I have a 79 D100 truck with 225 and three speed column shift. Does anyone know the name brand of the transmission and if Borg-Warner or Venture Gear, or anyone else make an overdrive unit for that transmission? Thanks. Tony

Chrytsler made a 3spd + OD for your truck called a 833OD. They are fairly common and a better trans than the 3 spd.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

for the price of buying an OD add on at $1k...you easily buy a Truck A-833OD, rods, shifter, shift stick, bellhousing, and tranny hump (it's floor shift).

You can use your clutch disc and plate...so everything is pretty much a bolt it...only real mod is the cutting of the floor and installing the hump fot the shifter...

I bought one of these front to back without the hump about 8 years ago for a grand total of $150-I pulled the parts out of a 1981 Dodge.

-D.Idiot

have found most folks are not aware of the existence or operation of the old style of overdrives on manual transmissions which was available on chryslers until 1959 and chevrolets and fords until about 1967. i think poster fopar is most familiar with them. i think that may be what this writer is asking about. borg warner made most of these american overdrives. the unit was actually like a 2d gearbox right behind the 3speed manual transmission. i had my last one in a 63 chevy belair 6 with a 3 speed . the units were complicated and somewhat trouble prone. usually the actuating solenoid would crap out . most had 3 characteristics: when in overdrive gear the final drive ratio would go up from 1 to 1 into .73 to 1 which lowered engine speed about 27% raising mpg and lowering engine wear. you would engage the od when cruising above about 28 mph. it wasnt of much value around town in stop and go. 2d it was semi automatic- you would push in a t handle cable under the dash which would engage the solenoid actuator for the od gear, but it would not engage until the engine speed reached 28mph when an ignition coil interrupter would momentarily stop torque and allow the od gear to go in. a 3d characteristic free wheeling would allow you to manually shift the 3 speed up or down without using the clutch, except when starting or stopping, when the t handle was engaged. some thought this novel feature was dangerous b/c until od kicked in you had no engine braking. you actually could get a 6 speed trans out of the manual 3 spd by engaging and disengaging the t handle above the 28mph od kick in speed( 1st, 1st od, 2d , 2 od, 3d, 3d od) . that was a lot of work , shifting, clutching and t handling but alot of fun if you were budget racing flathead ramblers at deadmans curve. anybody here been there? thought you might like this little digression into ancient history. paladin

Yep had that same type of OD on a 57 Ford 'vert I owned a looong time ago. That 292 got pretty good mileage in OD.

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65 Dart station wagon slant 6 - now under construction
47 Dodge Custom 4 Door sedan
87 D100 Short Bed slant 6

Retired USAF 1966-1986
Retired US Postal Service 2004-2014

Hey Bob, your memory is fading Not trying to be picky, but.
On the B/W overdrive units, the handle was pulled out to lock out the overdrive , and make it like a conventional 3 speed trans (non syncro 1st gear). When the handle was pushed in, it "enabled" the OD. After about approx 28 mph (as you said), you lifted off the accelerator, momentarily. That removed the load from the gearbox and allowed the upshift into OD.
If you needed, to downshift into "conventional" 3rd gear, just mash the pedal to the floor. There was a switch on the throttle, that would (can't remember the exact wireing/sequence of operation) work with the governor, and solonoid on the trans, and disrupt the ign circuit, momenteraly, and disengage the OD. I had several cars with them, and liked it. Just got rid of my last Chevy unit about 3 years ago. Also as you said it was possible to use the OD as a gear splitter. I did mine by moveing the Kickdown switch from the throttle to the shift lever.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
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64 Valiant 4dr 170
64 Valiant 4dr 225

A comment to Bob Fisher, without taking over this thread: That kind of history is essential, because most of the little tips and tricks were never written down. In an age where an internet search wouldn't bring any result because there are no texts to refer to, this is a very good way to document that kind of information. Someone needs that info one day - now it is there to find. I think that this forum is the worlds best, just because of such info from people that have been tinkering with cars and engines and accumulated knowledge that spans over several decades. Thank you, and keep the stories coming!

