The Stovebolt Site Forums The Shop Area Driveline Noise in 64 C30 driveline

My 64 only has 29K original miles, but obviously it sat most of it's life unused. I just recently got it on the road, and there is an annoying noise coming from what sounds like the trans. It is in all 4 gears, and is on accel., and decel., but quiets down if you are just loping along without any load applied. Someone has told me it is probably the third member, and the noise is coming thru the driveshaft, making it sound like the trans. I dropped the oil from the trans and refilled with 80-90, and it made no difference. There was no appreciable metal in the oil when I did it. What is my next step in diagnosing this? Could it be the carrier bearing in the driveshaft??......or is it more likely the rear-end? I'm trying to eliminate all the simple stuff before I tear into the rear. Thanks in advance!

The differentials in those trucks are almost bullet proof, however it is not unusual for them to be noisy. It could also be the driveshaft center support bearing. It will cause a vibration that could emulate transmission and/or differential problems. Be sure to mark the sections before you take the driveshaft apart.
Fred

I was wondering if it could be that bearing. I am hoping I can find a quality replacement (not made in China) for it, and start there. The rubber membrane that surrounds it, is kind of dry-rotted anyway, so it wouldn't hurt to replace it.

Center bearings haven't changed much over the years. They come with the cushion. I think Carquest still has them.

You need to pull the cover off the rear end & see what you have. They are tough but driving with that old grease in it will soon destroy it. I think the noise is from the rear end.

The rear needs to be checked and refilled with new oil in any case. I would diagnose it by sound. If its a rumbling, its the center bearing. If its a whining sound, its the rear end. Both the rear end and the center bearing will quieten down when there is no load.

It's more of a whirring/whining sound than a rumble.....I need to get the cover off like you guys said, and see what I can find. When I did the rear brakes, I had to take the axles out (it's a dually), and when I did, the old oil looked pretty foul (as in black). I have wanted to change the oil anyway, so guess it's time. Now what if I can't visibly see anything wrong? Should I just button it back up and refill, and see if that quiets it down? Or should I tear it down.....??

There should be no side to side play in the carrier assembly. Grab the pinion flange. There should be no up & down play in the pinion brgs. Dont confuse gear backlash with brg play. There will be a small amount of backlash in the gears.

I would also feel the tmeperature of the center bearings after a good drive. It shouldn't produce any heat at all.

I currently have the rear cover off of the truck, and have drained the old oil. I am not able to feel any unusual movement in the bearings, and see no evidence of metal in the oil. I am waiting on a cover gasket, and will put her back together later this week with fresh oil, and see if that makes any difference. If that doesn't work, I also bought a new center support bearing, and will install that as well. We will get to the bottom of this sooner or later.

Well I finally got it back together. I put new 80/90 wt. gear oil in rear, and changed the support bearing (that was fun), and took it for a spin up the road........it is much quieter now! Trouble is, I'm not sure which fix did the trick, but bottom line is that it doesn't whine and whir like it did before! I love it when things work out!