adsm08
Senior Master Grease Monkey
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Ford Technician
TRS 20th Anniversary
- Joined
- Sep 20, 2009
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- 34,623
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- Dillsburg PA
- Vehicle Year
- 1987
- Make / Model
- Ford
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- 4.0 V6
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- 4.0
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- Manual
- 2WD / 4WD
- 4WD
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- 31X10.50X15
I concede that jacking at the diff will change the stresses on the axle, but the weight to strength ratios of the axle on most trucks vs the weight of the rear of the truck makes the change in stress fairly negligible.That's may be true but not necessarily the case. Jacking the diff means the load is distributed differently. The load is pushing down on the outside of the axles while the support is in the center, which looks to bend the axle housings. I'd bet there's deflection of the axle by jacking at the diff., which the axle may be able to withstand if it's beefy enough. Actual experience is important but I'm not sure if engineering would support differential jacking.
I have had my truck airborne, come down hard, and not damaged the axle. This is a 7.5, which isn't particularly strong as axles go. I have seen a 9.75 get bent by a kid and all the old seasoned techs were standing around trying to figure out what kind of force it must have taken to do that.