Overdrive
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From: Reno, Nv
Overdrive
I have a 65 Ford F100, I've posted on here before and was told that the overdrive is engaged via a solenoid, looking on eBay and I see there is extra parts associated with this action. There is a pull cable, a kickdown switch, and then the solenoid. I'm concerned because my truck does not have the cable and I'm not sure about the kickdown switch. Is every truck supposed to have the above items?
Postmaster
Joined: Apr 2002
Posts: 3,613
Likes: 6
From: Coal country
Shane, I had the factory overdrive transmission in my '66, so I can speak to this transmission.
<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w
ontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--> There are 2 electrical parts mounted on the transmission. The larger one, slanted down toward the ground, is the OD solenoid. It should have 2 wires coming from it. Note that 1 wire is to activate the solenoid and the other is to hold it in via the kickdown circuit.
The second item on the transmission is the governor, mounted high and to the rear; it has 1 wire. It's function is to tell the OD system that the speed is high enough, usually about 30 mph, to engage.
There are several other parts:
The relay, mounted on the firewall, accepts the "go" signal from the governor. It also routes juice to the solenoid, for the 2 wires.
There is a kickdown switch under the accelerator, to temporarily cut out the OD for passing or more power.
There is a wiring setup on the distributor and coil to work in conjunction with the kickdown system.
You may need to get the wiring diagrams to understand and construct the wiring for the OD system.
Finally, there is a lockout cable with a "T" handle. This is designed to disable the OD function by mechanically locking out the sun and planetary OD gear set. Pushed in, the cable is inactive, and the OD can be activated. Pulled out, and the OD cannot engage.
The governor is required to activate the circuit. It grounds out the relay (on the firewall) to send current to the solenoid.
The T-85N in slightly different configurations was used by GM, Hudson, Nash, (all later AMC products in the '60s), but each manufacturer had their own requirements, but the transmission was essentially the same.
These OD transmissions have a nasty bite if you leave them in any gear except Reverse. They will ROLL! Leaving it in any gear except Reverse does NOT secure the truck.
The T-handle marked "Overdrive" does not engage the OD, instead, it locks it out and prevents it from engaging. This is useful for hauling heavy loads downhill, so that you can use the engine to brake - you cannot use engine braking with the OD, especially if the fuse fails.
When parking (or going downhill with heavy loads) pull the T-handle out, and leave it there, is my best advice, until you get in the habit of leaving it in Reverse. That OD handle locks the OD planetaries so it won't roll, but I still recommend you get in the habit of always putting the truck in reverse.
More Notes:
<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <wontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--> The 3 speed OD is not a regular 3 speed transmission with an OD housing bolted on. The 3 speed OD is a Warner T-85N transmission, and uses the Warner T-85 as it's basis, but the T-85N is indeed different from the T-85. Ford used Ford 3spds for their non-OD applications, and I believe (but am not sure) that the bolt pattern for the transmission to mount to the bellhousing is different.
The T-85N differed from the T-85 in that the output shaft, the idlershaft and the rear case bolt pattern drillings are all different. In other words, you cannot just bolt up an OD housing and go. It won't work. Additionally, you will require a different driveshaft length and type from the regular Ford 3 speed, as well as the proper bellhousing.
The 3 speed OD of this type requires more than just the transmission: It also requires the wiring harness which includes a relay, a kickdown switch on the accelerator, and a cutout on the distributor circuit to allow the kickdown to work.
Details can be found in the Ford Shop Manuals.
FIRST SEE MY DANGER WARNING FURTHER DOWN!
There are two electrical items on the T-85N: The upper one, on the passenger side, is the governor, and the lower one, on the driver's side is the actuation solenoid. You have a number of other items, so I'll describe them as well. This is, of course, a factory installation I am describing. If yours was transplanted, it may not be all there.
1. The governor closes the main circuit when the vehicle speed gets high enough, usually about 30 mph.
2. This activates a internally fused relay, which is on the firewall in the engine compartment above the main wiring harness port. The relay energizes the primary circuit in the solenoid.
3. When pressure is removed from the drivetrain by taking your foot off the gas momentarily, the solenoid drives home a pawl to lock in the OD sun and planetary gears. Once the pawl is in, an internal switch in the solenoid turns off the main circuit, and uses a less powerful circuit to hold the solenoid in. Thus the need for 2 wires. In other words, the way it works is this: Get up to about 30 mph, take your foot off the gas, listen/feel for the "clunk", and drive on at a lower rpm.
4. When the engine starts to bog down (because in high gear, a heavy load going uphill for example), your increasing pressure on the accelerator will activate a kickdown switch under it. This switch momentarily does 2 things: It kills the engine by grounding out the coil, and kills power to the solenoid. This allows the solenoid to drop out, effectively lowering the gears ratio, and giving you more power.
