1951 Ford overdrive
 

I have a question re: the Borg Warner OD. I recently read this (paraphrased) post on another forum:

If your OD is not working electrically just mechanically, with the cable pushed in to activate the OD, the transmission will be freewheeling when you take your foot off of the accelerator. The engine will return to idle even if you are still moving at a normal highway speed . When you again depress the accelerator, the engine RPM's will "catch up" and again power the car. In other words, the OD may not actually go into OD with the planetary gears powering another gear, but simply allowing the transmission to freewheel.

Again, I am paraphrasing the original post, but if this is accurate, how would you test the system, assuming that all the correct electrical and mechanical connections have been made? In this case, all the components are new or NOS and the transmission was professionally rebuilt.

When driving, this seems to be the situation that I am experiencing. When the accelerator is firmly depressed there is no apparent return to the lower gear. On the other hand when cruising at 40-45 MPH with the accelerator depressed,the engine sounds like it is operating at a lower RPM than when the cable is not the OD ("on") operative position. I have never driven a car with this system and recognize my ignorance on this subject. Any advice would be appreciated. Thanks in advance.

Re: 1951 Ford overdrive
 

It's an electrically operated system so it needs to have functional switches, relay, and solenoid for it all to work properly. When the cable is pulled out, the lockout rail effectively moves the sun gear out of mesh an blocks the operating solenoid pawl that does the shifting of the OD planetary. In other words it works pretty much like any manual 3-speed when locked out. When you shift the car into reverse whether the cable is pulled or not, there is a mechanical mechanism in the reverse shift that pushes the lock out rail so that is will always be locked out in reverse.

The firewall mounted relay is the control relay that turns the operating solenoid on & off. The free wheeling clutch has to be there for the overdrive to shift so it has to be fully functional when the unit is locked in with the cable pushed all the way in. The governor on the tail housing has a simple switch to turn the system on when it reaches on speed around 23 MPH.

Ford recommended using the OD as a semi automatic transmission when driving around town. You just leave the car in second gear and only use the clutch when you stop. Starting in second is possible when the car is not loaded too heavily. This way a person can drive away from the stop and let up on the throttle above 23 MPH and it will shift into overdrive. It's basically operating as a 2-speed transmission with a clutch. Whether this works or not depends on the speed limits where the car is operated and is not necessarily the best way to operate it if conditions don't match up well with those speeds.

There are a lot of tests that can be done on the system if something isn't functioning as it should. I would recommend getting the shop manual for the type car you have. there should be a full section of the overdrive system that includes the test procedures. Jumper leads and a test light is all that is required to perform most tests.

The operating solenoid only has two terminals on it but they both perform different functions. Grounding is provided by the drive train to battery ground connection. One terminal is an ignition coil kill circuit for the downshift function and the other is to function the operating solenoid to shift the transmission into and out of overdrive.

There are other threads on here that have wiring diagrams or you can find them on line. If the system is going into overdrive then the kick down switch under the throttle pedal has to be depressed all the way to get it to downshift out of OD. It will also drop out of overdrive when the speed of the vehicle drops below the ON Speed of the governor. It should be out of overdrive any time you come to a complete stop. When it shifts in, you will notice the drop in rpm. If you don't feel it going into overdrive planetary gear then it isn't working correctly. The kick down switch, governor switch, and relay all have to be working. Some of the older units also have a rail switch in line with the governor switch control that can give problems. Later models eliminated that switch as redundant. It can be bypassed if it's not working properly.

Re: 1951 Ford overdrive
 

Simply put, if the transmission is "freewheeling" above 30 mph with the handle pushed in, it is not in overdrive.

Re: 1951 Ford overdrive
 

The way I always check is to accelerate up to ~40 mph or so, and by this time will be in 3rd. Let up on the gas pedal, you should feel the car go into a higher gear (lower RPM, less acceleration response when you hit the gas) as long as the OD is not locked out. Then, if you kickdown by stomping on the pedal, you should feel the opposite when the car goes back to normal 3rd (lower gear: increased revs, increased acceleration response)

Re: 1951 Ford overdrive
 

First I want to clarify the purpose of that handle labeled "overdrive". It does NOT "turn on" the overdrive when pushed in! It just allows the overdrive to operate as designed when pushed in (its normal position). All overdrive functions are electrically operated only. This cable is properly called the "lockout cable". Its main function is to provide more engine braking on a downhill grade. It essentially turns an overdrive trans into a standard three speed trans when pulled out, as mentioned in an earlier post. Any early '50's to mid '60's MOTORS or Chilton's etc. manual will have a wiring diagram and troubleshooting instructions.

