I've got a rapid ticking noise most noticeable upon deceleration around 1800rpm. I'm thinking lift pump because I've always had a tick at idle, just never got around to replacing the pump. Could be that it has finally decided to get bad enough where I will notice it more. New fuel lines 8 months ago, overflow valve was replaced about 6 months ago and the fuel filter about 7K back. Would a throwout bearing make a noise like this? Maybe I'll get lucky and cure it when I install my South Bend. Truck still runs fine. Last time I checked the valves everything was in spec.

 

My lift pump ticks always has, never been a problem though. Does it tick all the time? or just when decelerating? does it change with the clutch in ot out, or if you rev it in nuetral? I would think if it has anything to do with the clutch at all it would be the pilot bearing more than the throw out.

 

I've always had a tick at idle from the fuel system. I replaced the rubber lines and overflow valve. This sound seems new. It's not real loud; not like the fuel line pulse I can hear at idle, anyway. It seems more faint, maybe because of the other sounds of a truck in motion. Another thread metioned the throwout bearing making a ticking noise. It does change when I push in the clutch, but the rpms decrease so fast it's hard to tell if disengaging the clutch is really making a difference. It is definetly more audible when I'm not applying the go pedal.

 

Hmmm, hard to say. I know the pilot bearings are junk and fall apart long before the clutch wears out. I guess when you replace the clutch you'll find out for sure if its one of the two. If you want to upgrade your pilot bearing to a beefier one, go to your local bearing supply house or napa and ask for bearing #1635DC, then have your flywheel machined out to accept it. it will look like this when done

 

I keep putting the clutch install off. Looks like nows the time. Even if that isn't the problem, I'll have the pilot and throwout bearing eliminated from the mix, and a nice smooth clutch. I'll probably throw in a lift pump anyway, just because I'm tiring of the tick at idle. I'm a little nervous that it may be something in the valve train, but the truck runs fine and the've never been out of spec. Lots of stuff to rattle on this truck, so pinpointing noises is difficult. I'm stopping to pick up oil tonight, so I'll get a $10 stethescope and have another listen, even though the truck will just be sitting at idle, where everything sounds fine.

 

usually, the throwout will be noisy at idle foot off the clutch pedal in neutral.

I would do your LP before it dies.

 

Got to inspect a little closer last night. It definetly sounds like it is the lift pump. Another porblem, though, the vaccum pump rear housing is cracked. That bites. I just bought the new seals for it, and now the rear housing is junk.

 

Mine sounds the same. About 1800 rpm it is a quick ticking noise and then seems to go away as rpm decreases. I can't hear it any more below 1700 rpm until I'm sitting still at idle. It also seems to go away above 1800 rpm. Doe this sound like yours?
Andy

 

Yep, pretty close. I stethescoped the enigine at idle and I can hear it everywhere. It's most noticeable at the lift pump, so I'm hoping that is the source. I've replaced the OF valve and rubber fuel lines already. Still have a fuel line pulse, and the tick has gotten progressively worse. I hope it isn't something internal as I'm getting ready to throw some more $$ at this truck. I discovered a cracked vaccum pump housing when looking for the tick and I have a South Bend Clutch ready to go in next week. At 190K. Seems like a lot of people replace the lift pump about that mileage, so I hope that's the case with mine.

 

can't hurt.