hey has anyone ever tried putting an old skool 3spd "brownie" box behind a c6 for more gears/overdirve/puller? just wondering was going to try and find one and try it. if anyone has any tips or anything

 

aww come on guys someone has to have thought of this or even done it b4. or atleast have some imput

 

I have heard about those brownie boxes. Today people are using Gear Vendors over/under drive units.

I saw posted somewhere on this site something about those brownie boxes. Try a search.

 

well i would love to have the money for a gear venders unit but i dont. also a gearvenders unit is only an overdrive or underdrive not both with a "brownie" box u usually have 3 gears over under and direct but thanx for the reply

 

You are welcome. Like I mentioned above, try a search. I saw something about brownie boxes on this site somewhere. As a matter of fact, I never heard of a brownie box until I read about it on FTE.

 

Is this for your pickup with C6 auto?

From my understanding, the Spicer brownie boxes only work with a manual trans because they need a clutch to disengage the power so one can shift it. It shifts with a stick like a manual transmission. They also usually mount between the bellhousing and the main transmission. There were 5 ratio sets made for it:

1.54, 1.00, 0.73.
2.35, 1.00, 0.85.
2.00, 1.00, 0.73.
1.27, 1.00, 0.73.
2.00, 1.27, 1.00.

Here are some other gearing alternatives:

There is an auxilliary range box called a Ranger Torque Splitter, sold by Advance Adapters, that comes either as a 17% underdrive or a 27% overdrive, not in the same unit. Unfortunately, it is also used only with a manual trans and also goes between the bellhousing and main trans. These cost about $1500. Check out www.advanceadapters.com.

The Gear Vendors is an overdrive only and can go behind an auto or manual. It has planetary gears like an automatic and can be shifted under power and without a clutch. On a 4x4, it goes after the transfer case and only operates in 2wd by way of a lockout switch. These units cost about $2500. Check out www.gearvendors.com.

US Gear also makes your choice of an underdrive or an overdrive, not in the same unit, with ratios similar to the Ranger trans described above. It is reportedly a Doug Nash design that US Gear bought out. It is built like a manual transmission but can go behind an auto or manual and is shifted by electric switch. These units cost about $2500. Check out www.usgear.com for more info.

Another choice for an underdrive is an the low range box from an NP203 full-time 4wd transfercase. The gear reduction box was a seperate box from the 4wd section. These boxes have a 2.02 low range and offroaders have been putting them between the main trans and the transfer case as a 'doubler' gear, for a super-low crawling ratio together with the normal low range in the truck's own transfer case. I don't know if there is a way to hook a driveshaft to the back of it for use in a 2wd though. Might be worth investigating since used NP203 t-cases aren't too costly and they were used behind most popular truck transmissions, both auto and manual, in the 1970's so there are adapters available for them. I dont see any reason why you couldn't convert it to part time and just use the whole transfercase and just don't connect a front driveshaft to it

One gearing idea I was thinking about today was using a Spicer 18 4wd transfer case. The model 18 has a 2.46 low range and there are aftermarket gear kits for it that give it a 3.15 low range. The cool thing about the Spicer 18 is that it can be used together with a Saturn Overdrive that goes in the back of the transfercase and offers a 0.75 overdrive ratio. The kicker is the rear output yoke is offset to the passenger side, so it would require a custom rear axle with an off-center differential housing, like a common 4wd front axle. You can read about the Saturn Overdrive and Spicer 18 t-case on the Advance Adapters site. I remember these transfer cases with the offset rear shaft and twin stick shifters in the old *****'s and Jeep CJ's.

Another route to take would be to swap in an NV4500 5-speed which has a 5.61 'granny' first gear like the old heavy duty truck 4-speeds (NP435, T18, SM465, etc.), but also has an overdrive 5th of 0.74. These are iron cased transmissions with seperate bellhousings like the 4-speeds and there are alot of adapter kits available to put them behind various American engines and in front of various popular 4wd transfer cases as well. They are similar to a ZF 5-speed in gear ratios and application but are more easily swapped than the ZF, due to the ZF's one-piece case/bellhousing that limits what engines it can go behind.

That probably didn't answer your question, but might spark an idea for a possible solution.

 

While I have not done a brownie conversion, I did have an older friend that did. He had a Chevy Longhorn, early 70's w/TH400. Put a 3sp brownie in and it worked great. You shift using the throttle. Ease up on the throttle so there is no torque on the drivetrain, make the shift and walk back on the throttle. These were non-syncro trannies. BTW a truck driver or ex driver would know exactly how to shift the combo

 

well thats what i was thinking ive driven nonsyncro sticks b4 and u really dont need the clutch other than to get moving somtimes to downshift but rarely. and thanx for all the info might look into the "doubler box" and a higher rear end well anyways enough babbling, now its time to get to work, or maybe more studing

 

An old post I realize, but I saw a 1968 Highboy with a gear splitter in it today and it didn't look anything like the advance adaptors units. This unit fit between the trans and the bellhousing and used an electric shift. The exterior housing was rounded and had aluminum fins running the length of the unit on the bottom. The tag was on the drivers side and I could only make out the last four letters of the manufacturer, it said *****SHOT. An old cowboy, the owner of the truck, kept calling it brownie and said that it was 17% overdrive and the unit was 8" long.

I'm pretty sure he just used that name as a generic term.

Does this sound familiar to anyone?

 

I have a Muncie 3 speed that I build a bearing nose for the input and was going to run it as an underdrive here a while back.....I am now contemplating mounting in behind my 435 and driviving the output shaft giving me 3 more gears. I will let you know how it works.