Re: 1951 Ford overdrive
 

The 3 on the tree manual with OD will free wheel by design. Put your e brake on when parked on a hill. Always ran mine on the 53 around town with the od off/out. Great transmission. Everything well, it cruises 70mph all day long with low rpms to the engine on the hwy, engaged.

RotorWrench post is very informative.


.

Re: 1951 Ford overdrive
 

When you get past 30, let up on the accelerator and listen for a thunk, what it sounds like to me, that will be the OD shifting in. Sometimes it is easier for me to hear it in second. Someone wrote earlier about driving around in 2nd OD. While that is possible it is not recommended. OD cars came with a 4.11 ratio so being a little lower you could start off in 2nd and shift to third without the clutch, and then let up on the gas to shift to OD. Depress the gas to shift out of overdrive, let up to shift in again.
If it is just not shifting out then your switch may not be addjusted properly or the grounding circuit is not working. The points need to be shorted to remove power from the input shaft to let the solenoid drop out.

Re: 1951 Ford overdrive
 

Thanks so much for all of your input. I suspect that there is an electrical or a component issue. I have the wiring diagram and the wiring harness is color coded the same as those described in the factory manual. Would anyone have a specific online reference for a proper trouble shooting procedure? Unfortunately my reference library is rather limited. Thanks again.

Re: 1951 Ford overdrive
 

I answered my own question. This is a fantastic article with a complete troubleshooting guide.

https://fifthaveinternetgarage.blogs...verdrives.html

Re: 1951 Ford overdrive
 

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Re: 1951 Ford overdrive
 

After doing some of the testing outlined in the above mentioned article, it appears that the solenoid is not functioning. When battery voltage is applied to the #4 terminal and the a ground is applied to the case, the expected (hoped for ) "clunk " does not occur. My question is,until I have a working solenoid, is there any concern about driving with the OD cable pushed in and the transmission continuing to freewheel? The car is actually more pleasant to drive when the engine's RPM's are allowed to drop when not accelerating. The gearing with the OD rear end is such that the RPM at 45-50 make the engine sound like it needs that other gear included in the Borg Warner OD. On the other hand, I don't want to do any harm to the transmission by keeping the mechanical part of the OD setup in use if it is not advisable. Thank you for any advice that may be offered.

Re: 1951 Ford overdrive
 

If the solenoid is non functional, a person still needs to make sure the firewall relay and the switches are working too even if the operating solenoid it bad. It's easy to remove the solenoid and do further inspection and testing on the bench. Most of the electrics were placed in a swampy area so they deteriorate faster due to that. Sometimes they just need a bit of TLC to restore function but a person won't know until they tinker with them a bit.

Re: 1951 Ford overdrive
 

It won't hurt the transmission to drive with the handle pushed in. Keep both sections of the transmission filled with oil and park with the transmission in reverse, as it will roll forward in any other gear.

Re: 1951 Ford overdrive
 

Mr Laser

A caution in testing the selonid. On the bench use the voltage from the vehicle battery or a heavy duty charger. 6 volt lantern batteries or 3/4 amp chargers don’t provide sufficient current to operate the selonid, causing false test results.

The selonid is usually not the cause of OD trouble.

Hope this helps,

Tom

Re: 1951 Ford overdrive
 

You won't hurt the trans but your brakes will take a beating because you won't have any engine braking. Do a back-to-back test; first with lockout cable pulled out, then with it pushed in and see the difference.
Have you checked the glass fuse on the relay? They can look good through the glass but can be broken at the end behind the metal cap. Use an ohm meter or test light to check.
Check the solenoid with an ohm meter also. An open circuit will show infinity. Remember to check between the heavier wire and the case.

