I've got a strange clicking sound coming from my driveshaft at idle speed.

[haugy]

I noticed last weekend a clicking noise coming from my driveshaft only when in gear and at idle speed. If I ever so slightly give it gas it goes away. Noticed no vibration at speed or anything else.

Looks like my packing seal is starting to leak as well. (knowing the original owner it bet it's never been changed).


I don't think my drive shaft is out of round, but it may be ever so slightly and is wearing out the bushing in the strut or at the seal. What do you guys think?

[sybrmike]

How fast is the "clicking" sound? I wouldn't think the driveshaft would make a "clicking" noise. With that 1:1 tranny in gear at only idle, the shaft is turning ~800 rpm - that's still 13 clicks per second. Since mechanical noises are good at traveling through metal and often hard to locate the source, I'd try a stethoscope to see if you can better pinpoint. Clicking from the engine makes me think rocker arm, lifter, mech fuel pump, etc.

[haugy]

Nope, definitely not a rocker arm or pump. I know those sounds. And they would be there even when the engine isn't in gear.

This sound comes from the drive line itself somewhere from transmission down. The reason I suspect driveshaft or bushings as it picks up speed to a point at idle, and then clicks slower when the boat is put into nuetral and then finally stops. The clicking decelerates.

So I'm 100% it's not engine related. It's driveline.

[crystal waters]

had a similar problem on my 89 conbrio end of last summer.
Replaced the cutlass bearing and also discovered my shaft was in fact out of round so had it machined.
In doing all this also discovered the coupler was well worn and as a result my drive shaft was not seated too well so replaced the coupler and when machining the shaft had the keyway redefined.
This year - no clicking sound! As you can imagine- much smoother running when under power as well.
hope this helps.

[Okie Boarder]

Does it seem at all like it might be coming from the transmission? My transmission makes a little noise and is getting progressively worse. The first time I heard it the noise was pretty faint and it did have a bit of a clicking style to it.

[cadunkle]

Watching your shaft at idle in gear when it clicks does the shaft appear to wobble at all? Check alignment, but you might have worn strut bushings or a bent shaft. Tolerance is only a few thousandths, like .004" runout is max you want to be though it'll probably tolerate a little more. My shaft has about .002" runout and a performance drag boat guy said he'd have no problem running my shaft at 10k RPM in his drag boats. I guess there's a chance the click could be the shaft hitting your through hull tube, but if it was you'd clearly be able to see it wobbling as it would be really bad, probably would feel it pretty strong too. Also could be in the transmission, or possibly in the flywheel or coupler. Not sure if these boats have damper plates, rubber coupler, or a solid link. Maybe someone else knows?

[haugy]

Yeah, I'll probably check the driveshaft this winter for runout and accuracy. But it's weird because it just started doing at one point. I was cruising around the marina with no clicking.

Then all of a sudden it started, and hasn't stopped. So it would seem weird for the driveshaft to lose it's trueing like that. But maybe a strut bushing gave out. I'm not sure.

Okie: Almost 85% sure it's not coming from the transmission as I stuck my noggin down there while the wife was driving to check. My ears are my strongest sense and it was strongly coming from shaft/hull area.

[crystal waters]

I originally thought mine was coming from the transmission as well! Stuck my head down there a number of times as my wife drove the boat. Turned out as per my earlier reply it was the coupler, etc.
best of luck!

[haugy]

UPDATE:

Might have a hidden major problem. I went out last night, no clicking noise at first. Then as we were coming home and I was slowly planing off I felt a good bit of vibration and had a very faint dull noise(probably from the vibration). Then all of a sudden is just stopped and smoothed out. No vibration or dull noise. It ran fine all the way home. That to me means transmission issue.

Does anyone know if these thinks have damper plates, or have a schematic/diagram of these transmissions apart? If I have to rebuild or replace the tranny, it's definitely v-drive time.

[Okie Boarder]

They do have damper plates. Clint (csuggs) did a rebuild on his so he can speak more intelligently. From what I understand, DIM sells a rebuild kit for a reasonable price. I'm holding out on mine and probably will go that route when it decides to go. Mine almost sounds like a click and scrape mixed together and it comes and goes.

[lively]

Hey man i hope this helps , but the damper plate springs are real crappy ... as long as the velvet 1:1 is operating smoothly then damper plate is what you need ...

I took mine off when i pulled my pcm 351 and the springs were laying in the bell housing ... I have the manuals for the velvets 71 c 72 c if this is what you have send me your email and ill forward them to you ... and if you are going to print them ..... buy some paper lol they are 91 pages each ... great literature and exploited views

Oh and from talking to velvet re-builders - They are "holy" on maintaining fluid temp/level/ pressure .... the clutch plates will warp and break if this is not checked regularly

[Salty87]

good thinking on the damper plate. since this thread was first posted i've been stumped. i'll attest to the plates not lasting forever. i replaced mine too putting it all back together. from what i remember they aren't in a sealed spot and are very prone to rusting.

[riveredge]

I snapped my damper plate a couple summers ago - broke the weld on the splined ring in the middle, you could see that only about 10% of the weld was good, the rest was just poor welding. No warning at all, though, it just went. I was sure the transmission was cooked (~1000 hours at the time) but it's still fine at ~1340 hours. I check the oil every time I check engine oil, and I replace the oil every 100 hours.