Packard Forum Index » Post-War (1946-54)

Howard and Owen,
I disconnected the fuse to the firewall mounted relay that controls the overdrive solenoid and test drove the car to make sure the overdrive was in fact disabled. The kickdown switch appeared to operate normally as indicated by a click at the 22mph point and the overdrive did, in fact, not engage when I tried to 'kick' in so I know it was disabled. While stopped, engine idling in neutral with clutch depressed, clicking sound from ender the car continues. My next step is to clean up the wiring and connections at the solenoid and lockout switch on the overdrive unit itself. I will take a look at the lockout switch and see what I can find. Have you known these lockout switches to go bad? Any other suggestions?
Thanks Again!

The relay on the dash will continue to work when the fuse is removed, it merely doesn't have any electricity to send down to the solenoid, so the overdrive will not engage. You will hear the click at 21 mph as you noted unless the lockout knob is pulled out, in which case you should not hear it.

Be that as it may, there is nothing electrical to go click click down there when the clutch is depressed especially when the fuse is out. My best guess is that your throwout bearing is failing in an odd manner, or the throwout bearing return spring has broken and flicking against something inside the bell housing.

Any switch can go bad but since you hear the click at 22mph it doesn't sound like your lockout switch has a problem. The failure that has been reported more than once on the pre 51's is the plastic plunger end wears. When that happens the switch internals can't move enough and complete the circuit when the knob is all the way in. No OD at all when that happens. The 51-54 switch is located on the OD unit and operated by the lockout rail. Don't recall anyone mentioning a problem with those. 55-56 had no lockout switch.

I can't think of anything electrical under a stock car that would make a rhythmic clicking noise. Unless someone has done some strange wiring, pulling the OD fuse prevents the solenoid from making it's clunk sound. As Ross mentions, even with the fuse out the firewall relay will still click when a ground is provided. The only clutch related way that I can think of is if the clutch linkage might somehow be touching against the wire going to the lockout switch and governor and making it short against something. If so, vibration could possibly cause it to make and break to energize the relay. Would expect the click noise to be very erratic if that were the case.

Gentlemen, thanks so much for helping me trouble shoot this issue! I will get under the car tomorrow and take a closer look at all the wiring/linkages and get my stethescope out like Dr. Kildare and try to pinpoint the exact source of the noise. I will get back to you.