98 Suburban - MUCH noise between 55-68 mph

**bboyd** · 03-10-2007, 11:59 AM

I have a 98 Suburban, 4WD, 5.9 V8. approx 118K miles. I love the truck, but when accelerating between 55 and 68 mph there is a LOT of noise from the vehicle in the cabin. When I get past 70, the noise goes away and also if I let off the gas the noise continues for about 3 seconds and then stops (regardless of MPH).

Any ideas are greatly appreciated. One garage told me that my Kelly tires could be causing this as they were wearing unevenly...

**L0sts0ul** · 03-10-2007, 03:15 PM

what rpm range? could be lifters or an imbalance in motor.....

**84fiero123** · 03-10-2007, 09:10 PM

Originally Posted by bboyd

I have a 98 Suburban, 4WD, 5.9 V8. approx 118K miles. I love the truck, but when accelerating between 55 and 68 mph there is a LOT of noise from the vehicle in the cabin. When I get past 70, the noise goes away and also if I let off the gas the noise continues for about 3 seconds and then stops (regardless of MPH).

Any ideas are greatly appreciated. One garage told me that my Kelly tires could be causing this as they were wearing unevenly...

Crank shaft.

I hope I'm wrong.

**GaryL** · 03-12-2007, 10:22 AM

What kind of noise is it, a whine, a rattle or what? Does it include any vibrations?

**bboyd** · 03-27-2007, 11:52 PM

There is definitely some vibration. The noise sounds like really loud road noise, and goes away when I left off the accelerator or accelerate over 70/below 58.

If it is the crankshaft as one of the other posters said, what does that involve for estimated repair costs?

**L0sts0ul** · 03-27-2007, 11:54 PM

Originally Posted by bboyd

There is definitely some vibration. The noise sounds like really loud road noise, and goes away when I left off the accelerator or accelerate over 70/below 58.

If it is the crankshaft as one of the other posters said, what does that involve for estimated repair costs?

if its the crank your are looking at a complete rebuild... really no other way.

**bboyd** · 03-27-2007, 11:59 PM

Is it possible that this could be caused by bad shocks? I've changed the front ones since purchasing the truck, but don't know if the back ones have ever been touched...

**MrShorty** · 03-28-2007, 12:07 AM

One of the first steps in diagnosing noises is to try and determine if it's engine or drivetrain related. You say the noise seems most prevalent between 55 and 68 mph. Assuming that's in 4th gear, the next thing to do would be to put the transmission in D (so it won't shift into 4th) and see if the noise occurs at the same vehicle speed or at the same engine speed (a slower vehicle speed). If the noise seems more related to engine speed, then start looking at engine related things (fan clutch, misfire, exhaust noise, etc.). If it seems more related to vehicle speed, then check things in the rest of the drivetrain (u-joints, suspension, tires, etc.).

**Steve** · 03-28-2007, 12:17 AM

It's hard to say w/o hearing the noise. I've had speed-related noises be everything from out-of-balance wheels to ... yes a damaged crank in a 350.

Shorty is right, definately try to rule out the tranny. That speed range could be when you shift into 4th gear and you may have a bad 4th. Try that first.

Is the noise louder with the windows down? Do you feel vibration, espectially anything coming up through the brakes or the steering column?