5. Occasionally, you will not want the OD to activate. While stopped, pull the handle under the dash marked "Overdrive". this engages a mechanical lever which internally locks out the OD, and keeps it in gear.
WARNING! WARNING!
THIS OD TRANSMISSION WILL NOT HOLD UNLESS IT IS IN REVERSE GEAR!
The OD unit has what is known as a overrunning clutch in it. That is, if the wheels are turning faster than the gears in the transmission, the wheels are allowed to FREEWHEEL.
This is dangerous because if the truck is in any gear but reverse, it WILL ROLL, even if it is in gear! ALWAYS, ALWAYS, get in the habit of putting it in reverse before you touch the keys.
I loaned my truck to my dad, and it rolled backwards, in first gear, with the door wide open. The door caught a tree, and bent the door pillar so far back the windshield leaks, and it isn't fixable.
Also, if you carry a heavy load, MAKE SURE your OD system is working. If not, pull the handle out, and live with the poor gas mileage. I had my solenoid die going downhill a number of years ago with 3000 lbs of stuff, which meant I had only my drum brakes to slow the truck down. I sure wish I had had disc brakes then for sure for sure!!! I burned up a set of brand new drum brakes that way, trying to stop, which I nearly didn't. When I say "live" with the poor gas mileage, I mean it. You may not otherwise.
Some other cautions: They have a tendency to leak, because the solenoid seal isn't good. Be sure to keep the transmission full.
When you change the fluid, let it drain for a while, and then when you fill it, let it sit for a while between checkings. The openings between the main gearbox and the OD unit are sometimes small, and the 90W gear oil may take awhile to seep into the OD part of the unit. Also check the OD unit for any extra fill or drain plugs and be sure to use them if they are there.
The overdrive relay is found on the firewall, just to the right of the master cylinder. It is between the master cylinder and the accelerator cable.
I have posted quite a bit on the Warner T-85N overdrive in this forum, and also in the '67 - '72 forum.
This is a series of notes that I posted here on FTE back in 2002.
Hope this helps.
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<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w
ontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--> There are 2 electrical parts mounted on the transmission. The larger one, slanted down toward the ground, is the OD solenoid. It should have 2 wires coming from it. Note that 1 wire is to activate the solenoid and the other is to hold it in via the kickdown circuit.The second item on the transmission is the governor, mounted high and to the rear; it has 1 wire. It's function is to tell the OD system that the speed is high enough, usually about 30 mph, to engage.
There are several other parts:
The relay, mounted on the firewall, accepts the "go" signal from the governor. It also routes juice to the solenoid, for the 2 wires.
There is a kickdown switch under the accelerator, to temporarily cut out the OD for passing or more power.
There is a wiring setup on the distributor and coil to work in conjunction with the kickdown system.
You may need to get the wiring diagrams to understand and construct the wiring for the OD system.
Finally, there is a lockout cable with a "T" handle. This is designed to disable the OD function by mechanically locking out the sun and planetary OD gear set. Pushed in, the cable is inactive, and the OD can be activated. Pulled out, and the OD cannot engage.
The governor is required to activate the circuit. It grounds out the relay (on the firewall) to send current to the solenoid.
The T-85N in slightly different configurations was used by GM, Hudson, Nash, (all later AMC products in the '60s), but each manufacturer had their own requirements, but the transmission was essentially the same.
These OD transmissions have a nasty bite if you leave them in any gear except Reverse. They will ROLL! Leaving it in any gear except Reverse does NOT secure the truck.
The T-handle marked "Overdrive" does not engage the OD, instead, it locks it out and prevents it from engaging. This is useful for hauling heavy loads downhill, so that you can use the engine to brake - you cannot use engine braking with the OD, especially if the fuse fails.
When parking (or going downhill with heavy loads) pull the T-handle out, and leave it there, is my best advice, until you get in the habit of leaving it in Reverse. That OD handle locks the OD planetaries so it won't roll, but I still recommend you get in the habit of always putting the truck in reverse.
More Notes:
<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w
ontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--> The 3 speed OD is not a regular 3 speed transmission with an OD housing bolted on. The 3 speed OD is a Warner T-85N transmission, and uses the Warner T-85 as it's basis, but the T-85N is indeed different from the T-85. Ford used Ford 3spds for their non-OD applications, and I believe (but am not sure) that the bolt pattern for the transmission to mount to the bellhousing is different.The T-85N differed from the T-85 in that the output shaft, the idlershaft and the rear case bolt pattern drillings are all different. In other words, you cannot just bolt up an OD housing and go. It won't work. Additionally, you will require a different driveshaft length and type from the regular Ford 3 speed, as well as the proper bellhousing.
The 3 speed OD of this type requires more than just the transmission: It also requires the wiring harness which includes a relay, a kickdown switch on the accelerator, and a cutout on the distributor circuit to allow the kickdown to work.
