently loaned-out, but retrievable) for holding/servicing thirds in a bench vise that you are welcome to borrow, if you like. In fact, I have dial indicators, mag mounts, in-lb torque wrench and anything else you need to set up your diffs.
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