Drivetrain issues

[Aceman]

Alright my aunt recently bought a 2004 Chevrolet Suburban Z71. It has the V8 in it. She recently has had some work done too it, including the left front differential housing replaced. It also was worked on for being stuck in 4 wheel drive. She was rolling down a hill in reverse and while it was still going back she switched it to drive. At the time it was in rear wheel drive and not 4x4 It now has a clunking noise coming from what we think is the rear differential. And it vibrates when cruising or accelerating in 40 mph range. There is also a squealing/whistling. What could the problem be? My dad and i suspect it could be the rear differential or axle. And it also has a lack or surge when accelerating, which we believe to be old spark plugs, what is your opinion?

 

[Matahoe]

Without a maintenance history it would be difficult to say unless I saw it in person. It sounds like you have multiple issues from before. Any issues from before or did they all happen at once? How is the engine performing in park? How does it idle and respond to throttle inputs in park?

You need to localize the issue. Break it down into subsystems and diagnose their individual performance (i.e. engine, transmission, driveline, braking system, etc.)

A good starting point is to see if the CHECK ENGINE LIGHT is on?

 

[Aceman]

Without a maintenance history it would be difficult to say unless I saw it in person. It sounds like you have multiple issues from before. Any issues from before or did they all happen at once? How is the engine performing in park? How does it idle and respond to throttle inputs in park?

You need to localize the issue. Break it down into subsystems and diagnose their individual performance (i.e. engine, transmission, driveline, braking system, etc.)

A good starting point is to see if the CHECK ENGINE LIGHT is on?

It was in that order of her messing up the 4x4 then the clanking and vibration started together. As for the engine it idles fine and there is no check engine light.

 

[Matahoe]

I would disconnect the front driveshaft to isolate the noise. This is to rule out a possible stuck in 4WD issue. This would isolate the problem from the torque converter back to the differential and wheels. Usually however a vibration at higher speeds indicates an unbalanced driveshaft or wheel. If I had to take a guess I would say you tweaked and fried the u-joints in the driveshaft. I would also inspect the rear differential gear oil for chips.

if removing the front driveshaft fixes the problem then you have a front cv axle or front differential issue.

 

[Aceman]

Alright thanks i will look into both of those this weekend.

 

[Matahoe]

Alright thanks i will look into both of those this weekend.

You are welcome friend. Keep us updated. Sounds like a good case.

 

[Aceman]

Will do