Details can be found in the Ford Shop Manuals.
FIRST SEE MY DANGER WARNING FURTHER DOWN!
There are two electrical items on the T-85N: The upper one, on the passenger side, is the governor, and the lower one, on the driver's side is the actuation solenoid. You have a number of other items, so I'll describe them as well. This is, of course, a factory installation I am describing. If yours was transplanted, it may not be all there.
1. The governor closes the main circuit when the vehicle speed gets high enough, usually about 30 mph.
2. This activates a internally fused relay, which is on the firewall in the engine compartment above the main wiring harness port. The relay energizes the primary circuit in the solenoid.
3. When pressure is removed from the drivetrain by taking your foot off the gas momentarily, the solenoid drives home a pawl to lock in the OD sun and planetary gears. Once the pawl is in, an internal switch in the solenoid turns off the main circuit, and uses a less powerful circuit to hold the solenoid in. Thus the need for 2 wires. In other words, the way it works is this: Get up to about 30 mph, take your foot off the gas, listen/feel for the "clunk", and drive on at a lower rpm.
4. When the engine starts to bog down (because in high gear, a heavy load going uphill for example), your increasing pressure on the accelerator will activate a kickdown switch under it. This switch momentarily does 2 things: It kills the engine by grounding out the coil, and kills power to the solenoid. This allows the solenoid to drop out, effectively lowering the gears ratio, and giving you more power.
5. Occasionally, you will not want the OD to activate. While stopped, pull the handle under the dash marked "Overdrive". this engages a mechanical lever which internally locks out the OD, and keeps it in gear.
WARNING! WARNING!
THIS OD TRANSMISSION WILL NOT HOLD UNLESS IT IS IN REVERSE GEAR!
The OD unit has what is known as a overrunning clutch in it. That is, if the wheels are turning faster than the gears in the transmission, the wheels are allowed to FREEWHEEL.
This is dangerous because if the truck is in any gear but reverse, it WILL ROLL, even if it is in gear! ALWAYS, ALWAYS, get in the habit of putting it in reverse before you touch the keys.
I loaned my truck to my dad, and it rolled backwards, in first gear, with the door wide open. The door caught a tree, and bent the door pillar so far back the windshield leaks, and it isn't fixable.
Also, if you carry a heavy load, MAKE SURE your OD system is working. If not, pull the handle out, and live with the poor gas mileage. I had my solenoid die going downhill a number of years ago with 3000 lbs of stuff, which meant I had only my drum brakes to slow the truck down. I sure wish I had had disc brakes then for sure for sure!!! I burned up a set of brand new drum brakes that way, trying to stop, which I nearly didn't. When I say "live" with the poor gas mileage, I mean it. You may not otherwise.
Some other cautions: They have a tendency to leak, because the solenoid seal isn't good. Be sure to keep the transmission full.
When you change the fluid, let it drain for a while, and then when you fill it, let it sit for a while between checkings. The openings between the main gearbox and the OD unit are sometimes small, and the 90W gear oil may take awhile to seep into the OD part of the unit. Also check the OD unit for any extra fill or drain plugs and be sure to use them if they are there.
The overdrive relay is found on the firewall, just to the right of the master cylinder. It is between the master cylinder and the accelerator cable.
I have posted quite a bit on the Warner T-85N overdrive in this forum, and also in the '67 - '72 forum.
This is a series of notes that I posted here on FTE back in 2002.
Hope this helps.
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Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 784
From: Simi Valley, CA
I have a 65 Ford F100, I've posted on here before and was told that the overdrive is engaged via a solenoid, looking on eBay and I see there is extra parts associated with this action.
There is a pull cable, a kickdown switch, and then the solenoid. I'm concerned because my truck does not have the cable and I'm not sure about the kickdown switch.
Is every truck supposed to have the above items?
There is a pull cable, a kickdown switch, and then the solenoid. I'm concerned because my truck does not have the cable and I'm not sure about the kickdown switch.
Is every truck supposed to have the above items?
Left: 6916 is the solenoid, 6919 is the governor.
Right: 7A200 is the O/D wiring harness, 7A650 is the cable, 7A651 is the relay, 7A652 is the kickdown switch.
Postmaster
Joined: Apr 2002
Posts: 3,613
Likes: 6
From: Coal country
In 2003 I sold my T-85N and converted to an automatic.
Before I sold it, though, I took a lot of pictures of the wiring and parts so the buyer had a reference to reinstall it.
If you want the pictures, e-mail or PM me with your e-mail I will send them to you.
Before I sold it, though, I took a lot of pictures of the wiring and parts so the buyer had a reference to reinstall it.
If you want the pictures, e-mail or PM me with your e-mail I will send them to you.
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