driveline growl, what might it be?

[Firesong]

Another thing to note is that if you do go ahead and do the clutch release bearing , do the clutch
at the same time. Some of the release bearings are specific to the clutch. Ask me how I know.

IE don't buy them separate.

FS

[strada-caster]

Gearbox input shaft bearing will make noise all the time, but the noise will change when under load.

Pilot bearing noise will go away when the clutch is engaged (foot off the pedal) because the input shaft and flywheel are turning at the same speed- hence the pilot bearing isn't turning. Pilot bearings hardly ever wear out, since they don't take much load and only turn while you're changing gears. In the old days of bronze pilot bearings they would start to squeal during gear changes, which was always a bad sign.

Release bearings tend to rattle when the clutch is engaged (foot off the pedal) because they're held against the clutch spring fingers by a light pressure spring- so the release bearing is rotating at engine speed, but without much pressure to prevent them rattling. When you disengage the clutch (foot on the pedal) the release bearing is under much more pressure and so the rattle goes away- but if the bearing is close to failing it may produce a rumbling noise.

If you're replacing the release bearing it's usually a good idea to replace the entire clutch and the pilot bearing while you're in there, because if you don't you'll surely be tempting Murphy's Law.

In an earlier msg, I stated the following:
'' clutch engaged, driving, noise is there
clutch disengaged, driving, noise is not there
as soon as I press in the clutch pedal, the noise disappears. THat means the noise is comming from the clutch backwards.''
I should have mentioned this was when the truck rear end was still in the air.

I put everything back together whitout any repairs made.
Took it for a drive, first thing I notice is that the noise is there no matter what I do. clutch in/ clutch out, turn the truck off while driving and coast to a stop, the noise just slows down with the rpm right until stop.

Also, I can't hear anything at idle, even with my ear right next to the transmission.

So, looking at the quote above, this should eliminate the pilot bearing and the release bearing, and the input shaft bearing, leaving me with the last culprit "the driveshaft support bearing which was replaced 2 years ago""

[Growlerbearnz]

If the noise stays the same regardless of the clutch position, then I'd say you're on the right track, and at least the centre bearing is easier to replace than the clutch!

Let us know how you get on.

[strada-caster]

I finally took the driveshaft off and there is massive amounts of play on the steady bearing. hopefully when I put the new one on, that was the only problem.
:)

[Strada 92]

Good news!

[alovelyman]

I have a rear growling noise from the rear end of my van when I left off the throttle.

As I lift the throttle at highway speed the rear diff I get a howl noise. This noise is more prominent at highway speeds or when I have a full load in the van. If I play with the throttle I can make this noise on demand, not that I want to. I had someone look at the diff but they didn't find any problems. Could it be the drive shaft?

What the best way to diagnose this problem. I'm handy but a slightly intimidated to dismantle my rear diff. Any help would be greatly appreciated.