Guest Crahm Posted March 8, 2016 Share Posted March 8, 2016 (edited) I have the "second type" of overdrive transmissions in my '41 Hollywood. On the left hand side of the transmission is an electrical device. What is the purpose of this? It is not mentioned in the Graham Owners' Repair Manual nor is it in the wiring diagram.thanks,Charles RahmDallas, TX Edited March 8, 2016 by Crahm (see edit history) Link to comment Share on other sites More sharing options...
Matt Harwood Posted March 8, 2016 Share Posted March 8, 2016 Overdrive solenoid? Governor connection? Back-up light switch? What does the device look like? A photo could probably get you the answer pretty quickly. Link to comment Share on other sites More sharing options...
alsancle Posted March 8, 2016 Share Posted March 8, 2016 When you say "second type" of overdrive what do you mean? The factory did not offer an overdrive transmission and because of the small tunnel no other transmission will fit. Some pictures would be interesting. Link to comment Share on other sites More sharing options...
Guest Crahm Posted March 8, 2016 Share Posted March 8, 2016 According to the Graham-Paige Factory Service Manual, for 1935-1941 Grahams, there were two types of overdrives offered for Graham cars.On page 57, the overdrives are discussed and described as "first type," used in models 86, 87, 88 and 89; and the "second type" used in later cars. According to the drawings in the book, my '41 has the second type. However, it doesn't discuss any type of electrical device on the side of the transmission. It would not be a reverse light as the car is not wired for one. This evening, I'll snap a photo of the device and try to trace the wires. My guess is either a kick down (out of overdrive) or some kind of electric governor. Again, the manual, when discussing the factory overdrives, doesn't discuss an electrical device as part of the system. Now that I'm thinking - I had an earlier post asking about a micro switch mounted on a bracket behind the carburetor. It was in a location where my thought was it could only be operated by someone's finger, but if it rotated on the bolt mounting position, I wonder if it was a kick down switch if you put the pedal all the way to the floor. Another item I'll examine this evening. Link to comment Share on other sites More sharing options...
alsancle Posted March 8, 2016 Share Posted March 8, 2016 Interesting. Remarkably, I have never seen or heard of a Hollywood with overdrive. Is there a dash switch to actuate it? All Hollywood's need overdrive because of the rear end gearing but my understanding is that the transmission won't fit. Maybe Tom Mulligan will chime in. Would love to see pictures and casting numbers. Link to comment Share on other sites More sharing options...
Matt Harwood Posted March 8, 2016 Share Posted March 8, 2016 I'll bet it's a Borg-Warner overdrive unit, and if it was a factory option, there would be both a governor and a kick-down switch as part of the unit. The solenoid would be a big cylindrical piece bolted to the side of the unit, about the size of a beer can. I'd love to see photos. Link to comment Share on other sites More sharing options...
Guest Crahm Posted March 8, 2016 Share Posted March 8, 2016 Attached should be two photos of the 1/2 beer can sized device. There was undercoating on it and I scraped it off. I can't see any markings or numbers on the device.There is one wire connecting to it.According to the Graham manual, the cable control under the dash is a push-in the cable for automatic engagement of overdrive at 40mph. A cable pulled outward prevents the overdrive from engaging.I'm now convinced the micro switch on a bracket built off the carb/air filter bolt, is a switch for full open throttle. My throttle linkage has an adjustable screw on a small bracket to the side of the throttle linkage. Mine isn't lined up quite right, but I think at wide open throttle, it was designed to close the micro switch, allowing power to flow through the device on the side of the tranny (tracing wire).Thoughts? Link to comment Share on other sites More sharing options...
alsancle Posted March 9, 2016 Share Posted March 9, 2016 I talked to the Graham club's Hollywood expert tonight and he corrected me. There are about 15 known Hollywood's with factory overdrive. He said that they were in fact mechanical not electrical. You learn something new everyday. Does your car have a coffee can sized hump between the gas pedal and the seat jutting out from the transmission tunnel? Link to comment Share on other sites More sharing options...
Matt Harwood Posted March 9, 2016 Share Posted March 9, 2016 The "1/2 beer can" is the solenoid that activates the overdrive. The push/pull cable on the dash is for the free-wheeling mechanism that is required for overdrive operation. The microswitch on the carburetor kills power to the solenoid at WOT, dropping you out of overdrive, much like a kick-down linkage on an automatic transmission. Once you let off the throttle, it would automatically drop back into overdrive. It is definitely not a purely mechanical system, it appears to be a standard Borg-Warner overdrive that was used on dozens of brands from the late '30s through the '50s. The solenoid only has one wire because it uses the transmission itself as a ground, so that wire is only supplying power to engage the solenoid. Do some Googling on the Borg-Warner overdrive and you'll find a ton of information and manuals on its operation. Parts are readily available and the gearboxes themselves are quite durable, but the solenoids can be problematic after all these years. It's a great addition to your car and will really transform its performance on the road! Link to comment Share on other sites More sharing options...
alsancle Posted March 9, 2016 Share Posted March 9, 2016 He was pretty clear that the original setup was mechanical. It is possible that this was added later in the car's life. Of course, since I didn't even know there were any factory OD cars I can hardly talk definitively over what this unit might be. Since I have only sat in my car and never actually driven it I'm also can't speak from first hand experience on this, but my understanding is that the biggest impediment to going fast is not the engine RPM. The biggest problem is the front fenders have no support in front of the wheels and grab the air. They start flopping all over the place. Hopefully something that some discrete reinforcements can correct. Link to comment Share on other sites More sharing options...
plymboy Posted March 9, 2016 Share Posted March 9, 2016 Hi Charles...I'm one of the tech advisors in the Graham Club for the Hollywoods...if you have any questions about your car I will try to answer them 520 351-2351..Tom Mulligan Link to comment Share on other sites More sharing options...
Guest Crahm Posted March 9, 2016 Share Posted March 9, 2016 Wow! Thanks for the thoughts and answers!I've attached a photo of the Micro Switch. The shiny pin which lines up with the screw on the throttle linkage is the actual switch pin. When I received the car, the bracket wasn't lined up and was turned 90 degrees which really left me puzzled. In the photo there are no wires hooked to it, but one wire was hot from the voltage regulator and the other goes down to the solenoid on the overdrive.The manual also says the overdrive transmissions use SAE70 oil for summer driving. I ordered some Lucas 70 from Amazon. I've never seen 70 weight but apparently alcohol racing engines might use it as well as some motorcycle engines. Link to comment Share on other sites More sharing options...
alsancle Posted January 5 Share Posted January 5 On 3/8/2016 at 8:38 PM, alsancle said: I talked to the Graham club's Hollywood expert tonight and he corrected me. There are about 15 known Hollywood's with factory overdrive. He said that they were in fact mechanical not electrical. You learn something new everyday. Does your car have a coffee can sized hump between the gas pedal and the seat jutting out from the transmission tunnel? There is a factory overdrive Hollywood on BAT right now. If you want to laugh read the comments where I'm asking where the "15 factory overdrive" number came from and eventually we figure out it came from me above. https://bringatrailer.com/listing/1941-graham-hollywood-supercharged-6 1 Link to comment Share on other sites More sharing options...
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