is this bad to do. in the manual it says so but ive seen it done before

 

I have seen it done before also and may have done it once or twice my self but i beleive the reason it being marked as bad to do is because you can bend the diff cover and make it leak. is my thinking could be wrong? just my .02

 

Every car has a owners manual, in that owners manual are the preferred jaking points. If they think you can jack it form the diff, go-ahead, but, there is a reason that the make jaking points.

That being said, i'm sure that I have jacked a car or two from the diff.

 

What the hell is a jaking point, are we talking turkeys here or rearends... and we won't even go to the form thingy.

 

As other have mentioned stay away from the cover, past that the diff is a great jacking point.

 

the reason the manual says not to is because of safety more than hurting the diff. Think about it... jacking from the center point of a car makes it a little tippy.

 

damn............thats what I get for not proof reading......

 

exactly, in the manual they are refering to when you get a flat and are using the tiny bottle jack under the seat. if you uesd that under the diff it would most certainly slip off and fall. a full sized floor jack is no problem under the diff.

 

Floor jack, fine. The little jack they give you....NO! Thats what a jacking point is, the only place it will work.
Remember the old bumper jacks they used to give you. Ahh the good old days.

 

My Dad's '83 Lincoln Town Car had one of those!

 

The reason for not jacking at the differential is that it will allow the axle tubes to sag and eventually lead to leaks where the axle tubes meet the differential.

 

Plus it always leans to one side so you gotta count the teeth on your jack stands

 

I don't agree with that reason.
I agree that it can be a safety issue. Especially if you don't block the front tires. I still do it with a floor jack though.

 

Well by your logic then, the tubes will bend the other way when the wheels are on the ground

 

It to me is more for safety. I have always jacked a car/ truck by the diff housing, never a problem. If it breaks, it must be Japanese because no truck I'd own would break over a minor thing like that.