A buddy just bought a 90 F-600, and I'm trying to find some info for him...
Vin 1FDNF60H1LVA42xxx
Trans code CB
Axle code G7M

Trans looks like an Eaton 5-speed.

I've never run a 2-speed axle: how are they supposed to be used?
Do you just select high or low range like a transfer case, or can you shift it on the fly and use it to split gears?

Do 2-speeds have planetary gear sets in them?

Thanks much!

Phy

 

Two speeds have a planetary set up in the rear axle housing. You can see the exploded view and get an idea of how it works here:

http://www2.dana.com/pdf/AXSM-0040.pdf

As for driving, they can be used to split gears and will shift on the fly.

HOWEVER, there are some limitations, and they have to be shifted correctly. They are upshifted without the clutch. Pull up, wait a half second, lift the throttle, feel the shift, back on the gas.

Downshifted UNDER LOAD by pushing down the button, stay on the gas, stab the clutch in/out quickly. YOU CAN NOT downshift the rear axle without a load such as a hill or beginning to accelerate.

Split shifting is possible, but you need to get the hang of the truck/trans etc first, plus you need to figure out if 4th hi is taller than 5th lo. A very bad surprise awaits you if you split shift from 4th hi to 5th lo and it's geared that way....

The big bang and the back end hopping off the ground will make you think twice about goofing off with a 2 speed axle. If you're lucky, it won't break the first time that happens. (I'm pretty lucky....)
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YOU MUST NOT TRY TO DOWNSHIFT THE REAR AXLE WHILE GOING DOWN HILL. I say "try" because that's all you'll be doing.

This video and part two will explain it in painful detail:

Eaton 2 Speed Axle Part 01 - YouTube

Actually, both videos are here:

https://www.ford-trucks.com/forums/1...barn-find.html

Later model two speeds MAY be more forgiving than older units, but don't bet on it.

 

Thanks 85, I just got done watching that video, & the part 2 video. That helps a lot!

 

1FD = FoMoCo USA Incomplete Vehicle.

N = Class 6, 19,501-26,000 lb. Gross Vehicle Weight Rating.

F60 = F600 2WD (gas).

H = 370 2V

1 = Check digit, FoMoCo use only.

L = 1990.

V = Kentucky Truck Assembly Plant.

A42XXX = 1990 Numerical Sequence of Assembly.

CB = Eaton model FS-3005-B 5 Speed Direct.

G7M: G7 = Rockwell model RS-15-210 Two Speed Rear Axle / 6.14/8.57-1 / 15,000 lb. Rear Axle Capacity // M = Ford 7,000 lb. Capacity Front Axle w/Power Steering.

 

Thanks NumberDummy, I really appreciate it!

 

We came across a great website for vehicle ID info. the link is:
www.mercurypickup.com/1968_ford_serial.htm

there is an underscore before and after the word ford. I know yours is a different year, but I'm guessing they will offer that info as well.