I ran the numbers with Elliott's Brownie ratios and a Ford three-speed. There is enough duplication that there are only seven distinct gears. With a bottom gear of 5.9, there is a good "grannie" and a top gear of .73 takes care of overdrive so you don't have to change out a ring & pinion. A five-speed like my Dana 540 would do about the same spread, with a direct top gear.
The advantages I see to the twin-stick setup (3-speed trans + 3-speed Brownie) over my 5-speed is that you have some split gears for those long grades and you have direct one gear down from top. I like to "float" in OD, but drop back one gear when pulling moderate grades in direct because that seems to be a big percentage of my pulling. The ability to have a simple three-speed setup when running unloaded is also nice. (With my Roadranger I will have to "skip-shift" every other gear to get the same effect.)
This all is a lot of fun to think about, but probably more trouble to put together than it is worth. The car lot I used to work on had this setup in a '54 Ford two-truck, so we are definitely talking "old school" here.
The Spicer that Elliot has sounds perfect for me. Honestly, it would probably stay in 1:1 most of the time and maybe use the OD to split when I need the extra gear while the 2:1 would be useful to start those heavy loads.
Archie; My thoughts are using either a T19 for full syncro, or I was hoping your NP540 was the D1 Model that is 6.06/3.30/1.59/1.13.1.00 in front of the Spicer 6041. If I did enough shifting, that woild give me (OD down).86/1.00/1.13/1.24/1/36/1.59. That would give me 12.97 in bottom gear.Course if you had a 205 behind all that, 4X4 low range would be 26.0, but if you weren't carefull, axle shafts and drive lines would go pop. My main problem right now is trying to figure out a way to move the transmission back aways, so the shift tower isn't in the dog house.
I was planning on putting the Spicer between a Clark 282 (6.99/4.09/2.17/1.17/1.0)and a NP205 which would give a low of 13.98 w/o the t-case and 27.4 with. The OD would fill in the gaps between 2-3 and 3-4 and provide an OD for the hiway.
I am very glad to have found this thread, very interesting stuff. I will contribute what I can at the moment.
The Doug Nash overdrive unit became the U.S. Gear overdrive. Differences between the two are gear teeth counts (U.S. Gear version has finer teeth) and pressure angle of the teeth. The U.S. Gear version is rated at a higher G.V.W. and has reduced backlash for these reasons. Also, the shift motors are wired differently, one switches power and ground between the two terminals, the other applies power to one or the other terminal and grounds to the housing. These shift motors can be replaced with two speed axle motors. The female input spline is 32 and the input mounting flange is the same as a 208 transfer case. This means if you take a 465 Muncie transmission from a 1981 and newer Chev. 4x4 with the long 32 spline output shaft (from a 208 transfer case application), and the 208 case adapter, you can bolt on a Doug Nash or U.S. Gear unit. A Turbo 400 also has a compatable 32 spline.
Just to let you know, Ford uses 31 spline output shafts in most cases and Dodge uses less. The 32 spline was the strongest one of the lot, the 208 T-case was common among the Big Three at the time Doug Nash made the first boxes, so adapters were already in existance. Further, the original application for these overdrives (or underdrive if that is what you wanted) was for two wheel drive applications, and adapters were available to replace the output yolk of the transmission to adapt various transmissions to a 32 spline output. Incidentally, the output of these overdrives is made to accept a Turbo 400 bolt on driveshaft yolk.
I will post a listing of the Spicer 5531 and 5831 model designations and corresponding ratios soon.
My idea of a truck driveline is a Ford 300 turbocharged, aftercooled on propane (blow through) with 465 Muncie/Doug Nash overdrive and 4.10 gears (3.28 in over). This one is a current project.
Also have a Perkins 354 with 4 spd. and Spicer 3 spd. with overdrive that is waiting for its installation in something.
There's a 1967 Chevy C20 that i'm working on right now. It has a plain old 2bbl 350 and a SM420 in it right now, but the guy that owns it has a NP 5 speed with a spicer 3 speed box mated to it sitting in the corner of his garage.
