jacking by the differential (not fins) safe?

[yonoconozco]

so what's the consensus about jacking a car up at the differential? seems to be about 50/50 from the searches. i ran across this pelican part technical page about jacking an e36 and they say:

http://www.pelicanparts.com/BMW/techarticles/E36-Jacking_Up/E36-Jacking_Up.htm
http://www.pelicanparts.com/BMW/techarticles/E36-Jacking_Up/pic10.jpg
" If you would like to raise just the rear of the car, there are a few methods that you can use. The most common one is to lift the entire car by the bottom of the rear differential. This will not damage the differential as it is very strong at this point. An advantage to this is that you raise both sides of the car at the same time. Thus, you are only doing half the work. Place the jack under the rear differential and place a rolled up newspaper under the lifting pad of the jack. Proceed to lift the car up by the rear differential until you can place jack stands under the support points described in the previous paragraph."

i am at a loss. my jack isn't low enough to reach the crossmember on my lowered e36 so the differential is looking to be the only place to bring the rear up at once. i don't trust jacking up one side, put it on stands and then jacking up the other. :help

[ken_vs_ryu]

Do you have ramps? I reversed onto ramps and then jacked on the crossmember.

[yonoconozco]

i've had ramps and drove off them on my old integra before, slight underbody damage but was scary as hell :stickoutt . i think it was because one of the ramps slipped or moved. should have used something to brace them on the back. maybe i should give them another try but that little ridge still scares me. i'm afraid i'll drive right over it.

[BenH]

I bought the aluminum jack from Sears for $190 on sale. It's a popular choice among track junkies for very obvious reasons. I see so many of them at the paddock I often wondered if I should put my name on mine. I would use a square block of wood (2x4) rather than newspaper to clear the diff fins. One thing is for sure, use a flash light to constantly keep an eye on it when you jack it up. Once it's up, use stands and place them by the factory jacking points by the rocker panels.

Shiny side up.

[yonoconozco]

stician are you a proponent of using the differential housing to jack up the car? this is so frustrating because i can't find solid evidence that one method is better than the other, jacking crossmember or differential housing. a lot of people are against it probably because they read or heard from others, so i would say it's all speculation. i need to get a low profile jack. i've been using a cheap one that's too tall from pepboys. $190 is out of my budget :jedicryin

[Randy Forbes]

I jack the rearend up by placing the jack under the differential; I put a short piece of 2x4 between the jack pad and bottom of the differential so the jack doesn't touch the low hanging fins on the OEM ///M covers.

[bcausseaux]

All I know is if it is good enough for Randy, then it is good enough for me :D

[yonoconozco]

All I know is if it is good enough for Randy, then it is good enough for me :D

why is randy a bmw technician or something? i guess i will try jacking the diff with a piece of plywood on top.

[mz.368]

i guess i will try jacking the diff with a piece of plywood on top.

:confused I would think the ole newspaper trick would give you more protection than a piece of plywood....get a 2x4 and cut it into smaller blocks, they come in handy all the time in the garage. Cheap insurance.

[Blacksport350]

+1 for jacking by the diff with a block of wood. :buttrock

[yonoconozco]

so i cross-posted this on another board and it's sparking a lot of debate. are there any mechanical engineers here? People who have been jacking from the differential have been doing so for years though but a lot of talk about it being dangerous like broken ears, torn bushings really scares me.

one guy says:
"I always use the diff. It is very strong. Which do you think is more stressfull on the diff, dumping the clutch to run 1.7 60ft time or using it as a jacking point??
My friend who is a BMW tech reccommends using the diff."

then another two who are opposed to jacking the diff says:
"Nope, the diff receives twisting forces when you drop the clutch, completely different than this. You're pushing the diff up and hoping it supports the whole weight of your car with this stupid method."

"As to needing concrete evidence? come on man.. just think about it. Woul you rather jack something up that is attached to the subframe, or the subframe itself?!
And Ive known people to break the ears off by jacking from the diff... caus someone bought my stock diff cover b/c they did just that :nono"

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[6i9]

I've only done it once, but I did it as Randy said