Drive Train Noise

[Joe/Ct]

I'm stumped. Our '28 roadster has developed a noise when we are driving.
It does not occur in first or second gear (at least we can't hear it over the engine noise), but only third gear. It's like a continuous rumbling noise, that only appears when under load; when I take my foot off the accelerator or push in the clutch, it goes away. The oil level of both the transmission and differential have been check and both are full. Any ideas?

Also, is there a problem to continue to drive it this way?

 

[ericr]

could it be the clutch throw-out bearing?

 

[SeaSlugs]

does it do it in neutral when revving the engine?

does it appear to be front middle or back of the car?

muffler hanger seem to be tight?

engine mounts seem tight?

does it sound like a deep deep noise like a tuba or kinda "thin metal" rumble?

what speed are you entering 3rd gear?

does it get deeper/louder when you try to accelerate hard in 3rd gear?

 

[Joe/Ct]

Excuse my caps response below.....not trying to shout, but to highlight response...

does it do it in neutral when revving the engine?
NO

does it appear to be front middle or back of the car?
MIDDLE

muffler hanger seem to be tight?
YES

engine mounts seem tight?
YES

does it sound like a deep deep noise like a tuba or kinda "thin metal" rumble?
YES

what speed are you entering 3rd gear?
10-15MPH

does it get deeper/louder when you try to accelerate hard in 3rd gear?
YES

 

[Joe/Ct]

could it be the clutch throw-out bearing?

My understanding is that the throw-out bearing is disengaged when the clutch is out....

 

[Jim/GA]

Sounds like it could be U-joint and/or front drive shaft bearing.

Hard to diagnose car noises without actually hearing them in person.

 

[BILL WILLIAMSON]

Chuck fixed a NOISY car that had been stored a LOOONG time, by removing one of the speedo drive mounting bolts & SQUIRTIN' in a bunch of 600W oil.
"Maybe" the drive shaft bearing was DRY??? or "maybe" some of it made it's way to the U-Joint??? He said it was a HORRIBLE noise, they were about ready to pull the rear end, but the noise went away IMMEDIATELY & PERMANENTLY.
Bill W.

 

[vermontboy]

If you are shifting into high gear at 10 mph you are shifting too early for a 4 banger and you are lugging the engine and putting stress on the driveline components. Try waiting til you're up closer to 20 mph before shifting into high gear.

 

[Jerry Kzoo]

Your best bet is to put the rear end up on jack stands and have someone use a mechanics stethoscope to try to find where the noise is coming from.

Not to scare you, but we are working on a club members car right now that had a broken tooth on the rear end pinion that caused a noise in third gear.

See this post for an explanation:

http://fordbarn.com/forum/showthread.php?t=80039&highlight=3rd+gear+noise

http://fordbarn.com/forum/showthread.php?t=73010&highlight=3rd+gear+noise

http://fordbarn.com/forum/showthread.php?t=73384&highlight=3rd+gear+noise&page=2

Good luck on solving your problem!

Jerry

 

[Mitch//pa]

you can see the diff ring gear teeth through the plug hole

 

[ericr]

My understanding is that the throw-out bearing is disengaged when the clutch is out....

I'm sorry, I meant to say pilot bearing in the flywheel. but upon reflection, was your transmission rebuilt with new bearings?

 

[Mitch//pa]

I'm sorry, I meant to say pilot bearing in the flywheel. but upon reflection, was your transmission rebuilt with new bearings?

the crankshaft, pilot bearing and main/input shaft are locked and rotating together when the clutch pedal is not depressed..

 

[SeaSlugs]

If you are shifting into high gear at 10 mph you are shifting too early for a 4 banger and you are lugging the engine and putting stress on the driveline components. Try waiting til you're up closer to 20 mph before shifting into high gear.

my thoughts too, a lugging engine will create a deep rumble from what seems like everywhere.

id try what vermontboy said and take it for a quick spin but not shift to 3rd untill 20mph. Its free to try and eliminates something

 

[Joe/Ct]

Just an update. We haven't taken the ****** apart yet, but I took a local mechanic for a ride today and he diagnosed bearing noise. I have already ordered the full compliment of bearings and will remove and open the ****** when they arrive. Will keep you posted.

By the way, I mis-spoke when I said that I was shifting into third between 10 and 15 mph. It is actually 20 to 25.

 

[Purdy Swoft]

p

Chuck fixed a NOISY car that had been stored a LOOONG time, by removing one of the speedo drive mounting bolts & SQUIRTIN' in a bunch of 600W oil.
"Maybe" the drive shaft bearing was DRY??? or "maybe" some of it made it's way to the U-Joint??? He said it was a HORRIBLE noise, they were about ready to pull the rear end, but the noise went away IMMEDIATELY & PERMANENTLY.
Bill W.

Thanks bro, I see now that I spelled PERMANENTLY wrong on another thread. Purdy S. smiley face.