Here are some of the most likely culprits:
* Differential Problems: This is a very common cause of roaring noises from the rear of a vehicle. Worn bearings, damaged gears, or low differential fluid can all create a roaring sound, often worse under acceleration or when turning. This is a serious issue that needs professional attention.
* Wheel Bearings: Worn wheel bearings can also produce a roaring sound, often changing in pitch with speed. They'll usually make more noise at higher speeds. This is another area requiring professional diagnosis and repair.
* Exhaust System Leak: A significant leak in the exhaust system, especially near the rear muffler or tailpipe, can create a roaring or rumbling sound, particularly at higher RPMs. This is usually easier to pinpoint visually or by listening carefully for the location of the leak.
* Tires: While less likely to create a *roaring* sound, severely worn or improperly inflated tires can make a humming or growling noise. Check the tread depth and tire pressure.
* Transfer Case (if 4WD): Problems in the transfer case, particularly worn components, can generate noise that might sound like a roar, especially in 4WD operation.
* Driveshaft: A damaged or worn driveshaft could contribute to a roaring sound, particularly if it's related to the U-joints.
To help narrow down the possibilities, consider these questions:
* When does the noise occur? (acceleration, deceleration, turning, constant speed)
* What is the pitch of the noise? (high-pitched whine, low-pitched rumble, etc.)
* Does the noise change with speed?
* Is the noise consistent, or does it come and go?
* Is it louder when turning? (points to differential or wheel bearings)
* Is it louder when accelerating? (points to differential, driveshaft, or transmission)
Recommendation: Don't ignore the roaring noise. It's crucial to have a mechanic inspect your Suburban to pinpoint the exact cause and prevent further damage. Ignoring the issue could lead to a more expensive repair later, or even a breakdown on the road. A professional inspection is the best way to diagnose this issue accurately and safely.
