'86 Toyota truck squeals when cold; only when driving

I just acquired this truck from my parents with an actual 50k miles.
It's a 2wd extra cab SR5. It seems fine except for an odd squeal while
driving when the engine is cold. The sound isn't subtle. It is a fairly
high-pitched whine or squeal that warbles slightly at the frequency of
the driveshaft (I'm guessing). I can change it's tone and loudness by
varying the throttle... no noise when coasting. If I start the truck
and let it warm up for ~10 minutes, it doesn't make the noise at all...
normally it takes 2 or 3 miles for it to quiet down.

Any ideas? It doesn't make sense to me. If it was a belt or something
in the engine, it should make noise even when I'm not driving it. On
the other hand I don't understand why warming up the engine would
silence the drivetrain.

Thanks...

In article <1167457132.076981.248410@a3g2000cwd.googlegroups.com>,
[email]rruffrruff@yahoo.com[/email] wrote:
[color=blue]
> I just acquired this truck from my parents with an actual 50k miles.
> It's a 2wd extra cab SR5. It seems fine except for an odd squeal while
> driving when the engine is cold. The sound isn't subtle. It is a fairly
> high-pitched whine or squeal that warbles slightly at the frequency of
> the driveshaft (I'm guessing). I can change it's tone and loudness by
> varying the throttle... no noise when coasting. If I start the truck
> and let it warm up for ~10 minutes, it doesn't make the noise at all...
> normally it takes 2 or 3 miles for it to quiet down.
>
> Any ideas? It doesn't make sense to me. If it was a belt or something
> in the engine, it should make noise even when I'm not driving it. On
> the other hand I don't understand why warming up the engine would
> silence the drivetrain.
>
> Thanks...[/color]

Belt squeel.
Try replacing the drive belts.
There are 2, they cost under $10 each.
If the belts don't fix the squeel, it can be the idler bearing on the
upper belt tensioner.

Ernie Leimkuhler wrote:[color=blue]
> Belt squeel.
> Try replacing the drive belts.
> There are 2, they cost under $10 each.
> If the belts don't fix the squeel, it can be the idler bearing on the
> upper belt tensioner.[/color]

I did increase the *tension* on the belts and it didn't help. It also
doesn't make sense to me that I'd need to be driving to make them
squeal. I can put it in D with the brake on and gun the engine, turn
the steering back and forth, and there is no noise. The truck needs to
be moving. I replaced an idler bearing on an '84 I used to have... it
wasn't sounding like this, though.

Yes, this is an automatic... forgot to mention that. Seems to shift
fine.

[email]rruffrruff@yahoo.com[/email] wrote:[color=blue]
> Ernie Leimkuhler wrote:[color=green]
>> Belt squeel.
>> Try replacing the drive belts.
>> There are 2, they cost under $10 each.
>> If the belts don't fix the squeel, it can be the idler bearing on the
>> upper belt tensioner.[/color]
>
> I did increase the *tension* on the belts and it didn't help. It also
> doesn't make sense to me that I'd need to be driving to make them
> squeal. I can put it in D with the brake on and gun the engine, turn
> the steering back and forth, and there is no noise. The truck needs to
> be moving. I replaced an idler bearing on an '84 I used to have... it
> wasn't sounding like this, though.
>
> Yes, this is an automatic... forgot to mention that. Seems to shift
> fine.[/color]

Does the squeal vary with speed, like maybe a disc brake pad?
--
Tom - Vista, CA

TOM wrote:[color=blue]
> Does the squeal vary with speed, like maybe a disc brake pad?[/color]

I can vary the sound quite noticably by varying the throttle
application, but it isn't really speed dependent... plus there is no
noise when coasting, so I don't think that could be it.