Is it safe to put the car in gear with the rear on jack stands

[AnthonyA1234]

Trying to find a rattle I’ve been getting ever since I changed my shocks and springs. I’ve got the rear end on jack stands right now with the stands on the rear axle so that the dif isn’t floating. Is it safe to put it in gear and give it some gas to see if I hear the rattle?

 

[General karthief]

Sure just block the front wheels good and make sure you don't get any clothing or hair near any rotating parts/pieces.
Can't afford to loose any members.

 

[AnthonyA1234]

Sure just block the front wheels good and make sure you don't get any clothing or hair near any rotating parts/pieces.
Can't afford to loose any members.

Thanks!

 

[manicmechanic007]

Don't run it up much past 50mph

 

[Mustang5L5]

I’ve done it quite a few time.

Rear on stands and chock the front wheels. Have someone in the car ready to go to nuetral or kill the engine

 

[7991LXnSHO]

I’ve done it quite a few time.

Rear on stands and chock the front wheels. Have someone in the car ready to go to nuetral or kill the engine

I wondered if they were yanking my chain when they first suggested this.
Do not use HFT Jack stands.

 

[revhead347]

Yes, Chock the wheel. Running the car in gear with the rear wheels elevated is considered a necessary risk to diagnose things.

Kurt

 

[AnthonyA1234]

Did it and everything went smooth but unfortunately no rattle. I have no idea where it’s coming from

 

[General karthief]

Take a rubber hammer and wack things like the exhaust system in several places, fuel tank, make sure the spare tire and jack are secure if present, axle housing, shocks, floor pan, you may need to con a buddy to ride in the back and hunt the rattle.

 

[General karthief]

Oh, I forgot whiskey, it doesn't help find the rattle but it don't hurt.

 

[KRUISR]

When do you experience the rattle? At idle, while accelerating, decelerating, coasting, braking, hitting a bump, turning left or right or both?

 

[AnthonyA1234]

When do you experience the rattle? At idle, while accelerating, decelerating, coasting, braking, hitting a bump, turning left or right or both?

It’s when I give it gas. Another time it makes the noise is when the rpm’s get too low and the car starts to buck since my car has a X cam.

 

[AnthonyA1234]

It’s when I give it gas. Another time it makes the noise is when the rpm’s get too low and the car starts to buck since my car has a X cam.

Doesn’t have anything to do with steering or bumps just accelerating. However the fact that it does it when the car is bucking and I’m not giving it gas makes me wonder if it has something to do with when the car squats.

 

[manicmechanic007]

Chassis ears
That is what they have you use in screwell
NVH is a bitch to diag sometimes
Interrogate the rear sway bar. They used to be hollow and will crack in half where it's hard to see
A set of chassis ears used to be expensive. Not any more
Get some if you need to ( I do not own a set )
I have been doing this so long I am the chassis ears

 

[limp]

Sounds like the engine torques over, while accelerating, something moves and makes contact.... Have you checked your motor mounts... If they are bad your engine might be moving enoiugh to let items ( like the exhaust) make contact with something??

 

[AnthonyA1234]

Chassis ears
That is what they have you use in screwell
NVH is a bitch to diag sometimes
Interrogate the rear sway bar. They used to be hollow and will crack in half where it's hard to see
A set of chassis ears used to be expensive. Not any more
Get some if you need to ( I do not own a set )
I have been doing this so long I am the chassis ears

Cool I didn’t know they are tools like that. Can the wired version be used while driving? Also does that clamp have to be clamped on to exactly what’s vibrating to pick it up or can it pick it up when it’s in the vicinity of it?

 

[AnthonyA1234]

Sounds like the engine torques over, while accelerating, something moves and makes contact.... Have you checked your motor mounts... If they are bad your engine might be moving enoiugh to let items ( like the exhaust) make contact with something??

That’s possible my engine mounts are original I’ve been planning on replacing them but i don’t think they move the engine that bad. I think it’s got to be something that I touched when I was doing the suspension work since the rattle happened after that .

 

[91TwighlightGT]

Trying to find a rattle I’ve been getting ever since I changed my shocks and springs.

Hold on - before we start chasing motor mounts, let's not forget the first post of this thread. Last thing touched should be the order of operations here.


EDIT: You changed your shocks and springs - what did you change them from and to? Did you use spring isolators?

 

[AnthonyA1234]

I went from stock shocks/struts and springs to bilstein shocks/struts and H&R sport springs. I did maximum motorsports starter kit but swapped in the H&R springs over their brand springs so yes I put the poly isolators and the poly pinion snubber along with the MM camber caster plates. I also changed out the sway bar end links for energy suspension ones along with the sway bar bushings for energy suspension bushings.

I’ve gone through everything and from what I can tell everything looks good. I’ve put weight on the front and the back of the car to check if the shocks move up to see if maybe the shaft nut wasn’t tight enough but everything looked good. I also took off the front brakes and rotors last night (I didn’t touch the rear ones during the install) since my neighbor told me it sounded like the pads were rubbing something when I drove by his house. Took everything apart and there wasn’t anything stuck between the pad and rotor but I hit it with brake clean and I hit the pads with compressed air just in case. Took the car out for a ride after and it didn’t make a difference.

 

[AnthonyA1234]

Another thing I changed that I forgot to mention was the quads. Went from factory quad shocks to bilsteins and they are flipped to fit my new wider tires. The quads are pretty close to the rear shock but I think there’s just enough room and I don’t see any wear marks on the paint of either so I don’t think that’s it.