Brownies? Aux trannies? Dual transfer cases? 2 speed axles?

[stick_witch]

Hey guys! So I’m just curious who all out there has put a brownie transmission of some kind in their idi f series truck? I’ve got a 4x4 zf5 with 4.10s, but find myself wanting lower gears for maneuvering trailers (4lo with hubs free works for this too, but of course thats spinning the front drivetrain which isn’t ideal, but works), and i also of course find myself wanting a higher gear for the highway, since the 4.10s put me pretty high in the rpms at highway speed. Essentially, im interested in a 3 or 4 speed/5 speed dual stick setup in my truck. Ive heard of it being done in these trucks and in small toyota pickups and whatnot, but its all been hear say and not much more than that. So im wondering if any of you guys have done it, and if how did you set it up and with what did you set it up with?

 

[Garbage_Mechan]

Yes there are some brownie boxes that are under direct over. They are pretty scarse.
There is also the Mitchell 2 speed box that has been out of production a long time.
Probably the most discussion I’ve seen on them has been on the 4btswaps conversation forum. It covers a lot of diesel swaps not just 4bts.

 

[Clb]

I think goose is brownied up might be someone using duals (doubler) in crawlers ?cory?

A 3 speed box would rock (over,direct,under)
A 4 gear aux. Is gunna be a pain to track (old school 5\4 types.

My 83 toy rockcrawler has 20 gears from 5th hi down, the 22re squirrel would not like an od much.

Edit
Someone was building an mdt chassis setup under a 1 ton towpig 2 speed rear and all.

 

[Booyah45828]

I had a spicer 7041. Had 2 unders, a direct, and an over. It was a pretty massive transmission, as large as your zf, and being cast iron, twice as heavy. I was going to use it strictly for the OD in my bus, but sold it in favor of different rear gears. I run an automatic, and don't think I will have an issue being geared too low out back.

You'd have to have a lot of space under the truck to mount one, and you'd likely have to have it after the transfer case, meaning you could only use it in 2wd.

Is your zf5 the close or wide ratio? If it's the close, I'd look for and upgrade to a wide version or a zf6. That will give you a better reverse and crawler gear then what you have.

 

[Booyah45828]

And honestly, those aux trans aren't the most common thing out there, so I'd imagine it would be easier to find and install a different main box, then it would be to install one of the aux boxes.

 

[u2slow]

Some guys have 'reloaded' their ZF with the gas ratios. 1st and reverse are the most affected.

Not sure your wheelbase, but a std cab doesn't have a lot of room with the midship fuel tank. A gear-vendors sort of thing is probably the most compact option.

 

[stick_witch]

I had a spicer 7041. Had 2 unders, a direct, and an over. It was a pretty massive transmission, as large as your zf, and being cast iron, twice as heavy. I was going to use it strictly for the OD in my bus, but sold it in favor of different rear gears. I run an automatic, and don't think I will have an issue being geared too low out back.

You'd have to have a lot of space under the truck to mount one, and you'd likely have to have it after the transfer case, meaning you could only use it in 2wd.

Is your zf5 the close or wide ratio? If it's the close, I'd look for and upgrade to a wide version or a zf6. That will give you a better reverse and crawler gear then what you have.

Yeah, theres a couple of those on ebay. I’ve got an ext. cab with a long bed so theres a little room but not a ton. But ive seen guys put a 3 speed aux paired with their autos or 4 speeds in their f150s so i’d imagine it should be double, but i have no idea what they had for a 3 speed under those.

And yeah, i don’t mind it being just for 2wd anyway because theres gear reduction in the transfer case. The idea is to get gear reduction and overdrive for 2wd for towing and then for better highway cruising, which you can’t have both if you swap gears in the back.

I have the stock, diesel, “close” ratio gears in my zf5, and really i don’t want to touch those because i like the lower gears and the jump from 2nd into 3rd/4th/5th if i just swapped my drive gears would be too large for towing up hill and would be a bear. I already struggle with the jump from 2nd to 3rd hauling up steep, winding grades we have here in my town in AK, which is why a an aux tranny to split those gears would be nice.

The “close” gears were made for the idi, the “wide” ratio gears were for the gas trucks, and i want to keep it that way. A zf6 could be an option though. But, for the purposes of this thread i kinda want to stick to exploring the option of making a 15 or 20 speed setup in our trucks.


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[jaluhn83]

US Gear dual range / Doug Nash DNE2 box. In your application get an OD box (0.8:1) gives you the equivalent of a 3.28 rear in OD, or could regear to 3.55 and use an underdrive box to get the equivalent of a 4.43 rear in low.

Shifts like a 2 speed rear on either a pushbutton or push/pull switch, and is much lighter and all around easier to do than trying to cram another trans in.

Hard part is finding one, but they're around. Also, OE 4wd boxes (mount between trans & t-case) are very rare, however you can put a 2wd box (which is more common) behind a 1356 slip yoke t-case fairly easily, though it does still require machining a custom adapter.

 

[Isaac Ristow]

My 85 chevy C30 6.2 turbo 4 speed has a advance adapters ranger box waiting for it in my office. Its a direct, over 2 speed synchronized planetary that goes between the bellhosing and trans. They make them for ford and chevy but the trans has to have a removable bellhousing will NOT work on a zf5. So my c30 will have a twin stick 8speed. The ranger box is 7 inches long adjusting of the drive shafts will need done

 

[71 Highboy]

And honestly, those aux trans aren't the most common thing out there, so I'd imagine it would be easier to find and install a different main box, then it would be to install one of the aux boxes.

I have one in my shop like this from a bus that I owned, You are on point with all concerns. Not worth the effort on a 4x4 because of spacing and the 2 WD only aspect, not to mention U joint flange differences for the larger in and out shafts. Now a old friend did this with a smaller 3 sp over, under, direct in a bumpside and was getting nearly 27 mpg. He welcome to this boat anchor if serious. It has truck u joints now.

 

[BrandonMag]

I had two brownies at one point. Sold 'em both. The reason: once I had them in my hand I realized the work required to properly install either was just too great. I'm all for installing custom stuff on your truck, but installing an OLD non-synchronized auxiliary transmission that is rated for maybe 250 hp is just too much effort for little gain. (I forget exactly how old the brownies I had were, but I think one was from the 30s and the other was from the 50s.)

 

[Nugget]

US Gear dual range / Doug Nash DNE2 box. In your application get an OD box (0.8:1) gives you the equivalent of a 3.28 rear in OD, or could regear to 3.55 and use an underdrive box to get the equivalent of a 4.43 rear in low.

Shifts like a 2 speed rear on either a pushbutton or push/pull switch, and is much lighter and all around easier to do than trying to cram another trans in.

Hard part is finding one, but they're around. Also, OE 4wd boxes (mount between trans & t-case) are very rare, however you can put a 2wd box (which is more common) behind a 1356 slip yoke t-case fairly easily, though it does still require machining a custom adapter.

The US Gear Dual is installed on my truck, but need to double check its connections. It used a pull tab style button, i also have the manual for it. Be aware that they made the Over and Under boxes. One adding OD upper, so 1-1.5-2-2.5 etc. And the under, .5-1-1.5 etc.