Have not done it myself but they do make a kit that to attach one to a Muncie for around 3K and I'd have to figure for that kind of scratch it probably ain't a major project to assemble. I kinda wonder though if it really makes sense to use a Muncie in that combo though unless you're getting the OD unit used for small money.
When you buy a new one, they include all the parts necessary for that particular application, including a cast adapter that goes between the trans and the UD OD and replaces the original tail shaft. Sent from my VS835 using The H.A.M.B. mobile app
But for the cost of a new one, I think you could buy a pretty nice five or six speed transmission. Sent from my VS835 using The H.A.M.B. mobile app
I agree...it’s only an overdrive not a gear splitter. I have one behind my TH350 and it is nice to click a button to come in and out of OD. See what will fit...lots of options for 5/6 speed manual or even TCI offers a 6 speed auto.
I ran a Hone overdrive for a while, but that was about forty years ago. Back then three and four speed transmissions were all you could get in anything that had any real strength. But today there is a much wider choice of beefy modern transmissions with five or six speeds which makes a lot more sense. Unless you are restoring something to period correct, quick changes or bolt on overdrives are old technology.
Muncie 4 speeds and Borg Warner t-10 4 speeds, both have reverse gear located in the extension housing. Making any kind of adapter to attach a Gear vendors will be a MAJOR undertaking; a lot more than attaching one to an automatic transmission. I was thinking a Hone-O-Drive would be the better way to go; you do wind up with 2 drive shafts, one in front of the Hone, the other behind the hone. Both Ford and MOPAR have modified their 4 speeds into 3 speeds with a manual overdrive; that might be a better way to go. I am Butch/56sedandelivery.
This ^^^^ A WC T5 [Camaro] has a torque rating of 330 Ft/lbs vs 320 Ft/lbs for M21 And you can sell the M21 and you also don't need an external shifter for the T5 plus the 5 speed is easier to operate than a O/D
Wondered when somebody was going to mention the T5. There's a good thread here, I think it's called "ultimate T5" that explains all the variations of this trans. If your still curious about BW-Muncie type with an overdrive, lookup Doug Nash Corvette 4+3. A four speed with overdrive that was in mid '80's Vette.
Look at the Tremec TKO 5 speed trans. It will bolt to the same bellhousing as the muncie. Depending on which ratio you pick they come in 500 ft/lb and 600 ft/lb versions........about twice what a muncie can stand and that nice 5th gear overdrive is built in. Save the muncie and if you ever sell the car you can swap it out and keep the Tremec for your next project. Bout $2500 new
Another option. Did this back in the 70's https://www.jalopyjournal.com/forum/threads/adding-overdrive-to-saginaw-4-speed.647821/
Had a Doug Nash DNE2 behind a 4-speed in a big block dually. Splitting the gears was great, when you were heavy. Having an extra gear on top was fabulous on the interstate. Adapted a Borg//Warner R10 overdrive to fit behind the TH400 in my ramp truck. Improved it's road manners a lot, too. IMHO, unless you're going for nostalgia, a 5-speed is probably more sensible than an add-on OD.
The modern transmissions usually come with a choice of shifter location, so with a bit of research its possible to get something that should come pretty close to whatever vehicle you have when buying secondhand. If buying new you can just order it with the shifter where you want it.
The Tremec comes with multiple shifter locations. On older 4 speeds you had the added expense of buying a shifter that is mounted externally on the transmission. On a Tremec the shifting mecanism is built in to the housing. You do have to buy a handle though. There are three locations for the shifter . If you choose a location other than the one it's shipped with, then you have to buy an alternate mechanism too. You can pretty well get a location that is near where you need it.
Thanks I have a 55 chevy with a 4spd and I don't think I will change but just wanted to know.Had it since 74
I swapped out my 4 speed for a TKO 600 last winter in my 55 and its probably the best modification I have done. Silver State Transmission offered a shifter that would bring the new shifter up through the same hole in the floor as the 4 speed shifter. I opted to make a patch since the 4 speed hole looked like it was cut with a butter knife and bring the new shifter up in the middle of the tunnel. My leg always rested against the 4 speed shifter so I like the extra room.
It is not an inexpensive swap, but the problem with the older four speeds is they often break when used in a higher performance set up. When they break, it often will cost $700/$1,000 to put them back together. Basically thats what a used replacement will set you back. The Tremec most likely won't break unless severely abused with lots of Torque. The Tremec will make crusing much more fun with the overdrive. Often people are afraid to use their HP because they are afraid they might tear the four speed out. With the Tremec, much less to worry about.
Nobody's answered the OP's question. I can't, because I haven't done it. However, as some have pointed out, GV sell a unit with the necessary parts to mount it up to a Muncie: https://www.gearvendors.com/hrgm4sm.html As far as I know the GV overdrive is basically the old Laycock-de Normanville overdrive found on many British cars as well as Volvos and AMCs, with some crucial modifications. The cases and planetaries on these are plenty strong; their torque capacity is determined by the holding capability of the cone clutches inside the unit, which is determined by the operating hydraulic pressure. What GV have done is to increase the operating pressure drastically, by something like a factor of 3, so that the unit becomes capable of transmitting the sort of torque they do. You won't break the GV in this application, because if you have that much torque you'll have broken the Muncie first. This setup has a few advantages I can think of. First, shift quality. There are those who swear by the feel and shift speed of the old external-shift 4-speeds. I'd say that that is because the shift quality depends on the external shifter mechanism and not on the gearbox. You aren't stuck with the shift mechanism the gearbox came with, so the question of shift quality is open. By contrast I understand that the TKOs have a reputation for a bloody awful shift quality, and not much you can do about it. Second, most seem to think that the idea of the overdrive is a highway gear you engage after 4th gear. This misses the beauty of the thing. This combination comes into its own if you engage the overdrive at your first-second shift point, instead of second, and keep it engaged through subsequent shifts. That means that your crucial first shift is clutchless, under full power, and unmissable. It means your second shift is straight back, very quick, and hard to mess up. You might be going 110mph before you need to do a forward dog-leg shift. And in top you've still got the highway gear. To the OP I'd say, go for it. In a light car with a smallish screamer of an engine this would be brilliant.
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