Gentleman
Can the rear end of a 1998 Mercury Grand Marquis be safely lifted with a floor jack under the differential? I went through my owners manual and also the jacking instructions under the spare tire cover and found no warnings to the contrary. The differential casting and cover have two notches at the bottom that fit my floor jack saddle. The saddle is also fitted with a thick rubber pad so differential cover damage would not be a problem. I have heard that some cars can be damaged when lifted in this area, Is this one of those cars? Thanks!

I try to avoid center-lifting due to stability issues... Why don't you jack up each side seperately and throw stands under the frame? Takes all of an extra 2 minutes.

I've done it on my Crown Vics (and my wife's Expedition) dozens of times and never had a problem.

For whatever it's worth...

I've done it as well, and it definately work, just saying I tend to avoid it because it is less stabil than jacking each side seperately. On cement this is not as big of an issue, but if your on packed dirt or something of that nature I would definately avoid center jacking.

I agree with Buck, on concrete it should be okay but on gravel or dirt or otherwise it gets pretty scary especially if both tires are off. I flattened a floor jack once with my 54 Ford, had the front jacked up with both tires off, on dirt no less. It fell over when it sank in a little, at least I wasn't under it! Guess thats why they are called FLOOR jacks!

I would TOTALLY avoid it. I raise my car on jackstands all the time. it is not recommended to jack up the car by the diff. What are you trying to do? I would jack up on the frame, then place jackstand(s) under the frame right before the frame turns up in the rear(right where you'd put the arms/pads for a lift). I just don't understand why you'd want to jack up the diff. and nothing else(unless you were adjusting ride height sensor, or tightening shock mounts/endlinks or something.....

WTF are you trying to do?

Lift up each side separately and put a jack stand under the axle. If you don't have you should get them. I'd avoid lifting by differential.

Quote:

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and put a jack stand under the axle.

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Do you think this is wise? What if you bend the housing/tubes?
Why not just jack up the frame, like a normal person?
This is why I was wondering what the ultimate goal was.......

I'm installing a swaybar and need the axle under pressure. Is that not normal?

Whoa... what's so wrong with jacking under the diff, then putting 2 stands underneath either the axle tubes or the frame rails? It's unsteady for the amount of time it's only on the jack, but once it's sitting on the stands it's fine, right?

Supporting/jacking the CAR up by the diff. or axle tubes is asking for trouble. Jack up the frame, put jackstands under the frame, and then raise/lower the rear axle/suspension ONLY using your jack. This is the standard MO. This is perfectly fine. This is why I asked you, because I thought you were talking about jacking the car up like that, which is bad IMHO..

The Ford workshop manual for 2003-5 CV's says:

"CAUTION: Under no circumstances should
the vehicle ever be lifted by the front control
arms, crossmember, rear stabilizer or differential
housing. Severe damage to the vehicle could
result."

I used the center of the differential to jack the car up also. I immediately put jackstands under the frame rails to stabilize the vehicle. I find it more convenient this way, and only lift on cement/blacktop. I've tried lifting vehicles on a dirt driveway before, way too unstable, everything kept moving around..

Well, my 2003 Ford Shop Manual clearly indicates that you can jack under the axle tubes on either side of the diff casing, but not under the diff casing. These are actually two of the six "official" jacking points, the 4 others being on the frame behind the front wheels and on the frame ahead of the rear wheels. That is printed black on white on pages 100-02-1 and beyond.

Now for the subjective: The reason why they do not want you to jack under the diff case is probably due to the risk of damaging the cover. There may be many types of diff covers, certainly many types of jack saddles, and definitely different levels of competence.

Now to the question "why would you want to do that", I would propose that "Because I want to" be considered as a valid answer. Probably the phrase "There is a safer way to do what you are trying to do" would have done.

And to the question "WTF are you trying to do", I would propose that "I am trying to find an answer to my question, within certain limits of respect" be considered a valid answer.