Figure 1 Shift Diagram ~~~ Figure 4 Spicer 5831-B
This Page Covers the Spicer 3-speed auxiliary transmission Model 5831-B which was used
as optional equipment in GMC 5000 series & bigger trucks. The Transmission is manually
shifted & has 3 forward speeds, Low, Direct, & Overdrive. See Figure 1 for shift diagram.
Gear shifting is accomplished by use of a shift lever in the cab of the vehicle, which is
interconnected to the auxiliary transmission with rods or cable assemblies, depending on
Vehicle. The Auxiliary transmission in mounted to the rear of the main transmission on a
bracket attached to the frame side rails & crossmember. Hand brakes & speedometer drive
are assembled at the rear of the auxiliary transmission.
These are sometimes called a "Brownie Transmission".
You will be needing the following parts from the donor truck to install this auxiliary transmission
into a truck that did not come equipped with one. Pictured parts are from the auxiliary transmission
setup I got from a 1965 GMC W5500 dump truck & may be different from what you find.
You will of course need the auxiliary transmission, shift tower, shift linkage, mounting bracket,
both drive lines, & the transmission output flange from the main transmission. You will also need
the park brake setup if you don't already have a parking brake in the rear axle.
There should be a Serial & Model tag on the right side of the auxiliary transmission, if it is
there you will have the model number, the Spicer 5831 auxiliary transmission came in 8 different
models, you may find a letter following the 5831 on the tag, this is what tells these apart, &
from what I have seen so far, the difference is in the over-drive or under-drive. Letters used
are A thru G. The Spicer 5831 has the gearing options (Ratios) shown below.
Spicer 5831 Auxiliary Transmission Data
Length 18-13/23"
Torque 275 lbs. ft.
Horsepower 150
PTO 6 bolt-R/L
U-joint series 1410-1650
|
Manufacturer |
Transmission |
Under-Drive |
Under-Drive |
Direct |
Over-Drive |
Oil Capacity |
|
Spicer |
5831 |
|
2.00:1 |
1.00:1 |
0.73:1 |
4 pints |
|
Spicer |
5831 A |
|
1.54:1 |
1.00:1 |
0.73:1 |
4 pints |
|
Spicer |
5831 B |
|
2.35:1 |
1.00:1 |
0.85:1 |
4 pints |
|
Spicer |
5831 C |
|
1.27:1 |
1.00:1 |
0.85:1 |
4 pints |
|
Spicer |
5831 D |
|
2.00:1 |
1.00:1 |
0.85:1 |
4 pints |
|
Spicer |
5831 E |
|
1.27:1 |
1.00:1 |
0.73:1 |
4 pints |
|
Spicer |
5831 F |
2.00:1 |
1.27:1 |
1.00:1 |
|
4 pints |
|
Spicer |
5831 G |
2.00:1 |
1.31:1 |
1.00:1 |
|
4 pints |
The Spicer 5831-B is the one used by GMC, I found some of the information here in the GMC
Maintenance Manuals. I did a search the web for
Spicer 5831
& found more info. Then I
Recived in the mail a copy of a Spicer Auxiliary Transmission brochure with all the Correct
info now found in the chart above. The Spicer 5831-F was used by Chevrolet in 1960. Both the
5831-E & 5831-G model do not have an overdrive. The 5831-D was used in Ford Trucks.
A side-by-side compairision of the Spicer 5831-B & the SM-420 4-speed.
For more on Other Transmissions used by GMC see the Transmission Data Page.
Also see the Gear Charts page for some ratio tables.
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© 2000-2006 6066 GMC Trucks. Last Updated January 26, 2006.
