The Stovebolt Site Forums The Shop Area Engine Shop Can anyone ID this Brownie and explain ratios?

Finally found an Auxiliary Transmission for my 51 1-ton GMC The tag is missing. I was hoping someone could identify the tranny and help me figure out the ratios.

The Box weighs about 100 lbs. Looks like it holds about 4 pints of oil. Front and rear gears are beveled, center set are spur. The stamped date show in the pic is 1967.

Fiddling with the linkage and spinning the yokes I came up with a .79 over, a neutral, a 1:1 and a 1.26 under. Then I had to pull the cover to confuse matters. Towards the front of the box a 19 tooth gear on the upper shaft meshed with a 24 on the lower shaft. (.791:1) Then middle set was 24 teeth upper and lower. The back set was 17 upper and 26 lower which works out to .653 or 1.53. I can't figure out how I get a 1.26 underdrive when I spin the yokes, unless it is a four speed with a 1.52 under and a 1.26 under and a .79 over.

Please splain it to me.

I have posted a picture at

http://oldgmctrucks.infopop.cc/eve/ubb.x?a=tpc&s=272004236&f=633004236&m=829109747

but have not gotten any replies.

Thanks for your help

Sidehill

I couldn't see the picture. It wants me to log in. Maybe they don't allow direct linking.
Someone here should know about your overdrive.

Interestin looking piece--fraid my knowledge of these is quite limited, but seems like the gear count is twice the 1.26 underdrive--must be a half reduction on gear size or by gearing on that terminal set. Get some real grunt out of a rig like that. Do ya know what it came off of???

There's several models of Spicer auxillary 3 spd transmissions,if that's what yours is.Spicers generally have a raised top cover with the shifting gizmo.A common model is 5831B, low range is 2.35, direct and a .85 OD

Thanks for the input guys.

I don't know what my unit originally came out of. I had heard that spicers were rounded on the top and that the older Brownies were flat topped, like mine. However mine has beveled gears and I had heard that Brownies were spur gear and the newer Spicers were beveled.

I'm familiar with the great tranny website http://www.6066gmctrucks.org/SM420.htm and would highly recommend a visit.
I'm not sure what the timeline or mechanical difference is between Brownies and the Dana/Spicer Auxiliary trannies. Many of the units have plates that are stamped Brown-Lipe and Spicer.
I've also heard that the newer Dana/Spicer units increased in size with the series. 6000 series is larger than the 5000 series.

My tranny is smaller than a 6000 series that I've seen.

Thanks again

I've got a factory manual that's probably got the info you need, but couldn't get to where your picture is posted.

Could you post a diagram or sketch here?

Hopefully you'll see the pic of the brownie below. If not, see the next reply. [img]http://oldgmctrucks.infopop.cc/eve/ubb.x?a=tpc&s=272004236&f=633004236&m=829109747[/img]

I tried to post an image of the brownie using the Stovebolt instructions but to no avail.

I don’t think you should have to log on to the OldGMCtrucks site to view the forum.
You should be able to get into http://www.oldgmctrucks.com/ go to “Discussion Boards”, “Technical Stuff”, then scroll down to my post, near the bottom of the first page, titled “Can anyone ID this Brownie………” posted by 51 1-ton 302.

Or you might try to right click on the link I posted above when I started this topic, select "copy shortcut" and then paste it into your address bar with "CTRL V". If this doesn't work and you would like to see the picture, please send me a private email and I will return a private email with the picture attached.

I've got the 63 Chev trucck manual [which covers entire line] in front of me and it covers two aux trans-the Spicer 5831 three speed and the 6041 four speed. The best way to identify either of these seems to be by the number of PTO shafts and by the size & type of the brake mechanism on the rear.

The 3 speed has 2 PTO's, a 10 1/2" X 3" band brake, takes 4 pints of lube and has ratio's listed as:2.00:1 puller gear, 1.27:1 underdrive, and direct drive.

The things that stand out in my memory from the two weeks [out of six] that I drove a twin-stick while I was a student at the Calif Trucking Assoc Driver School in 1976 were that the correct way to drive was the exact opposite of what you would expect: you would start by putting the main box in either 1 or 2 depending on grade and load, put Aux in under-under, then under, direct, then over--the next shift up used both sticks and was to first shift the aux back to under-under and the main to 2 or 3 [as above] and do both quickly enough so that neither of the internal gear trains slowed down to the point where the mesh was no longer possible. The other thing that added to the joy of driving this setup was that the stick for Aux was far enough to the rear that it was aukward for both sholder and elbow joints--AND the last thing that made this such a joy was that the shift pattern was NOT the fimilar "H" but instead was a pattern with u-u in the left front, u in left back, direct required going back to the neutral slot then to the right and then to right-rear with the shift to over being straight forward to right front[are we having fun yet?] It was critical that when shifting either up or down between under and direct that the stick go all the way to the neutral slot, then squarely to the other side and squarely into its final position. If there was even a slight error in this shift the result was that the aux box would then be in TWO GEARS AT THE SAME TIME!! I will never forget the one time it happened to me: on the Long Beach Expressway during evening Rush Hour-having to climb out of the Tractor with a large hammer-releasing the locks and jacking the cab up-climbing up on the left rear fuel tank and reaching way over with the hammer and pounding both sets of links into their neutral positions. After that came all the same in reverse order, restarting the engine, etc.

If the 3 speed is what you have, it's 14 pages including special tools and specs, which is about the max I could scan and send over a dialup connection without risking my ISP or yours getting POed. Let me know if you need it.

Cathouse

Thanks so much for the Brownie information. I think though that my unit is probably not a Dana/Spicer 5000 or 6000 series. The missing tag was in a different spot than 5831's I've seen, it has no brake, and it is flat topped (I read somewhere that the Dana/Spicers were round topped. I also don't think it could be a 6000 series because the one unit I've seen is much bigger. I've been told that the size increases with the series, i.e. 5000 is smaller than 6000 series. I'd bet it's even smaller than a SM420. You mentioned PTO shafts. I'm wondering if you meant to say PTO cover plates; spots where you would bolt on a PTO. My unit has two; one on each side.

My mount holes are different than on the 5831 on the GMC6066 site. Where the 5831 crossmember is sort of a banjo type vertical plate, mine would have to be a horizontal plate with 4 holes about 9" apart in a square pattern.

My biggest concern now is the ratios. If it's just 1.26:1 under I'm not sure that it will be low enough for me. I guess I need to mount it and the shifter and linkage to a frame of some sort so I can check the shift pattern and ratios. It's too difficult to push and pull the shift rods without the leverage of a shifter, with the thing rolling around on the floor.

Just a quick dual box story. 30 years ago when I was young and stupider I drove a big water truck for a drilling company. Twice I nearly killed myself because it had marginal brakes and I couldn't find a gear when I needed it. Worst was when I rolled out of control backwards off of a steep curvy muddy hill because it powered out just at the top of the hill. Neither box had syncros so I couldn't find a lower gear or even stick it back in the gear it had been in. Luckily the rear tires tobogganed around the curve thanks to the muddy uphill berm, instead of climbing the berm and flipping the truck.

Thanks again

Sidehill