I don't have any info as far as torque rating, but ratios are easy to figure out. Mark the input and output shafts, turn the input and keep track of the number of revolutions, until the output has made 1 turn. That is your ratio in that gear. Do this for each of your gears (3) and you will know all the ratios.

 

I have a copy of the original sales literature for your transmission. It is too big to post here so if you IM me and send your email address I will send you what I have. Your trans has 1.49-1, 1-1, .75-1 ratios. (75 percent overdrive) Chic

 

I have the same thing but different serial # 04907 same model number could you send me info plz felipegranados @ att.net

thank you,
SGT/USMC

 

.75:1 is 25% overdriven. Nice find!!!

 

Awesome! 25% should be great for what I'm trying to do. Picked it up for $275. No shifter, but that shouldn't be to hard. Chic, I'll Message you my email, I appreciate it!


Jason

 

awesome score!!!!!!!!!

 

Chic,
Got your email, do you have any idea what years they were produced? Also interested to know what type of oil it requires..

Thanks
Jason

 

50 weight, just like my 5831B most likely.

 

Gear oil or motor oil?

 

my manual shows SAE 50 engine oil of good quality.

 

That would be my best guess as well

 

Nice Find!

 

Jason, I have the complete manual for these transmissions......Pm me your snail mail adress and I will [ut it on a cd for you. It has exploded views and disassembly/assembly instructions. Chic also I have a couple of model 43's if anybody is lookin for one!

 

Chic , I know this is an older post, I’d like to get my hands on any of those manuals you may possess/ Ltiran56@me.com . Let me know what you may need for copies . Thx .

 

That would be great.. I'll pm you my address.

Thanks!

Jason

 

Best known strength puts Watson OD's weaker than Brownies, so if one has a 6BT, use care. Brownies are rated on ENGINE torque, i. e. 5531 can handle a 550 lb. ft. torque engine.

 

Howdy Ed , ever get you 471 gmc COE gathered up and relocated to the Mack Truck Farm?

 

ed is there a place i can find these ratings somewhere?

 

Ok I took it partially apart, to flush out the crud at the bottom of the case (no chunks thankfully) and give it a check over. Upon inspection, the OD gear on the countershaft has some play, it can walk forward and back on the shaft about 1/8". Wayne was nice enough to send me some info on the box, but it doesn't list any gear backlash or axial play limits/settings etc... Is this how its supposed to be? There doesn't appear to be any funny wear on the teeth of that gear or its mate on the main shaft. Just don't want to stick it in to find out something is wrong.

Thanks
Jason

 

Thanks for the info Ed, this is going behind a 453T in a single cab GMC pickup. I don't think I'll be putting more through it than it can handle. Was just curious to know though.

Jason

 

Don't know where I heard that, Dan maybe?

 

Your overdrive will be 1 divided by .75 which is the inverse ratio ( if you remember you algebra ) so the overdrive is 1 to 1.33 or 33% not 25%. Most people calculate it the wrong way and end up with smaller than actual overdrive. You can verify this by turning and counting the shafts.

 

Do you multiply rpms by 25% or 33%?

 

That's funny as I was messing with it last night I thought it turned a good 1-1/3rd turns to 1 revolution of the imput. Hey a little more OD will be helpful for some better mileage, so good news there!

Anyone have any idea if that OD gear should have play like that? I've never had another one of these boxes apart to know how they should be.

Jason

 

Scored on a Watson 45 and the shifter, couldnt pass on the price. Small size but heavy duty. Underdrive/ 1:1 and an OD.

 

With those ratios , you can use it as a 3 way splitter, like the Eaton 3 speed axle on a tandem .

 

Hi Dan. Actually read information on some of your old threads on ATHS and justoldtrucks to find out exactly what ratios I had. Behind a Getrag/3.54r+p with 30" tires puts me in the sweet spot. Found a 59 Ford crewcab if the guy will loosen his grip some. In case he does, I located a fleetside shortbed to replace dump bed on it.

 

Red, do you know what the gear ratios are in that box? Sure looks more compact than some of the 5000 series Spicers boxes.

 

Wayne nailed the ratios. It is definately smaller than Spicer/Brown Lipe boxes, maybe a little shorter than a NP435 but I think there is plenty of strength, gears are wide as NP203 gears.

 

The ratios in that box are 1.49/direct/.75

redbronco.... sell me that.

 

That is a sweet little package!