Squeal/whine while under load

Joined
Jan 19, 2014
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264
Location
Detroit
Hey all,

I’m working on a 95 and I’m having some difficulty diagnosing an engine noise.

Relevant Recent service:
Plugs, wires, coil
Filters/oil change
Belts, idler pulley
Fan clutch

So here’s the problem:

When I’m driving the truck and I accelerate and get the engine over ~2000rpm, a nasty whine /squeal happens and will go away once engine speed drops. What’s strange is I can’t replicate it while stationary. It’s high pitched and I thought it was maybe the idler pulley but I replaced that to no avail. I’m leaning towards the alternator currently but I wouldn’t think that would make noise that seems to be dependent on engine load. I don’t think it’s the power steering pump either since I have to steer at severe angles to get out of the garage.
I’ve tried changing the tension on the bets to see if that changes it too and nothing. Before I pull the trigger on the alternator, can you guys think of anything else that I should check? Thanks

Also:
Both axles rebuilt
Drive shafts & joints greased
 
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Apr 14, 2016
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Oregon
Did you remove the belt and spin the alternator and wiggle it to check for slop?

What about the water pump?

I don't see any reason why anything driven by the belts would *only* make racket when the engine is under load, though.

When you tested it while stationary, was it otherwise in the same operating state as when you hear the noise? Like, was engine warmed up similarly?
 

Tachycardic

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Is the whine still there at speed? I have a whine from between 55-65mph and the noise actually came from the front diff.
 
Joined
Jan 19, 2014
Messages
264
Location
Detroit
Did you remove the belt and spin the alternator and wiggle it to check for slop?

What about the water pump?

I don't see any reason why anything driven by the belts would *only* make racket when the engine is under load, though.

When you tested it while stationary, was it otherwise in the same operating state as when you hear the noise? Like, was engine warmed up similarly?
The alternator didn’t feel sloppy when I replaced the belt a little while ago but that may have changed, I can check again.

When it was stationary, the engine was warmed up and the same otherwise. I tried in the street with the trans in drive and foot firmly on the brake but I couldn’t get the noise back.


Is the whine still there at speed? I have a whine from between 55-65mph and the noise actually came from the front diff.
It’s still there at cruising speed. Seems like it’s engine speed related and only when under some sort of load. It won’t do it in park.

I’m honestly befuddled. I haven’t heard a whine/squeal like this. I can try to record it this afternoon maybe
 
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Dec 10, 2007
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8,791
Can you get a video of the noise?
 
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Nov 9, 2012
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Olathe, KS, USA
What belts did you install?

Brand and part number if possible.

Did you route the belts PROPERLY so the idler is inside the belts?
 
Joined
Jan 19, 2014
Messages
264
Location
Detroit
What belts did you install?

Brand and part number if possible.

Did you route the belts PROPERLY so the idler is inside the belts?
Continental v belts. I don’t recall the part number.

Yes, belts are routed properly.
How sure are you that it's even coming from the engine compartment?
100%

I’ll try to get a video, I’m replacing the tie rod ends right now
 
Joined
Nov 9, 2012
Messages
12,983
Location
Olathe, KS, USA
Continental v belts. I don’t recall the part number.

Yes, belts are routed properly.

100%

I’ll try to get a video, I’m replacing the tie rod ends right now
Are they ribbed on the inside?
 

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