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-   -   TH-400 "whirring noise" at med. RPM's (http://www.hotrodders.com/forum/th-400-whirring-noise-med-rpms-86759.html)

NASCAR314 04-12-2006 08:38 PM

TH-400 "whirring noise" at med. RPM's
 
Stock 1973 Chevrolet Turbo 400 transmission in my Street Rod:

It has developed a noise present at acceleration from about 1,000 rpm's up to about 3,000 rpm's. Worse under load. Less in nuetral. Sounds like a "whirring" noise. Not a Grinding, scraping, or skreching noise.

It is not the water pump, alternator, belts, cooling fans, or timing chain (checked those). Seems to be originating from the bellhousing area, or flywheel area.

Trans. seems to operate just fine, shifts properly, pulls strong, ect..., Transmission fluid is full, and looks and smells like new.

Almost sounds like a "Blower Belt" on a Blown motor from inside the car. Or those "noisy" timing gears. It does change pitch with increase in RPM's

This noise seems worse during colder weather, and then dissapates somewhat as engine / trans. warms up.

Any idea's? could it be the transmission fluid pump? torque convertor?

curtis73 04-12-2006 10:24 PM

400's governors are known for whining. If its not excessive its fine, but if it suddenly cropped up and makes more than average noise it might be wise to pull it. Its easy to do. Its held in with a little spring wire over a round cap.

Crosley 04-12-2006 10:24 PM

Quote:

Originally Posted by NASCAR314
Stock 1973 Chevrolet Turbo 400 transmission in my Street Rod:

It has developed a noise present at acceleration from about 1,000 rpm's up to about 3,000 rpm's. Worse under load. Less in nuetral. Sounds like a "whirring" noise. Not a Grinding, scraping, or skreching noise.

It is not the water pump, alternator, belts, cooling fans, or timing chain (checked those). Seems to be originating from the bellhousing area, or flywheel area.

Trans. seems to operate just fine, shifts properly, pulls strong, ect..., Transmission fluid is full, and looks and smells like new.

Almost sounds like a "Blower Belt" on a Blown motor from inside the car. Or those "noisy" timing gears. It does change pitch with increase in RPM's

This noise seems worse during colder weather, and then dissapates somewhat as engine / trans. warms up.

Any idea's? could it be the transmission fluid pump? torque convertor?



sounds like the pump is working hard to pull fluid in.

I'd drop the pan and change the filter if that has not been done for a while


:cool:

NASCAR314 04-13-2006 03:08 PM

The noise is definatly more than "average".

Fluid and filter was changed about 1 year / 2,000 miles ago. Perhaps I screwed that up when I did it then? Not sure how I could screw it up. Pretty easy to pull pan on this car, so I may do it just for a check.

Where is the Governor located? is it inside the pan area (something to do when pan is off), or on the exterior case?

Crosley 04-13-2006 08:06 PM

Quote:

Originally Posted by NASCAR314
The noise is definatly more than "average".

Fluid and filter was changed about 1 year / 2,000 miles ago. Perhaps I screwed that up when I did it then? Not sure how I could screw it up. Pretty easy to pull pan on this car, so I may do it just for a check.

Where is the Governor located? is it inside the pan area (something to do when pan is off), or on the exterior case?


I've never heard of a governor causing a whine.... the gov is under a 4 bolt square cover near the rear tail of the tranny case

NASCAR314 04-14-2006 09:43 PM

Could the "pump" itshelf be going bad?

Last year, (2,000 miles ago) I replaced the pump "O-ring" and gasket, along with front and rear seals, ect.., to reduce fluid leakage. It did reduce fluid leakage.

IanRiordan 04-15-2006 11:22 PM

You may have damaged the drive lugs on the converter or the pump gear when installing it. I'm with Crossley, every t400 I heard whine had a blocked filter. Filter quality could be an issue.

NASCAR314 04-19-2006 08:33 PM

Filter change fixes problem (for now!)
 
I changed the filter and fluid out, car runs great right now, very quite, shifts fine, ect...,

Filter Quality? is there any preferred brand, or type to use?

Now I wonder how long before this filter clogs up? And WHY?

Thanks for the replies,
-Tom

Crosley 04-19-2006 08:40 PM

Quote:

Originally Posted by NASCAR314
I changed the filter and fluid out, car runs great right now, very quite, shifts fine, ect...,

Filter Quality? is there any preferred brand, or type to use?

Now I wonder how long before this filter clogs up? And WHY?

Thanks for the replies,
-Tom


rip the filter open and see what is inside.

IanRiordan 04-20-2006 03:58 AM

Hey crossley I do that with trout but I doubt direct clutches are good bait.

Crosley 04-20-2006 08:07 PM

Quote:

Originally Posted by IanRiordan
Hey crossley I do that with trout but I doubt direct clutches are good bait.

I am real happy for you.



Answer to problem has been provided , tranny is repaired..


thread is closed.


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