Re: 1951 Ford overdrive
 

Thanks for all the suggestions.

I did check the fuse ( separately) and also found battery voltage before and after the fuse on the relay with the ignition in the "on" position. If I remove the solenoid for bench testing and it is not working, will I be able to reinstall it until I get a replacement? I watched a YouTube video showing the instillation of the solenoid which indicated that the plunger needed to be extended (using battery activation) when installing it. I would like to be able to continue driving a bit while waiting for a replacement. The speed limits here in my neighborhood vary from 25 mph to 45 mph and the braking system is new. I'm hoping that bit of driving won't be too hard on the brakes. Thank you all again.

Re: 1951 Ford overdrive
 

I have the original R10 BW overdrive which was installed at the time of the factory build. As noted in the above posts, I have been unable to engage the overdrive in spite of now adding a new solenoid, new relay, new wiring harness , and new kick down switch. The governor is nos and was installed during a professional transmission rebuild. With the OD cable pushed in, the transmission freewheels normally. When 30 mph is reached and the gas pedal is momentarily released, no shift into OD takes place. In Randy Rundle's Overdrive Manual, the governor is tested by removing its cover, separating the points ,and grounding the cover. Unfortunately, on my car there is insufficient floor pan clearance to be able to remove the cover screws to accomplish this test. BTW, with the key on, both the relay and the solenoid click simultaneously when the TH terminal on the relay is grounded. I have ordered a proper sized wrench to remove the governor should that be necessary. I would appreciate any other suggestions for an alternative means of testing the governor without the necessity of removing it. Also, does anyone know what type of nylon (??) gear is attaches to the governor"s shaft? Thanks in advance for any suggestions.

Re: 1951 Ford overdrive
 

The governor is the last permissive in the circuit. The kickdoen switch is the first and only on a 51. If you unplug the wire from the governor and ground it with the key on you should hear the relay and the solenoid click. If you do not then I would investigate the kickdown switch. Make sure you have the kickdown switch wired correctly. The upper most terminal should connect the governor to the relay.

Re: 1951 Ford overdrive
 

Grounding the wire will check the wire but not the points in the governor switch. Unscrew the governor and pull it out so you can check the points on the bench. If they open and close and have continuity when closed then the governor switch is OK. The flyweights should be secure and move easily. The gear should be metal. The governor shaft is held in the gear by a spring ring. Gear lash may be visible from the speedo gear side. If it has the wrong gear then there would be a problem. These governors were used on a lot of different cars and some had different gears depending on the transmission they were set up for.

Re: 1951 Ford overdrive
 

Thanks for the replies. I do now have a properly sized wrench and will remove the governor for testing. I also will recheck the kick down switch for proper wire placement.

Re: 1951 Ford overdrive
 

If the wiring is ok up to 3 inches of the switch I think we can determine it is the switch. I was tring to give hime some alternatives to virtually removing the transmission. To remove the governor you nedd to unbolt the cross member and all associated linkage as well the speedo cable. You may need to lower engine to get at the 4 bolts that hold ot to the bellhousing. You can the rotate the transmission so you can get at the governor.
Also i saw you ordered a special wrench, I've removed mine with a pipe wrench or even water pump pliers. You can spin the governor with a drill motor while held in a vise and watch the action of the centrifugal part of the switch. I had to clean up the poins on mine once. Even harder on a convertible with the X frame.

Re: 1951 Ford overdrive
 

An old Ford adjustable wrench will generally work to loosen the governor. I know its a tight fit in there on Ford cars since there is no removable floor panel like the Mercs have but I would think that it still could be removed without all that trouble unless it's a convertible X-frame. The governor is aimed at an upward angle which should help with the cross member but I don't know about the floor. Ford car tunnels are a bit small. It might be easier to clean it off and try to get the screws out that hold the cap.

If it's that much trouble then a test light would make more sense. Attach a jumper lead to a convenient power terminal or the hot side of the battery and connect the test lamp to that jumper with the other side jumpered to the governor switch wire or terminal. Run the car up to on speed and the light should come on. It will go out at a slightly lesser speed when decelerating. That would confirm governor switch function anyway. Repairs might be another matter if required.

