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I just picked up a 3 speed brownie, its a model 6231... I did a search here and found one thread but no mention of ratios... I did find this when I was searching the internet:

http://www.oldmacksrus.com/trannys.htm

If you scroll down a bit it lists a 6231A and a 6231D. Mine has no letter however, and the tag isn't beat up or anything, so I'm confident it hasn't been worn off or something..

Anyone have any chart that shows what the ratios might be? I can count input vs. output revolutions but I'm going to need a 2 other friends to come over to help me get it out of the trunk of my car first!

Also would be interested in torque rating.. I think its gonna be up there.. This thing makes my Watson look like a tinker toy..

Any help is appreciated.

Jason
 

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Mystery solved.. I ended up getting in touch with a guy through ebay through a listing I have going for another aux trans.. He was very helpful and has obviously been around old driveline stuff a LONG time... He had the literature for it and was nice enough to send me this:

Model 6231 Helical Gear 3 Speed Auxiliary/ Three speeds forward - no reverse - used in conjunction with standard four or five speed transmissions. Assembly 001981 Per March 1947 Production stopped in esrly 1957. 375 pound feet net torque (Nominal rating 320 ft/lbs in another listing) (similiar to Brown -Lipe 6041) .Average Net weight 370 pounds Oil capacity 8 pints. Was around as early as 1938 as the single size 6031.

6231 2.14 1 .69
6231A 1.24 1 .86
6231B 2.14 1 .86
6231C 1.24 1 .60
6231D 2.14 1 .74
6231E 1.24 1 .74
6231F 1.5 1 .86


Hope this is helpful for someone down the road when they search!

Jason
 

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I was always told that the first number(6) in your case is the torque capacity that is for the engine(600 ft. Lbs) in your case. Application and lack of broken Brownie's seem to bear this out.
 

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Yes, I've read some original literature that supports Ed's thoughts. First digit of the model X 100 ftlb is the max allowed engine torque.
I've always thought this a strange way of rating an auxiliary transmission because it does not take into account the low gear ratio on the main transmission, which for example could develop 7 X engine torque. My best guess is they had in mind the max likely gear reduction of any main transmission and built and rated the auxiliary accordingly.
 

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actually it does account for torque multiplication of the trans.

600ftlb engine x 10:1 first gear is 6000ftlbs
600ftlb engine x 7:1 first gear is 4200ftlbs.


if you had a hot 5.9 making 1200ft and had a 20:1 18sp eaton, well you can guess whats gona happen.
 

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You're saying it's 6 X 1,000 ftlb as the rated input torque of the auxiliary; 6,000 ftlb?
Not referring to the engine torque directly as Ed and I thought.
 

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What 2 tons told me is the same as a real old timer in town that has over 100 old trucks told me. He also has old hit & miss engines & over 40 steel wheeled JDs. Unfortunately, he passed this summer after setting up for Western Days, here in Kanab, UT.

Ed
 

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I looked through all the Spicer info I have and here is what I can find on ratings of auxiliary transmissions, as applied to 8,000 series.


Note this is a revision from their previous ratings whatever those were.
So now the 8,000 series auxiliary is rated for total input torque of 4,400# ft. or 6,650# ft. depending on model/ratio. Defined as main transmission first gear ratio multiplied my maximum engine torque.
These numbers do not work out as 8 from the model number multiplied by 1000 or even 100. More like 8 X 550 or 800

Also note that the 8,000 series auxiliary as sold in a married compound transmission is rated by maximum engine torque from 675-1,020# ft. depending on model.
This method resembles and most of the ratings fall close to 8 from the model number multiplied by 100 and applied as max engine torque. These may have been even closer before this revision.

It'd be nice to find some sales literature..
However going by this evidence alone I think it's reasonably safe to say that the original intent of the model number was to denote the nominal allowed max engine torque (for the auxiliary transmission) as 100 X the first digit of the transmission model number; or an 8,000 series auxiliary is rated for 800# ft. max engine torque.

If looking for the actual max allowable input torque for the auxiliary that is not given by decoding the model number.

That said I'd be glad to learn more about this, anyone else have some old Spicer literature?
 

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i was looking at some of my books while i was typing before, and at least in the 1;5 binders it didnt have what i posted, so idk wtf i got that from.


i have 5 years/revisions of all spicer transmission and aux trans from mid 60's - late 80's. 4-20 speed trans, x+x trans, brownie boxes, shifter mechanism's and pto's. full explodes, cut away diagrams, parts list with ##[fat lot a good they do]

one page dated 1969 seems to be the only one listing power inputs.

regarding straight trans, compound trans , and aux trans.

"first two digits..... capacity of the unit
third digit ..... # of gears
fourth digit.....case material, 1=iron, 5=alum. "

" 8-3-4-1-a
725-950ftlbs [approx engine torque]
3 speed
iron case
first set of ratio's, 2.40, 1.29, 1.00, .84"
 

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Yea, I've got two huge binders full, sounds like we have a lot of the same stuff, parts list, service manuals... but what we need for this question is sales literature and application info.
 

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Additionally, there are 5831, and 5531, both pick-up sized; the 5531 is physically smaller than the 5831, both probably marginal with a 6BT, but OK for less torque, or gentle driving. Always shift out of OD first when load increases-direct is stronger since not using the cluster.
 
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