Jacking car up in park - PeachParts Mercedes-Benz Forum

JHZR2 · #1 03-06-2010, 11:46 PM

Hello,

Before starting my effort to do oil cooler lines and other fun parts, I jacked the whole front end of my car up a bit, with the AT in park. Might I have damaged anything? What is the worst that could happen?

The car sat on two wheels and two jackstands for the last number of weeks. Now I get a funny noise (sounds like a baseball card in a bicycle wheel), and a slight vibration at 30-40MPH. Doesnt go away taking the car out of gear.

Never happened before, and the last use was an XC trip, where the car was flawless the whole trip.

Jeremy5848 · #2 03-06-2010, 11:52 PM

Which car?

Jacking up the front of the car with the AT in Park should not have damaged anything. I've done it many times with many different cars, Benz and non-Benz. Might you have a worn-out motor mount that sagged while the car was at an angle? That might cause something in the power train to rub on the chassis.

JHZR2 · #3 03-06-2010, 11:58 PM

82 300CD. Not a moor mount, as I just changed them. Perhaps another mount someplace in the line.

It is speed specific, and not reliant on the engine being in gear or whatnot.

Im wondering if it is just flatspotting due to sitting for weeks on two wheels...

Diesel911 · #4 03-06-2010, 11:58 PM

Besure to block the Wheels.

JHZR2 · #5 03-07-2010, 12:13 AM

I did

pawoSD · #6 03-07-2010, 12:38 AM

Could be the driveshaft carrier bearing or one of the rear CV axles....

rhodes2010 · #7 03-07-2010, 12:49 AM

It is frustrating when one event or repair or thing makes us
think we damaged something else.

And too often , especially on our vintage cars, it is just a coincidence.

I agree that sitting on stands for a few weeks or jacking car with trans in park
is no big deal.

Also think that you should check rear axles.

Jack up the rear, put it in neutral, spin the wheels and listen and feel
for something binding or clunking.

Maybe with the windows down and a helper you can listen carefully and see if your
bicycle card in the spokes noise is coming from the front, rear, left , or right.

Do you feel anything in the shifter when this noise happens ?

JHZR2 · #8 03-07-2010, 09:01 AM

Nothing felt in the shifter or steering wheel. Nothing changes when it happens with the shifter in D or in neutral. Speed is the only factor - nothing up to about 25, then it builds, from 30-40 it is the most, then by over 45, it smooths perfectly, no noise, no rumbling.

vstech · #9 03-07-2010, 09:29 AM

speed dependent only, could be tires, axles, diff or diff mounts, drive shaft flex joints, shocks, brakes, etc...
let the hunt begin!

JB3 · #10 03-07-2010, 10:18 AM

did you move your fan shroud when you put the cooler lines in? maybe the shroud is not seated properly, and the fan is kissing it, maybe even just slightly under load when the engine twists a little.

I agree that sitting in park on two wheels should not have damaged it, I guess theoretically you could have bent the parking pawl, but I doubt it. Heres a pic of a parking pawl that shows how unlikely that is-

I found this on the internet, so its not a MB, but shows generally the setup of a parking pawl pretty clearly-

Junkman · #11 03-07-2010, 10:55 AM

Got a friend (ly shop) with a dino? You could put it on rollers & listen. Catch them on the weekend when they're playing.

JHZR2 · #12 03-07-2010, 02:10 PM

Quote:

Originally Posted by dropnosky

did you move your fan shroud when you put the cooler lines in? maybe the shroud is not seated properly, and the fan is kissing it, maybe even just slightly under load when the engine twists a little.

I agree that sitting in park on two wheels should not have damaged it, I guess theoretically you could have bent the parking pawl, but I doubt it. Heres a pic of a parking pawl that shows how unlikely that is-

I found this on the internet, so its not a MB, but shows generally the setup of a parking pawl pretty clearly-

I did move the fan shroud, put it back so that everything was aligned.

Definitely will have a look though. Thanks for the idea!

cmbdiesel · #13 03-07-2010, 08:21 PM

Stone stuck in the tire or hub cap?? your description of the noise effectively eliminates anything in the drive train, leaving you with tires, wheels, brakes, hub and bearings...

cmbdiesel · #14 03-07-2010, 08:22 PM

Quote:

Originally Posted by dropnosky

did you move your fan shroud when you put the cooler lines in? maybe the shroud is not seated properly, and the fan is kissing it, maybe even just slightly under load when the engine twists a little.

I agree that sitting in park on two wheels should not have damaged it, I guess theoretically you could have bent the parking pawl, but I doubt it. Heres a pic of a parking pawl that shows how unlikely that is-

I found this on the internet, so its not a MB, but shows generally the setup of a parking pawl pretty clearly-

says the noise is the same under load or coasting...

JB3 · #15 03-07-2010, 08:33 PM

so he did, sorry! so much for that theory

Look for tools as well stuck on a moving component, I found a screwdriver jammed in the caliper of a minivan several hundred miles after it had gone in for brake service. Complaint was "scraping noise". The handle was sanding against the rim

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