Re: 1951 Ford overdrive
 

Thanks again. The car is a Victoria with a conventional, reinforced frame under the doors. This was a factory modification.

Re: 1951 Ford overdrive
 

Well I have had a bit of luck on the floor pan issue. I was able to remove the governor with a 1 1/2" Martin open end wrench without any other changes. I assume that the floor pan "hump" was enlarged in 1951 because of the introduction of the Ford-O-Matic transmission. This provided the necessary clearance to be able to remove the governor. I will bench test the governor and provide more feedback. I thought that the floor pan information might be useful to someone in the future. Thanks for all your help.

Re: 1951 Ford overdrive
 

I added an overdrive transmission to my 51 Deluxe, which originally had the standard three speed. I ran it for a long time with a toggle switch that simply provide 6V to the solenoid. Run the car up to speed in third gear, flip the switch, release the accelerator and you are in overdrive. Now I have the full control circuit which works well, though I find it slightly painful flooring the accelerator to disengage the OD at speed greater than the governor cutout. Good luck, the extra gear is fantastic

Re: 1951 Ford overdrive
 

It makes sense about the floor pan. 1951 was the first year for the Ford-O-Matic but I think a lot more Mercury cars were sold with Merc-O-Matics than Ford cars with Ford-Os for that year. The Fords with 6-cylinders didn't get the Ford-O-Matic till 1952 when the 215 came out. Only the V8 was set up for it in 51. The bell housing with the air cooled torque converter is a big damn thing. It would have needed more room for that.

Re: 1951 Ford overdrive
 

As a f/u to my previous posts and my current status I am posting this summary:

I am asking for advice on the continuing problem I am having with my Borg Warner r10 OD. The transmission was professionally rebuilt several years ago ( but not put in service at that time) . The rest of the car's frame off restoration has now been completed. When driven, the transmission functions normally when the OD cable is pulled out. When the cable is pushed in, the transmission free wheels as expected. When approximately 30 mph is reached and the accelerator lifted, the OD does not engage and freewheeling continues. The wiring harness is new and the solenoid,governor, and relay were all NOS at the time of the rebuild. I have since replaced the relay and solenoid with new ones from Vintage Auto Garage. I also replaced the original governor with another NOS part. I have Randy Rundle's book and have tried testing the system as he described. In spite of these changes, I still cannot get the OD to engage. As a test, I have installed a toggle switch wired directly from the battery to the switch and then to the #4 terminal on the solenoid to bypass the other electrical components and wiring. When tested in the garage there is a click at the solenoid. When the switch is turned to the "on" position at 30 mph while driving and the accelerator pedal is monetarily lifted, the result is the same, with continued freewheeling. A few other details: the car is 6 volt positive ground and otherwise stock. Unfortunately the original transmission (elderly) re builder has since passed away. Also, when installing the second solenoid , I did turn the unit clockwise, while powered "on" to extend the shaft, then rotated it counterclockwise when it was in place to align the bolt holes. When the power was cut to the solenoid, it was drawn flush with the case. I should also mention that the transmission was originally briefly filled with synthetic GL-4 fluid and subsequently changed to GL-1 mineral oil based lubricant. I am now wondering what other testing might be helpful and have concerns that the problem could be an internal mechanical one. The transmission otherwise functions nominally. Very frustrating. Any help would be greatly appreciated.

Re: 1951 Ford overdrive
 

Sorry to hear that it's still not working. Assuming #4 is the correct terminal on the overdrive solenoid, using a toggle switch to that should directly energize at and engage the overdrive when you lift off the accelerator. You've bypassed all the additional complexity which is good. When you push the overdrive lockout cable in does the arm on the overdrive shifts all the way back toward the tail shaft (is it properly adjusted to allow full movement of the OD lockout arm?). It seems like it might be something internal unfortunately... Ken

Re: 1951 Ford overdrive
 

Ken,

Actually , I have removed the floor cover and can see the arm. It is is fully switched to the rear and I can hear a slight "click" when it is put in that position. Thank you for the suggestion.

