Packard Forum Index » V-8 (1955-56)

I was riding in and driving a friend's 55 (with TU) yesterday and he was complaining there was a growl/grumble noise at various times. For example, it was very noticeable when I was going about 50 and up a bit of a hill, so I was on the gas a little. Hitting the gas even harder, OR laying off the gas, silenced the noise, but it was very audible in certain cases, though never loud.

He said it started after he had the Ultramatic rebuilt but to me it doesn't really sound like that type of noise, and it's most noticeable at higher speeds when the trans is in high/direct. So i think it may be coincidental. My vote is rear axle.

Thoughts?

The caribbean does that every now and then. I believe it is the transmission in my case. Typically I have to lay off the throttle then slowly get back on it to get it and keep that noise away.

It could be many things. I'd look for any evidence of an exhaust leak, and any evidence of any part of the exhaust system contacting the frame when the engine is under load, or any exhaust system hanger problems or modifications. Loose baffles in a muffler can cause strange effects. U-joint issues can cause noise or vibration or both. Wear, improper assembly, or lack of lubrication are some things to look at relating to U-joints, slip yokes, etc. Another area to check carefully is engine mounts and transmission mounts. I'd look at body mounts too, and check all engine accessory mountings and belts. Anything loose anywhere in the car, including the spare tire, jack, etc can make odd sounds under some operating conditions. In one unusual case, a small dent in the air cleaner housing caused a moaning sound at a certain speed. I'd check the rear axle lube, attachment hardware, shackle bushings and shock mounts.
Tires can make odd noises, so checking tire pressure and wear patterns is a good idea. Some pavement surfaces cause noise, so drive on a variety of surfaces and see if the sound changes.

Thanks TXgoat for the suggestions.

CarFreak where does your noise actually sound like it's coming from? What speeds / situations does it occur?

it predominately happens anywhere from 45-65. it doesnt happen at steady state cruise, but when I am accelerating or when its under load due to changing road conditions. it sounds like it is coming from the transmission tunnel

Interesting, thanks. This noise I think sounds like it's coming from the rear.

I wonder where your noise is coming from. Maybe it's just like that.

It's normal for the engine to shift on its mounts when under load which can cause normal mechanical sounds and vibration to be transferred into the frame and body under some operating conditions. I'd look real carefully at the exhaust system and engine/transmission mounts. Next would be the drive shaft, and then wheel bearings, underhood accessories, and rear spring shackles. Defective or modified exhaust systems can produce odd sounds.

In some cases, a clogged transmission screen can cause odd sounds, and low power steering fluid can make assorted noises in the system.

With two-piece driveshafts, u-joint phasing is important. If the driveshaft was removed recently and not replaced exactly as it was, it could cause vibration. That's true of a two piece or one piece drive shaft. Driveshaft vibration often occurs within a certain speed range, and it may be accompanied by a humming or low growling sound.

Service bulletin.

Hum. Raise rear end 3/8 thick plate front axle grommet .. under grommet.

Think it's like a thick U washer

Pinion angle?