Mystery sound from 4 speed top loader?

Have a '68 Ford Fairlane 390 wide ratio behind my 8BA using a MEC adapter and Merc. half bell housing. The car is up on jack stands with the floorboard trans. cover off and no gear shift lever installed or driveshaft. It has been converted to use the Jeep top shifter. In neutral at idle I hear a "rat tat tat" that I didn't hear when engine was on test stand without trans installed. Also, noticed the speedo. needle slightly bouncing around. Anybody have any ideas as to what is going on?

 

I hope you put oil in it! Without the driveshaft in oil should be running out,unless you have a plug or yoke in the output shaft.
The slipyoke supports the output shaft in a sleeve/bushing.

 

It does have oil with yoke installed.

 

Can you turn the output easily when in neutral?
Can you hear the noise then?
Can you hold the output and turn the engine over by hand or with the starter and listen for the noise?
The brass rings sometime click back and fourth in their register when turning by hand,but I wouldn't think you could hear that running.
Might be best to pull it out and re check,or,does the noise go away when you disconnect the speedo?
Does the noise go away with the top on?

 

Did you grease the cable? You can pull it out of the sheath and re-lube it. Also if the cable or sheath are worn, some frayed wires may be catching. They can also get sticky if the bends are too tight.

Could also be a bad gear tooth on the drive or driven cable gears.

 

What kind of pilot bushing did you use in the end of the crank?

 

Great ideas & will investigate all of them. The speedo. cable was lubed and am using roller bearing pilot bushing.

 

Check that speedo cable housing for damage, needle jumping and a rat a tat sound , sounds like the cable hanging up inside the housing.

 

Simple test would be to pull the speedo cable then run it.I have to agree with everyone on it being the speedo cable!! I have also heard of people having issues with the JEEP top shift,make sure ALL the gears are in neutral and not touching!! ROY.

 

Turned trans. yoke by hand and no noise. Put stethoscope on bell housing where inspection plate is and that seems to be the area where noise is coming from and not trans. case. But earlier had problem with shift lever and had to realign gate, maybe not all gears are in neutral position, although sound seems to be coming from flywheel/ clutch area. Will remove speedo. cable and inspection plate as well. I remember when installing the Merc. bell housing clearance for the pressure plate looked very close........maybe too close?

 

36tudordeluxe,
Odds are its the Jeep shifter, check it out like 65comet noted.

 

Okay, problem solved......... I think. Pushing the clutch in and releasing it made the noise go away. Any ideas on why that solved the problem........clutch to pressure plate issue?

 

You should have checked adaptor alinment before you put trans in..but may have just been some bind in the splines as the disc had not found its center yet and when you disengaged the clutch it let it.....

 

Hope that's the case!