Pump whine

TurboBob

Resident mad scientist
Staff member
Joined
May 24, 2001
I had a 10 vane kit put in my trans, GM parts, clearanced. I'm confident
in the local guy. But the pump appears to whine at high pressure. At part
throttle I never hear it, but under heavy throttle I hear it. Also it happens in
manual second. The whine changes pitch with RPM. Its more of a whine than
a buzz, almost a whistle in pitch.

I thought it was the new converter we put in at the same time.... I changed the converter
and the whine is still there. When I could reproduce it at light throttle
in manual second I became convinced it's the pump.

Bruce, Don, Lonnie...... any ideas?

Thanks!

Bob
 
hrmmm.....

If there was a burr on the slide , that would do it as vanes pass thru it ticks creating a whine. Also pump cavitation would do it too.
usually whine or buzz is PR valve moving back and forth at a rapid rate. Does this occur in manual low and reverse also? just manual 2? Hrmmm.......... Gots to think.....:)
 
Thanks for the reply,

I was using manual 2 to raise line pressure without having to use the
accelerator. I.e. I wanted to know if it was related to pressure or engine torque.

So, to me, it sounds like it's related to line pressure.

It does it in drive and OD at heavy throttle. Most noticed after the 2-3 shift due to
the RPMs being where the sound is a 'mid-tone'. (I don't have a musical ear....)
As the RPM's climb after the shift the frequency of the sound climbs as well as fading out ...

I will check tomorrow if I can get to do it in Park by raising the RPMs
and pulling the TV cable.

I'll also try Reverse....

Before the pump rebuild I had a Transtar PR valve and spring in there. Perhaps
the builder guy had a reason to change it back to a stock valve.

I'll try some if this tomorrow and let you know. I should probvably arrange to drop the pan
and regulator soon....

Regards,

Bob
(hoping it doesn't explode before I can fix it)
 
PR valve alone will not cause any problems. Hrmm, yes, let us know..:)
 
Have you ever heard a Transtar PR valve buzz/whine? I know there is a land to grind off
the stocker to stop this. I figured that the Transtar valve would be an 'improved' design that
wouldn't have a buzz/whine problem.

Drove it today, too cold to mess around under the hood. The noise is only noticable at
'higher' rpm (3000+) and is definately pressure related. Very hard to get to 3000 RPM in
reverse....

I'll try the park/neutral test tomorrow.

Bob
(Thanks for the help)
 
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