How to Troubleshoot "Jumpy" Rear End

Question

The Vehicle

1994 Nissan Sentra, GA16DE engine, automatic transmission, 326k

Recent Maintenance

• motor oil change (last 2 weeks)
• replaced cracked rear wheel spacers (~5 months ago)

Symptoms

How does it sound: The car started having a low-pitch rattling sound coming form the rear while driving. It's not continuous, it seems to be related to hitting bumps and potholes. It's not a high-pitch noise like a loose exhaust clamp or a loose exhaust heat shield (I've had both of those before), it's a low-pitch noise, like something stiff and thick is loose. I don't feel any vibration, I just hear the sound.

How does it drive: Well, I could be imagining things, but it feels like the car isn't cornering to the right like it used to. Could be that now that winter weather is breaking I'm taking corners too quickly and these winter tires can't handle it, could be the front-left is a bit low on pressure (doubtful, I checked it recently). Could it be the rear anti-sway bar snapped or got loose somehow?

Answer 1

I rechecked the tire pressures, they were fine, so I raised the rear of the vehicle and did a visual inspection. I didn't see anything odd or out of place.

I started tugging at things. First the anti-sway bar in different spots, it's really on there, and it seems to still be one solid piece. Then I tugged at the exhaust pipe, it's moving around like it's supposed to, but that too is still one solid continuous piece. I checked the attachment points for the exhaust, they are firm and secure.

I next checked the rear suspension. The rubber boots are ripped and mostly gone, that can't be good, so I tested the suspension for shock dampening, using the world famous "Knee Test." See results below.

Knee Test