I'm hearing a rattle sound from the area behind the instrument cluster, closer to the driver's door, left of the steering wheel. I'm certain its from inside the dash, not the engine compartment.

Does a '98 Ranger have a tach controlled by a physical cable turning or by an electric signal? I'm wondering if the bearings at the tach connection are wearing.

The noise goes away when coasting or at idle. Under load (accelarating or maintaining current speed) I get the rattle.

Has anyone else experienced this?

p.s. The noise is not the pinging sound commonly heard due to a bad MAF or lower octane under load.

1998 Ranger 3.0 automatic, 160,000 miles

 

Might be the speedometer cable? Does it sound like a cable rubbing inside a housing?

 

It sounds more like a chatter and sometimes a buzz when its quieter.

Here's what's happened recently last week: The bearing on the water pump seized without warning. It threw the belt and the water pump bearing and pulley fractured off the pump housing. Could this have caused damage to the valve train? My wife was driving it at the time, so I don't know how many RPMs the engined turned once the accessory load was removed due to the failed belt, but I thought this truck had an RPM limited anyways to prevent damage.

I hear no chatter at idle or when reving the engine to 3000 rpm in neutral.

Accelerating from a stop, I hear the chatter up to 48 mph when the gears shift and the RPMs drop to 1500 at which point everything is perfectly silent. I don't hear the chatter again until between 55 and 65 mph where the chatter is quiet loud, heard over the radio. At 70 mph, the chatter is nearly quiet and almost not noticeable.

I swear the noise is coming from behind the instrument cluster. But then again, sound has a mysterious way of hiding its real source.

Another reason I think it might be a tach or speedo cable, is that the truck has made this chatter/rattle since about 20,000 miles, typically when accelerating from a stop as the speed and tach increased, but it only did if for a few seconds and then would stop typically during the RPM drop to 1500 at 48 mph.

Any further ideas from anyone?

 

Your tach is electronically driven as is (I think) your spedo.

Could your noise be caused by something that is metal or metal shielded that goes through the firewall and is connected to the engine or transmission?

 

The water pump did give a warning, but it wasn't heard. Bearing don't just go bad, they go out slowly or faster depending on if they are overloaded from belt tension, but with the serpentine belt and tensioner set up that issue is all but eliminated. The bearing still makes a grinding noise when it's failing.

I am thinking it's a harmonic tremor depending on the speed. Have someone else drive the truck while you listen to various areas of the cab, it might be coming from another area.