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Overdrive clutch


Bill Wybenga

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I have a Warner Overdrive just installed, not used for years. All electrics work but when OD selected and engaged no power is transmitted to the drive shaft. Suspect that the Over-running clutch bearing is frozen.Works fine when OD not selected. Have put 10W-30 with 1/3 diesel gas in and ran it, drained and trying automatic transmission fluid now to free up the bearing. Any other suggestions short of removing the rear end and transmission?

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I had my redone some time ago, but yes you have to pull out the rear end in order to remove the transmission & overdrive.  You might as well go through both of them since it's such a pain to get it out.  There are parts out there from the listed sources on the club website.  You have to be careful with the transmission as there are different gears (different number of teeth) in the transmission should you need to replace it due to wear.  OD is pretty standard, there are places you can get a rebuilt OD solenoid which is very different than the old Ford units as it has a longer shaft.  Also good time when it's apart to change the clutch/throwout bearing and any other part that needs replacing. Clutch plate is also different from the Fords with a different spline setup.   I also had my flywheel removed and resurfaced/balanced so no clutch chatter.  Lots of old flywheels get warped and like a brake lining to the drum it doesn't make good contact.  Good luck with it!  

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The OD is pretty simple and usually reliable.  There is, however, a free-wheeling clutch so that if you take your foot off the gas under the governor speed of 22-24 MPH, the engine is disconnected from the rear wheels.  Probably worth checking the governor.  If the governor contacts don't close, you get the free=wheeling at all speeds.  I had a s governor that was full of gear oil (80-90 is recommended), and would not get an electrical connection.  You can ground the terminal that goes to the governor at the relay, should pick up the OD solenoid.  The circuit goes through the kickdown switch under the gas pedal, so if the kickdown switch is bad you could have the same problem.  Much easier than pulling the rear end.

Abe

 

 

 

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Thanks for the replies. I have previously gone through the electrics, everything works. When OD is selected there is no power transmitted through the transmission, to me that spells over-running clutch. Could there be other causes? I think I'll try Marvel Mystery oil in the OD unit next. Are there other magic potions to try?

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Are you sure the solenoid is working correctly and fully extending? The B-W overdrive in my '29 Cadillac would occasionally choke and leave me stranded in neutral. I'd have to pull over, stop the car, take it out of free-wheeling, and reset the whole system. It was the solenoid not fully energizing or only extending halfway. Endless headaches, two replacement solenoids, etc. Make sure the solenoid is actually firing beyond just having the system energize the relay that fires the solenoid.

 

Do you have this book? It's available from multiple sources and is a very worthwhile addition to your manual collection.

 

borg-warner-overdrive-service-manual-stu

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Thanks Matt. I do have that book. When the solenoid is initially energized it uses a high power (high amps) to drive the plunger forward then a contact opens (in the forward position) and a secondary solenoid (weaker) coil keeps it there. I can maybe watch the amps to see if that is happening. I think that I read somewhere that if it doesn't fully extend the high amps will blow a fuse. Other than the amps is there a way to check if the plunger is fully forward?

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  • 1 month later...

Freewheeling allows the rear wheels to turn faster than the engine and that is the same condition as when towing. If you wanted to tow to start the OD would have to be in manual (out) in order to turn over the engine when in gear. I assume you are just towing slowly for a relatively short distance (maybe home after a breakdown!) I wouldn't recommend it for long, at speed. 

 

Other opinions?

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  • 4 months later...

I am happy to report the source of my problem (OD not sending power to rear wheels) has been solved. The over-running clutch in the OD planetary drive has 2 tabs on it to prevent over rotation of the cage. These 2 tabs had broken off of my bearing cage. This allowed the rollers to rest in the cavity between the ramps on the bearing and so would not catch and lock up when driving forward. The light springs are not strong enough to 'lift' the rollers out of the cavity. The cage is heavy enough to allow new tabs to be welded to it, shape them to clear the bore and the bearing, over-running clutch can be used again.

 

101081266_Overrunningclutchcage1.jpg.e60f1d08df1b2e7617908a7df95bff8f.jpg

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