Jacking under diff question.

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1998_K1500_Sub

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I wonder if they mean 'center' in the fore and aft direction also?

A floor jack as illustrated would only contact the differential at it lowest point, i.e., that being directly below the cover, in the center. That's the lifting point. That's how I've done it for years, but I too have questioned whether it was wise to jack there or simply "that's what people do"... so I turned to the service manual long ago for an answer.

FWIW, here's the three-page section from the service manual showing all the jacking points on the vehicle, with text and illustrations.
 

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1998_K1500_Sub

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It's a good idea to block the front wheels as well.

I don't disagree. But...

With bottle jacks (in particular), holding one end of the vehicle fixed (with blocks or simply in Park) with increasing jack height tends to pull the jack over, causing a "topple" concern exacerbated by the bottle jack's small foot print (noting earlier comments from @618 Syndicate et al.).

I think "blocks", or leaving in Park, is something to consider on a case-by-case basis, along with the jacking method.
 

AuroraGirl

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Lifting by the differential shouldnt take much to get the wheels off the ground. how big a bottle jack we talking, they can only go so high in their respective size categories
 

Pinger

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A 5 ton bottle jack - chosen as it would fit under the diff....
I did lift it there a couple of weeks ago (cover still on) and no problem. Just a bit concerned in case the cover contributes to the strength as I intend lifting with it removed. Only enough to get the wheels off and I'll likely do it a side at a time.

Front wheels will be chocked as that's all there is to hold it with with the rear wheels off the deck.
 

618 Syndicate

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I think "blocks", or leaving in Park, is something to consider on a case-by-case basis, along with the jacking method.
It is important to note that leaving a 2wd in Park while lifting the rear axle off the ground does not secure it in any way.
 

1998_K1500_Sub

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It is important to note that leaving a 2wd in Park while lifting the rear axle off the ground does not secure it in any way.

Yes, lifting even one wheel of the rear will enable the vehicle to roll.

As obvious as this is to probably everyone here, I for one have had it happen to me "by surprise".
 
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454cid

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Front wheels will be chocked as that's all there is to hold it with with the rear wheels off the deck.

Do that AFTER you've jacked it up. If you do it before you risk the the truck falling off the jack. Floor jacks can roll, bottle jacks can not, and therefor can't adjust to the change in horizontal distance as the truck goes up.
 
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