The intentions are to swap the 5 speed and 3 speed into the truck to have a haul vehicle that can actually keep pace on the highway. Only issue as of yet is going to be how to get a 3/4 ton driveshaft hooked to the back of the Spicer box.
Right now it has about a 6" round flange on the back, so the intentions are to make a matching flange and then drill it to accept a 3/4 ton double cardan flange and then use a 1 piece slip shaft driveshaft instead of the 2 piece.
But this too leads to another issue. The C20 is coil sprung out back and the carrier bearing crossmember is what the trailing arms bolt to. . . Ahh projects, so much fun
The best part of these forums is that one can have the fun, without having to do the work. (Then there are those who say "It can't be done!" Then you have to do it to set them straight.)
Spicer makes a lot of U-joint yokes, some of which are flanged. Their catalog is down-loadable in pdf format. I just bought a Spicer yoke from Drive Line Service in Las Vegas - great service.
Is your 5-speed a NP-540? Is the Brownie mated with an integral adaptor, of with an open short driveshaft?
When I install my Roadranger, I am hoping to go with a one-piece driveshaft, but I am right at the limit of practicality. (I have a technical article that goes into ALL the calcs that are used to determine allowable safe driveshaft lengths - if anyone is interested I'll post the URL.)
Because this is FTE, I should point out the cure to your trailing-arm problem, but I guess you know what it is . . .
Yeah, i know there are alot of yokes and I have their catalog. It's just a matter of for what they want for the yokes, i can machine the adapter in my garage and be very much ahead.
The trannies are directly mated. They have what look like two soup bowls and the rims bolt to one another. As for the trans, i don't know the exact model. all i know is that it's a 5 speed new process with a 1:1 top gear that came out of a GM cement mixer and it was behind a 366.
I'm heading out to the guys house tonight to start taking measurements to see exactly how this is all going to fit together.
newbie to site. hope i do this right. I have a model 42 brownie. don't know ratios. is 3 speed. about one quarter turn difference between imput and output shafts in all 3 speeds. am planing on mating it to a divorced T200 transfer case. have the connector shaft and shift linkage for both gear boxes. looking to mount this in a 1952 army truck frame and putting a lincoln body with a 429 or 460 for power. not a truck or a car either. may not qualify for post. Jr Watts
Allow me to be the first to welcome you to this thread and to FTE.
It sounds as if your quarter-turn difference would be right for the overdrive gear, but the other two would probably be a direct gear and a much lower gear. You should to do a careful experiment to find out which trans you have. I suggest you chalk a mark on the input & output shafts (or yokes), then rotate the output shaft ten turns and count the turns of the input shaft. (This is a lot easier to do with two people, especially if both avoid counting out loud.) All you need to do is divide the the output numbers by ten and you will have a fairly accurate idea of the ratio. Do this for all three gears and you will have a better idea of what you have. Post your results on this thread as well as what transfer case & axle ratios you are using. It looks as if you will have a good double reduction rock crawling gear, plus perhaps an overdrive to help gas mileage out on the road.
As far as I can see you may have a car body, but your running gear will be all truck. As long as you have a "Brownie" or another auxiliary trans, you are welcome to post in this thread to discuss it and what it is installed in.
Hello all, my first post here. I have to say, this is one of the best threads on the 5831 I've found so far among all the forums I've looked at. So here is my story:
I have a 1968 M-715 military Jeep, (check out The M715 Zone - Powered by vBulletin for more info if your curious). All stock drivetrain: 230 inline six with T-98 with a divorced NP200 transfer case. Front D60 and rear D70 with 5.88 gear ratio. Long story short, the only other gear ratio available for this version of the D60/70 is 4.56, but I really like the crawling gears.
This vehicle is pretty much just a play rig for me, although I've been building it up over the years to serve as my primary vehicle for Search and Rescue operations, as I am a member of a local SAR Jeep Patrol group.
