The Stovebolt Site Forums The Shop Area Driveline Growl

My original three speed was rebuilt at a shop in Corona, CA 'cause it was popping out of high gear going downhill. Charged me 600.00 for the 'reman' transmission with a one year warranty, but it sometimes tends to gall during shifting and I have a growl that starts about 50 and goes to 65 before it smoothes out. makes my mirrors vibrate! I hear what I think is bearing noise sometimes and I'm wondering just what I got for my 600. U joint is new, new pilot bushing, new engine. Growl does not appear to go away when I let off the gas so I don't think it is the rear end. I can live with it but it is loud and annoying around 50 to 60 mph. Anyone got an idea? This is my 46 1/2 ton and I drive it almost everyday.

Does the sound change if you push in the clutch at speed?
How about slipping it into neutral with clutch in and then out at speed?

I'll try that...

When at speed I pushed in the clutch, foot off the gas, and the growl went away. What does this mean?

Get the RPMs up while stationary. If you hear growl it's on the engine. If not, it's in the driveline.

I did rev it up with the clutch in and it was there. Fresh rebuild and supposed to be balanced. Would it be the flywheel? I can live with it but wanted it to be right!

You have eliminated the transmission and everything behind it.

An out of balance on the engine would be a vibration not a "growl".

You should be able to reproduce it by revving the engine with the truck parked.

I did have one with an odd "rumble" with engine revs. Was a bad motor mount that transmitted engine vibration into the frame.

A growl when you rev it up can be a sign of a bearing going. I would take the engine out and check the mains, to start.

It seems to be more of a vibration than a growl...my mirrors vibrate causing a blurred image but only at 50 to 60 mph.

If you slowly increase the engine RPMs with the truck parked, you should create the growl/vibration when you match the 50 mph engine speed. That would be around 3000, 3200 rpm. Watching and listening to the engine may give you a clue.

Possibilities:
Vibration damper, flywheel, pressure plate.
More obscure, iron pistons with a crank balanced for aluminum or mixed aluminum and iron pistons, one spark plug misfiring under load.

Thanks Jim, I'm hoping i don't have to pull the engine again...but I will if I have to.