"Brownie" box

[lessersivad]

Well this is no where close to Festiva related other than is has 4 wheels.

I was just wondering if anyone on here has had any experience with an auxiliary transmission or "Brownie" box. I have the chance to buy one locally and I'm thinking about getting it for an install into my '85 GMC K2500. I know I wouldn't be able to use the overdrive in 4X4 but I thought it would be a nice feature to have for long cruises. The truck has 4.10 gears with an SM465 4 speed granny in it so I thought instead of trying to swap transmission I would just add one...LOL. The brownie has an underdrive of 2.00:1, direct 1:1, and O.D. of 073:1.

Here's a vid of one in action. The red handle is the brownie shifter.

http://www.youtube.com/watch?v=4a8SNT3uy-4

Any thoughts or suggestions are welcome. Thanks.

[blkfordsedan]

My Father had a Brownie over/under in his truck. It was an '84 Ford F250 extended cab. He used it to scrap iron in a 39Ft triple axle covered trailer back and forth between Phoenix and Nebraska. He boxed the complete frame, added supports and installed a 3208 CAT V8 diesel with twin turbos. He had a twin disc clutch, 5SP trans (not sure what it was out of), Brownie over/under and 2-speed air shift dually rear end out a Ford tilt-cab truck (he had problems bending the axle tubes on a std. 1-ton rear end). Later on, he moved the rear end forward and added a tag axle behind it. With all the available gear ratios and the torque output of the 3208 CAT (500+ LbFt naturally aspirated), he rarely took the Brownie out of overdrive. He just used 3rd through 5th on the tranny and the 2-speed rear end. The extra gears, however, were nice when pulling loads through mountain passes.

The F250 4X4 in my sig has an Eaton 2-speed electric shift (direct + over). It's out of a big truck as well, and about 5X heavier duty than it needs. I believe the overdrive ratio is about .83 if I remember. The truck has a Mercedes OM352 6Cyl turbo diesel, the old Mercedes UniMog's used the same motor. I have the std Ford 4Sp trans w/granny low and the integral gear drive transfer case. The Eaton sits between the output of the transfer case and the rear end (only used in 2WD). The driveshaft between the transfer case and the Eaton is basically 2 u-joints welded back-to-back. The motor is pretty guttless by today's standards and is designed to run @ 2750 rpm max. I really like having the extra gears because it allows me to stay in the powerband. Without it, the truck accelerates like a bicycle with flat tires. I also have 4.10 gears, so I need the overdrive to be able to cruise at 65MPH. I have to run LT245/75R16's to keep the motor in it's power band. I tried LT265's, but they were too tall for the 4.10's and the motor would lug and make the pyrometer climb.

So, based on my experiences, here's my thoughts on your application...............
You already have granny low, 4.10's and a low range on the transfer case, so the 2:1 under on the Brownie would rarely be used. Assuming you have a gas-burner, or even a modern diesel, you have plenty of power so "splitting gears" would serve no purpose other than being fun to drive. Unless, of coarse, you are pulling heavy loads over steep grades. 80% of the 12 different gears you would have will offer no discernible change in RPM or speed. My guess is that you will mostly use 2nd-direct, 2nd-over, 3rd-direct and 4th-over. I don't know what model Brownie you are looking at, but you'll be adding more rotational mass, internal friction and maintenance. Plus, like me, you will only be able to use it in 2WD. If you do pull trailers, you need to make sure the unit has the capacity to handle the heat and load of the application. Personally, I would trade my Eaton for a 5SP tranny any day. I just don't have the motor to run without it. If I ever swap in a gas motor, the Eaton will come out.

[lessersivad]

WOW! Thanks Brian. The unit I can get is a Spicer 5831. The GMC engine is a 6.2 diesel. No where close to a power house but it does OK. The split shifting would definately be different. While I was hauling a car for a friend of mine earlier today I was telling him about the brownie. He hadn't ever heard of the setup, (much like me till yesterday). I showed him the video and he just laughed and said it would be different from anything he's ever seen. You are probably right about the gears I would use most of the time but it would be nice to have the option of ultra low in 2 WD if needed. I'm suppose to get hold of the guy again tomorrow and ask a few more questions so we'll see. Thanks again.

[blkfordsedan]

WOW! Thanks Brian. The unit I can get is a Spicer 5831. The GMC engine is a 6.2 diesel. No where close to a power house but it does OK. The split shifting would definately be different. While I was hauling a car for a friend of mine earlier today I was telling him about the brownie. He hadn't ever heard of the setup, (much like me till yesterday). I showed him the video and he just laughed and said it would be different from anything he's ever seen. You are probably right about the gears I would use most of the time but it would be nice to have the option of ultra low in 2 WD if needed. I'm suppose to get hold of the guy again tomorrow and ask a few more questions so we'll see. Thanks again.

Yeah, the 5831 looks like it is an old unit that was originally used in bigger trucks. I looked it up on the internet. Physically it looks to be the same size or slightly smaller than the 2-speed Eaton I have in my truck. It would be PLENTY stout for what your doing (actually an overkill like mine is). I don't like the way the unit hangs so low on my 4X4. If I actually had enough power to go off-road, I would get it high-centered on the Eaton. That's something you may want to consider. The Brownie unit my dad had was a stick version like the video, but my Eaton is an electric shift with a push-pull button mounted on the regular transmission shifter. All you do is pull the button up, let up on the gas slightly and step back down on the gas and it shifts into overdrive. Going back down to direct (i.e. shifting from 2nd-over to 3rd-direct) is a little tricky, you have to develop a feel for it to keep from grinding gears. Since you have an older 6.2 diesel, I would say go for it. I think you'll really like being able to find the perfect gear. Since it does have an under-drive, you may be able to run some bigger tires that would normally kill the power of the 6.2. You could stay in under-drive all the time and then shift into direct or overdrive on the highway when you get it wound up. Let me know how it works!