Hey GMCTD!

[Cowracer]

I just scoped out the pics on your 6X6. I like it!

What can you tell me about the Spicer 5831 Aux Transmission. Did you install it yourself? If so, What was involved? Can you shift on the fly? I saw an automatic shift lever, do you have a 700r4 or the 4L80e tranny? What did the setup cost?

I'd love tp have a Gear Vendors, but I thing $2500 is pretty high for an aux transmission.

Tim

[gmctd]

Thanks - that's a looker you're standing next to, also!

Better go get some coffee, 'cause I do like to jaw! ;)

Almost installed a 4L80E - I designed manual control\manual TCC lockup circuitry, no PCM.
Even designed and machined a 4130 0.750" steel adaptor for the NP205 xfer case.
But, I knew the OD was right behind the torque convertor, and didn't like the trans grinding along at 4.11 rpms in OD.
Not to mention reworking all the driveshafts, then doing them again if I didn't like it.

The 400 turbo is simple, durable. I can pull one, rebuild it, install it in a day, if necessary.

Had Cummins\Dodge internals (all made by the same company) installed in my GM D4 torque convertor for enhanced lockup. Gotta put it in nuetral to keep it from overheating, but it hooks up like a TCC. Decel is another matter, however.

So, the 5831 looked like a very good choice, since I already had one, and had installed another in my brother's F450 back in '90.

It is the size of an SM-465, shifting externally thru two sliders, mount the shifter anywhere.

Built in several versions, mine is 2.0:1 low, 1:1, and 0.73:1 od, with a nuetral position.

Designed for 1.5 to 2.5 ton trucks back in the '50s, input\output shafts are around 1.5"dia, and the unit is virtually indestructable.
Build date on mine is Nov-57.
Current availability unknown.

The front mount is the rear driveshaft support off my 3500, relocated and modified to accept the Spicer 1" bolts and rubber isolator pads.
Rear mount is '80s NP208(?)etc xfer case support, using those rubber isolators\bolts in fabricated brackets.
Brackets were white epoxied for contrast, but water rusted the bracket behind the paint, which conveniently flaked off just in time for the photo shoot! Epoxy does that, you know.

It shifts much better on-the-fly with a manual trans setup, but can be shifted smoothly by anyone with third degree black belt hand-eye-foot coordination, and a tachometer.

I leave mine in OD, :rolleyes: and I do have an external two-position VSSB decoder switch set up for OD=2.99:1\Direct=4.11:1 to be mounted on the shift lever (after I have it chromed).

So, I'm done typin', and I guess you're outta coffee......

[ 12-10-2003, 03:56 AM: Message edited by: gmctd ]

[Cowracer]

Coffee gone. Caffine shakes almost over...

There are spicers available on the internet at a few different locations. Prices unknown, but I would assume $500 would be a starting point. My truck is 2wd, so I would have to make all kinds of brackets and adaptors. I was thinking about having/finding a yoke that would fit the spicer input shaft, and using a common u-joint or even a short drive shaft to couple the spicer to the back of the 4l80e. There appears to be plenty of room in the truck for that.

I like the idea of dual VSB's to keep the speedo honest. Nice touch. I have a couple of 12 volt linear actuators laying around, so I would probably hook it up to shift with a toggle switch. Too bad I dont have the manual tranny, I could use the big red 2-speed rearend button to shift it, and really make people wonder. Oh well...

Nicely done all around on the truck..

Tim

[gmctd]

I machined and welded the yokes required to mate to the GM 3500 u-joints. They may be still available somewhere, would just take intense searching.
Bearings and seals are standard sizes, and are available.
The larger versions for 3 to 5-ton and 18-wheelers have electric or air shifters as standard.

If your truck has a two-piece driveshaft, install the "Brown-Lite" at the bearing hanger location - requires shortening the front and rear shafts.

The VSSB code is only two bits difference between 2.99 and 4.11 - takes a SPDT switch and three wires to accomplish.
Corrects the speedo, but also is PCM's clue to fuel management based on vehicle speed vs engine rpm, as well as cruise.

Good luck with your project.

[ 12-09-2003, 06:33 AM: Message edited by: gmctd ]