Olaf.

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Aspenized

Bob I still have the Ford 3 speed with overdrive unit, it is a cast iron case for both trans and overdrive.

Richard

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Part of Tyrde-Browne Racing

thanks to all the sages who added commentary to my writing. charlie s you are absolutely right, pushing in the t handle moved the od shift lever and pulling it out disengaged the od, but the solenoid would actually accomplish the shift when it sensed 28 mph. sorry if i wasnt clear on that. seems back in the day of heavy full frame cars little consideration was given to weight and mpg concerns. the optional bw od was a compensator to help mpg. most of the time i left my 63 in od. it would get 14 in town and 18 on the hwy, but in od it would get 18 in town and 26 on the hwy. a hidden savings which only cheap bastids might recall since it was not advertised was the clutch would last longer since you didnt have to use it as much. heres one ill bet nobody on the forum ever saw. uncle moe had a 50 dodge coronet sedan with the flathead six, but it had a 3 spd column shift with bw od and a fluid drive clutch. thought the car was a little dangerous. it was heavy and even when it was out of od it still felt like it free wheeled due to the fluid clutch. it was a bear to stop over 30mph. the owners manuals warned you not to use the od in hill country or in snow. always surprised me that these bw ods which go back to the early 30s werent replaced by 4 speed manual ods like the chrysler overdrive 4(75 and up). a lot more reliability and less complication. moe told me people were too dumb to avoid lugging the low powered engines ofthe era in od gear so the solenoid would automatically kick it out of od below 28 mph to save the engine. have commonly seen old timers ( especially ladies, now im in big trouble) ride clutches to avoid lugging and then ponder why the clutch only lasts 15k miles. it is easy to lug the chrysler overdrive4. actually the 38-39 vw beetle and all the rest of the beetles had a 4 speed manual od trans. so the technology was there. if ive missed any tidbits about the bw od please feel free to fill in. fopar you may be the last on the planet to have a working one on your garage floor, but ill bet the solenoid is dead. paladin

The Laycock overdrive as used on the Volvos is similar to the Gear Vendors units. These Volvo units (other makes used them too) could have an adaptor made for various transmissions, or I think these units can be separate from the gearbox. I would think there would be a vendor that made kits to use the Laycock, but I don't know of any Mopar supplier for laycock de normanville kits. THese are common in the salvage yards.

tim k - interesting comment about the laycock od. i only remember seeing one. didnt know they were the ones used in the volvo od which was a 4 speed with a 5th speed od gear button on top of the floorshift knob. later volvo did away with this electric od and went to a straight 5 speed manual with od 5th. the one laycock od i saw was an available option in the amc gremlin in its last years- 76 or 77. it was electric semi automatic with an actuating button on the end of the directional switch lever. the vehicle had a 3 speed floorshift. it kicked in at 28mph and free wheeled until the od kicked in but the od only worked when the shift was in 3d or high gear. no od in 1st or 2d. never heard much either way about the laycock design. since the 73-79 was the so called gas shortage crisis, american manufacturers seemed to be scrambling to put out gas mile champs with available parts and tooling. this was when chrysler had the dart lite and feather duster in 76 with a modified sl6 and the 4 speed od with the aluminum case. still have mine. paladin

My 54 Plymouth wagon still has the 3 speed with OD. 2nd and OD is a great gear for climbing steep hills. The carb down shift switch does two things-shorts out the ignition and turns off the shift solenoid. And yes you pull out the "T" handle to lock out the OD. And do not forget that with OD you get free wheeling....

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50 chrysler,54 Plymouth, 64 Valiant conv 4 speed, 66 Valiant V8 wagon, 70 Challenger R/T 440+6 conv 4 speed,80 Colt, 98 Neon ACR,84 Honda V45 Magna
Taking care of 57 300C conv,48 T&C conv. Missing my 67 GTX and 36 Ply coupe

Did Ramchargers come with 833OD's or just the granny low 4speeds?

Isn't there another 4speed OD out? I saw one in a V6 Dakota or D150 of late 80's or maybe 90 something?

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
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