King Cobra (cone) chatter noise at idle in neutral

[EstorilM]

So if you're following from the other thread, they fixed the timing and the throttle travel issue (I was right and apparently it wasn't even close to WOT when the levers maxed out).

I mentioned to them that the motor sounded like the rotating parts / crank or bearings were making a marbles-type noise.. when they called me today they said that it was coming from the drive unit. Funny how they never mentioned the noise to me previously though. For the record it's a 92+ cone clutch king cobra drive - never noticed any noises or grinding or anything when it's in gear. Also it's probably one of the only KCs these guys have ever seen, and they might not be familiar with the larger FNR assembly in the upper unit or the larger u joints.

Does anyone else notice this kind of noise when in neutral / idle? How strong are the u joints and gimbal bearings on these? I know everything else is fairly BEAST but I'm not sure about those. How would I know if something like my drive bellow failed and that area was actually filled with water? Since it's ~23 years old at this point, how do they handle stupidity like starting the engine and forgetting to trim the unit down from trailer trim? I have no idea how many owners this thing has had or what's been done to it - I can only go on what I saw at the sales inspection.

Thanks!

[Morgan's Cloud]

If I'm not mistaken , that sound of marbles , or chatter is quite normal in a cone clutch outdrive.
Pretty sure I've seen it discussed elsewhere before.

My BIII did it once it loosened up from new and so did the DPSa .

[BUIZILLA]

ask Dr Dan..

[EstorilM]

Say wha?? Okay well thanks for the input so far! Mrfixx I will certainly check it before I go out this weekend - do you know what size the drain and fill plug are off hand? I'll search on the best fluids to run - obviously something with the best protection is preferable as I assume the shop put in the cheapest shelf brand possible. Silverish fluid would tend to suggest bearing failure correct? The fluid was changed when the engine was put in so figure probably 2 or 3 hours ago of actual running time, if that - not sure that's long enough to show anything or not.

On the flip side I can imagine the noise being louder than most of the smaller dog clutch units the shop is used to.. so who knows. My friend with an Alpha (2008 / new..) says that his also makes noise when in neutral.

[dsparis]

I've got a 91 KC, it makes no noise. Pull the drive and check gimbal bearing and u-joints.

[EstorilM]

I've got a 91 KC, it makes no noise. Pull the drive and check gimbal bearing and u-joints.

Well that's a bummer. Sounds like a 5 minute job too haha.

[Morgan's Cloud]

But you said it's only in neutral , right ? It's 'normal' when in gear ?

I'm tellin' ya , that's what both of my cone clutch units did once they had a few hours on them .
But dsparis' unit is quiet ?

[MOP]

I would check to make sure the cables throw is centered in neutral, the cone may have slight contact. Has the adjustment been checked???

[joseph m. hahnl]

Kc's from my understanding are very fickel to cable adjustment.