Re: 1951 Ford overdrive
 

You might give Mac Vanpelt in OH a call. He rebuilds these transmissions and may have some mechanical checks you can do with the unit still in the car. Ken


http://www.vanpeltsales.com/FH_web/f..._contactpg.htm

Re: 1951 Ford overdrive
 

While rereading the overdrive booklet I wondered whether the situation described in the attachments might be the problem and the solution. I'll give it a try and provide f/u.

Re: 1951 Ford overdrive
 

Thanks for your suggestion Ken. Before moving from Ohio to Savannah I lived near Mac Van pelt's operation. If I don't resolve the problem with the above steps I will give him a call.

Re: 1951 Ford overdrive
 

Interesting, I hope that fix works for you. If not, I can tell you first hand that it is possible to ship a transmission to him via UPS in a wood crate. Mine weighed 135#... Good luck!

Re: 1951 Ford overdrive
 

The balk ring will generally be set up in the correct position when putting the transmission together so it will stay in position unless someone turns the output shaft while the solenoid is removed (not uncommon). Folks love to turn transmissions to see if they will go into all the gears. There is enough room in there for it to rotate past the two ears that keep it in the function zone. Those instructions will allow it to be rotated back into the zone in alignment with the operating pawl. If the balk ring doesn't have enough tension between it and the gear plate, it may just stay in the down position due to its own weight. This would make it difficult to get it to rotate up to align with the pawl bore.

Hopefully, yours has enough tension to allow it to rotate with the turning of the shaft. I haven't found too many that are sloppy loose. Most hold their tension pretty well. If it's loose it will make noise when the transmission shifts into overdrive. Your book should mention that in the troubleshooting instructions.

Re: 1951 Ford overdrive
 

My fingers are crossed. Thanks everyone. BTW, any comments regarding the synthetic Gl-4 lubricant originally installed in the transmission?

Re: 1951 Ford overdrive
 

Many will tell you not to use the synthetic lubricant for a lot of reasons. I've been running it for 45,000 miles all over the country. That's the only one I have to tell you it's ok but some will argue with that.

Re: 1951 Ford overdrive
 

This is a f/u to my ongoing struggle with the Borg Warner OD. As suggested in the citation pictured in one of my previous posts from the BW manual, the following steps were taken because overdrive would not engage:

With the OD t-handle pulled fully out, I rotated the driveshaft forward 360 degrees. I then loosened the cap screws holding the solenoid and withdrew it as far as possible. I held the solenoid in this position with a spacer and then rotated the driveshaft forward another 1/8 of a turn. I then re tightened the cap screws. When I later road tested the car, I was disappointed that the OD still would not engage. Obviously, I am concerned that when the unit was rebuilt something may not have been done correctly. On the other hand, as I mentioned previously the transmission and OD unit were initially filled with SYNTHETIC Gl-4 lubricant. This was switched, after about 70 miles, to Gl-1 after reading the following statement:

" And most important of all DO NOT use synthetic gear oil. It is too slippery and the sun gear will not engage. You will have to disassemble the transmission and get all of the synthetic residue off of the internal parts. That is not a fun task!"

I am wondering whether this may be a possible cause of the OD not engaging. While Synthetic Gl-4 may not cause yellow metal corrosion in the main transmission, it may lead to the OD malfunction.

Any thoughts or personal experience would be greatly appreciated.

Re: 1951 Ford overdrive
 

I sent you a PM earlier in the week. In it I suggested that you get in touch with a member of the Early Ford V8 club in your area. The club members are willing to help and have lots of knowledge and experience. I was willing to provide some contacts.

There are members close to you that perhaps can help or steer you to someone that can. Sometimes having another set of “eyes” on a problem is all it takes.

I never got a reply to my message.

Tom

Re: 1951 Ford overdrive
 

Tom,
Sorry for the lack of a response. I am 4 hrs away from the nearest v8 club. I have actually already spoken with some of the members re this and other questions. All were willing, but didn't have any answers to this specific problem. I do plan to contact Mac Vanpelt if I can't resolve this issue. I do appreciate your help.
Bill

Re: 1951 Ford overdrive
 

The sun gear does not care about oil as much as the one way clutch, at least according to what you saw on fifth ave. At least that is how I read it. If the one way clutch does not work you will not be going forward with the handle pushed in.