So I really wanted an overdrive to help for highway driving, as well as so more gear choices. Plus I'm like some here, and just want to have fun with this rig and do something "unconventional", although in my opinion this rig will be one heck of a fun thing to drive when I'm done. I found an old vintage Warn Overdrive unit that was married to the back of a T-18 transmission (Warn also made an overdrive unit that married to the back of the DANA 18 transfercase, but this is most definately not remotely close to the same type of unit). So my plan was to swap the T-18 output shaft into my T-98 and marry that unit to it. It is fully synchroed 1:1 or .75:1 ratio via a planetary gearset inside.
I both was worried about the strength of this old Warn unit, as well as the fact that I have some future plans for my 715, so I didn't want to go with a unit married to my T-98. So I found myself a Spicer 5531 with no letter after it. 2:1 low, 1:1 direct, .73:1 overdrive. I am in the process of figureing out how to fit this big box into my drivetrain.
My current dilemma is the fact that I want to put it between my transmission and transfercase. Besides the fact that I have to scoot my x-fer case back at least 25", I was wondering what the best way to connect the T-98 to the Brownie, then to the x-fer case. I have long enough wheelbase that I won't have problems with a short rear driveshaft, and I'm not worried about going with a 2-piece front shaft, but I want the connections between the boxes to be absolutely as short as possible, every inch is precious, lol.
I found this site where a guy married a Brownie to a T-8/9 transmission, really cool. Untitled Document
Not sure if I want to do that, so here was my idea. I'm thinking of going with u-joints (haven't decided on series yet, not sure if 1310 is going to be strong enough) and use "H" yokes, or the double u-joint yokes they use sometimes for high driveline angles. So I'll go T-98 yoke to u-joint to H-yoke to u-joint to 4-bolt flange yoke on Brownie. Other side is same to the input of the NP200. This way I will have a very short connection, but allow some flexibility if I don't get my boxes perfectly concentric with each other. I'm not worried about not having a splined shaft because the stock M-715 has a non-slip shaft between the T-98 and NP200 right now, and its never been a problem. I'll put rubber mounts to allow for any other misalignment.
What do you guys think? I've just never seen a Brownie actually installed in a rig, so I don't know what they used in stock form. Although I bet that most of even the heaviest hauling rigs weren't 4wd and concerned with short wheelbase, so they probably just had a good sized d-shaft between transmission and Brownie.
My future plans for the 715 is a 6BT with Spicer 3053A 5-speed transmission. I'd like to keep the brownie even with that, double overdrive is going to me nice. And yes, I've read the other thread regarding the Roadranger transmissoin, I would go with that if I could get my hands on one, I think it would be easy to bolt with an SAE bellhousing to the Cummins motor. And if you think I'm not crazy enough, I did at one time almost put a 4-53 Detroit in my rig. I have the Detroit, just couldn't find a bellhousing/transmission to mate to it. So I think I'm going with the 5.9 cummins route eventually.
sarm715, Welcome to this thread and to the FTE forum.
My first reactions are that 1310 U-joints are probably fine for the front drive shaft ahead of the auxiliary trans with a 230 six. Behind the auxiliary the torque will be double and behind the T/C it will be doubled again, so even big U-joints will have problems if the driver is not careful.
The other thing is in regard to using U-joints in any application that does not give them at least one degree of "exercise". If the needle bearings do not move at all, they will Brinell into their races, forming grooves into their races and failing early. I would either recommend a machined co-axial rigid-coupled setup without U-joints or a short shaft with the auxiliary installed parallel to the main transmission, but offset enough to give the U-joints some exercise. The Brownies I have seen usually had a two-foot shaft in front of them.
Also, unless there is something special to your D60 & D70 differentials, I think you are limited to the gear ratios you have mentioned if you only replace the R&P, but can go to 3.54, 3.73, & 4.10 if you change out the differential carrier when installing the gears. This is not necessarily easy or cheap, but that option is there. If your diesel plans come to fruition, you may need more than just an overdrive to get much top speed out of a low-rpm diesel.
Last edited by acheda; 04-30-2008 at 10:15 PM.
Reason: grammar . . .