Diagnosing new sound

[Ryperd]

There's a new sound coming from the engine, gearbox or drivetrain somewhere on Ryperd (4Y SFA), and I'm struggling to figure out where it's coming from. The sound is hard to describe, but I'd say it sounds similar to something brushing up against a fan blade (like a tick-tick-tick-tick-tick sound). It's not a squeal or a hum or a grinding sound (I'm trying to figure out what it is before it becomes a grinding sound). I seem to hear it only at low speeds and not all the time, even at low speeds. I've heard it in first, second and I think also third gear. If I hear it, pressing in the clutch seems to make it go away. The sound is definitely towards the front of the vehicle (in front of the driver's position). I've taken a look in the engine bay and underneath the vehicle, and I can't see anything that looks to badly wrong.

There's a bolt on the side with an electrical connection (what's this for?) which is leaking a bit of oil, but I tightened that up:


There's a bit of oil splatter around the clutch (I think it's the sump which doesn't seem to be perfectly sealed):


Also a bit of oil around the plugs, but I don't think that's too serious:


What worries me is that the sound started soon after I was towing a trailer with 2 pallets of bricks downhill (not too steep), using the engine for braking. There were no dramatic sounds or indications of something going wrong, but the strain could have caused something to go. If so, what would be likely points of failure?

My next plan is to change the oil in the gearbox, and look out for any bits of metal that drain out. Any other suggestions of what to check? I'd like to figure out what this is before I do any long-distance driving...

[pietpetoors]

Maybe loose springs in the clutch plate?

If it is in neutral and you rev the engine just slightly up and down can you also hear it?

[Rigger]

Sounds alot like tappets with too much clearance but you saying it disappears when depressing the clutch rules that out.

And the plug on the gearbox is the reverse light switch

[The Legend]

Sounds alot like tappets with too much clearance but you saying it disappears when depressing the clutch rules that out.

And the plug on the gearbox is the reverse light switch

Martiens the 4y tappets is not adjustable.It has hydraulic lifters.
"

[The Legend]

Rudi the oil on the engine I would say come from the spark plugs seals.When you remove the spark plug you will see there is an aliminium "bucket" with a rubberseal on the top of it in the head .Replace all four rubber seals.

[Rigger]

Sounds alot like tappets with too much clearance but you saying it disappears when depressing the clutch rules that out.

And the plug on the gearbox is the reverse light switch

Martiens the 4y tappets is not adjustable.It has hydraulic lifters.
"

Thanks for the note. Not that clued up with the older engines

[Mud Dog]

Rudi the oil on the engine I would say come from the spark plugs seals.When you remove the spark plug you will see there is an aliminium "bucket" with a rubberseal on the top of it in the head .Replace all four rubber seals.

+1

Also cut the spring washers off the plugs - they damage the bottom of the aluminium sleeve which then also starts leaking.

The oil between the block and bell housing is most likely a weeping rear crank seal - easy to replace next time you have the box out (like for clutch replacement). It's not serious yet (besides leaving oil marks on your driveway) but if it somehow gets onto the clutch plate (not likely at this stage) it will start slipping.

[LouisZ]

Oil Bucket seals for spark plugs +1

Time to check your seal on the Front Input shaft bearing, Toy part#90311-30014. These seals gets forgotten, last 2 I done was so brittle and caused a lot of gear oil to leak. These usually are mistaken that it will be the crank seal.

Check the crank seal if you strip down. Look what happened with this 1 I done last Sunday. You see the crank seal is dry and on the bell housing its totally wet.

[LouisZ]

Forgot to mention your sound will be the release bearing. All the dirty sand etc on it of the oil leak will make a sound.

[Ryperd]

Thanks for all the replies!

I had a long post written, but somehow it got lost so this one will be shorter.

Pieter, it only makes the sound when I'm moving. I took it for a short drive this morning to test again, and it actually does sometimes make the sound with the clutch in (and in neutral), just not as much. It's usually when there's a change in torque (releasing the accelerator or clutch) that the sound is loudest. It also sounds like an external sound now that I listen to it, so I'm thinking the UJ attached to the transfer case might be the problem.

Dawie, Andy, Louis, agreed about the plugs and buckets. It's time to replace the plugs anyway, so I'll just do everything in one go. It's not very clean at the moment, but it shouldn't cause problems.

I think if it's not the UJ, then it's probably the clutch. It's not slipping yet, but I've done 270,000 without any clutch issues, so it's probably due. That might be the next lesson in my mechanical training, otherwise I might see if Louis has a gap to make this the 3rd input shaft bearing he's done lately!

[Ryperd]

I sprayed some Q20 into the UJ and the sound seemed to get better, so I think I'll replace that and see where we go from there.

[Mud Dog]

Pump some grease into those universal joints and slip joints on both shafts, there should be grease nipples on them. The front shaft has a double cardan joint at the x-fer box, so there are two nipples there. The front shaft should also not be turning unless you are moving with the hub locks engaged or are moving and have the X-fer box engaged.

[Ryperd]

I replaced the two front u-joints on the rear shaft (the back one I replaced recently). Also checked the centre bearing while I had the prop shaft off. It seemed to be in good nick, which is nice. The sound is definitely gone, so I don't have to do the clutch just yet ! I think the moral of the story is that if there's a strange sound from the drive-train, it's almost certainly one of the universal joints (unless it isn't)...

I tried pumping some grease into the universals, but the nozzle I have is too fat to fit onto the nipple properly - the grease just goes around the nipple no matter how I push it on. Is there a special grease gun attachment for universals, or is this just operator error? I went to a few spares and tools places, but it seems that I already have the standard fitting, and they didn't know about any smaller nozzle.

[Mud Dog]

Your grease gun nozzle is probably the correct size. It could be that the old grease has solidified with age and dirt inside the nipple - remove the nipples (they just turn out) and soak in petrol for a few minutes and then blow out with compressed air before putting them back.

[Rigger]

What i always do is grease the universals before i put the shaft back because then you can turn the yoke so that the clearing is big enough for the grease gun to fit in. But this advice means nothing to you now