Overdrive trouble

[MilesP]

I am stumped my 51 will not shift up to overdrive just quit last month. Took to mechanic he did all the tests from the shop manual relay ok ,floor switch ok, removed rail switch ok, governor came on at 30 mph. Solenoid  removed and tested ok, no power to one side of the rail switch, jumped the rail switch
Terminals still wont shift what could it be? Any ideas

[Fid]

Hi Miles, a weak charging system or weak battery may cause it. The solenoid takes almost 20 amps to pull it in so any extraneous load on the electrical system can cause the overdrive not to work. If you have another battery handy, and it's fully charged, it's easy to swap it and see. Also a corroded fuse socket can cause it too. Try removing the fuse and scrape the socket clean with a pocket knife - also the ends of the fuse itself. That's easy and I've seen it cause problems too.

[MilesP]

Lowell battery strong three new fuses the person I took it to told me "Checked out overdrive tracked down to a bad actuator in the tail shaft of transmission for cable driven overdrive switch " How does the cable attach to the tray . I noticed when operating the cable little or no resistance when sliding it in or out could this be broken or is their something broken Inside?

[Fid]

The "cable driven switch" is likely the rail switch which opens when the car is in reverse. It should be close when it's in any other gear. The rail return spring could be broken inside the OD and lodging against the switch keeping it open.
That's hard to tell as that lever does move with little or no resistance even under normal conditions.
When the OD cable is pushed in does the car freewheel? If so, the mechanics are working OK which means you can try jumpering the rail switch out of the circuit. The only thing the rail switch does is prevent the overdrive from engaging while the car is reverse. Since you can't get up to 29 mph in reverse, jumpering it out should not cause any problems. What I've done is disconnect one wire from the rail switch and then put it back on the other terminal so both wires on the rail switch are connected to the same terminal - this jumpers it out of the ciruit. If the overdrive works after doing that, then you either have a bad rail switch or perhaps the spring is broken and lodged against the button on the switch enough to open it. Jumpering it out of the circuit will be the telltale.   

[MilesP]

Lowell the car does not free wheel jumped the rail switch out of the circuit but no luck . Still not confident in the OD cable so I ordered a new one from Erma Walker . Hope it is not an internal problem the local tray shops don't want to work on old cars.

[Fid]

Best of luck Miles. If it does not freewheel that's not a good sign. That means the mechanism inside has not moved into the correct position. Jeez Miles, I wish I was a little closer. I'd be happy to look at it with you. Your nice maroon '51 Special needs to be on road. If it is that spring insided the OD, the cover will have to come off. I don't know what it's like on a Kaiser but it's not too bad on the J. About a 2 hr job.

[MilesP]

Lowell thanks for your interest my 51 will be on the road just not in overdrive. I will canvas the local tray shops to see if I can get help

[Fid]

Miles, you may be onto something with the cable - I was out working on my J tonight, put a new OD cable grommet in it. I noticed when I disconnected the cable, the lever on the trans falls into the "non-OD" position on its own so if your cable is connected wrong or is the wrong type, it may not push that lever back far enough to get the gears to engage. If you push the cable all the way in, then disconnect it down at the trans, then pull the lever it connects to (the one on the side of the trans) all the way back, as far as it will go, the connect the control cable that may do it. It seems I had this happen to me once - I connected the control cable when that lever wasn't all way back - be careful though as if you get it halfway between it could cause problems.

[MilesP]

Lowell  overdrive works perfect after spending almost $200 it was a small adjustment  1/4 inch on the cable to get it to activate now all is good . Will leave the rail switch jumped unless you think I should put it back on line .

[Fid]

That's good news Miles.  Regarding the rail switch, mine's been jumpered out of the circuit since the 1970s. The purpose is to prevent the circuit from energizing while the car is in reverse. You can't get to 29 mph in reverse (the speed required to close the governor switch) so it really doesn't matter. Next time you're under the car for some other reason you connect it back if it bothers you but there's no urgency. I'm glad you were able to get it fixed.

[darrin145]

Am I correct in assuming if you jump the rail switch, leave the overdrive "on", put the car in reverse (as I usually do) to park it, without setting the parking brake, the car will roll out of the driveway and crash into the neighbor's mailbox?

Gary.

[Fid]

Short answer is, the car will not roll away in reverse if that switch is jumpered out.
The freewheeling is controlled mechanically; the electrical circuit has nothing to do with that. Any time the cable is pushed in, the vehicle will freewheel when it's in the foward gears. That's why the car needs to be parked in reverse or it will roll just as you say. When you put it in reverse, there is a cam on the inside lever in the trans that pushes the control rail back which engages the sun gear with the planetary gears as they are when you're not in OD.
I don't trust my parking brake that much so I always park mine in reverse!  The rail switch just prevents the electrical circuit from possibly energizing while the car is in reverse - that's all it does. The governor switch closes when the car reaches 29 mph so as long as you're below 29 mph (which is always the case in reverse) it does not really provide any benefit. Also when you shift into reverse, as I mentioned, the lever pushes the sun gear back so mechanically the OD cannot engage either so it's protected both mechanically and electrically in reverse.

[kaiserfrazerlibrary]

The main function of the overdrive rail switch was to prevent the transmission from kicking into overdrive when going in reverse.  Tests by engineers at Willys Motors (this was done after 1953) showed that given the vehicle gearing (including passenger cars) the 4.55:1 and 5.39:1 axles used in production did not let the car go fast enough in reverse for this to happen.  A change order, backed by a service bulletin were written to delete the switch on production.  I don't have everything unpacket yet (I thought I did but 1 box still appears to be missing) so I don't have the Service Bulletin number handy.

[MilesP]

Found a note in KW bulletin 290 March 14 1955 that the overdrive switch would be eliminated in future production in all Willis passenger care

[Fid]

Thanks Miles. To me that switch was always just one more thing that could fail!  This is good to know.