I have a 66 f100 with a 352 and 3 speed manual. When sitting still, clutch engaged or disengaged, will make this rattling noise from what sounds like the rear of the engine. It will also do this when the truck is slowing down (with clutch petal released) but won't hear it when depressing the clutch as rolling to a stop (when engine is idling). It will also do it during acceleration while moving. I dont have a tach but just from listening to rpm, it sounds like it occurs around 1500-2000 rpm and up. Any ideas on what this could be? I hope it's not like a rod knock or something extremely major like that. Thanks

 

If already have not done so suggest check the universal joints at both ends of the drive shaft for play. If bearings appear okay suggest tighten and using a grease gun lube. .

Another source possibly the throw-out bearing, First check for obstructions, cover plate etc. I purchase Federal-Mogul throw-out bearing which have a jerk fitting for lubing, suggest peeking under the clutch arm boot to check.

Anyhow, food for thought, since sound ceases when the the clutch is disengaged. Certain other member's will be chime-in with suggestions?

 

I thought that too or maybe pilot bearing, but it will do it whether clutch is engaged or disengaged. Doesn't matter. Won't do it idling. Only higher rpms. I know for sure it isn't u joints. It's up front in engine/tranny area.

 

 

On the tranny underneath, is that bolted plate where I can get access to the clutch and other parts? And I'm guessing no oil in it if that's right

 

 

Throw-out bearing