2 quick questions RE '40 COE with Eaton 2-spd axle.

• Which rear wheel side is the drive wheel?

• Would it be theoretically possible to have the entire rear axle in the air (tires off the ground), turn the driveshaft by hand and NOT have either rear wheel turn as a result?

 

Only if the axle is in neutral. Usually with both wheels off the ground, turn the driveshaft and both wheels will turn. Power would be distributed to each wheel equally as long as the traction is equal. As traction changes, either side can spin.
Mark

 

So the Eaton's are 'limited slip' rears?
I was not aware one could have the 2-spd 'between gears'...

 

Maybe the 2-speed axle is between the High and Low ranges. Like not quite in High and not quite in Low. Can you operate the shift linkage by hand and feel it go into H or L range? Turning the drive shaft should turn the wheels.

 

There is no actual neutral position on the shift lever type 2 speed like there is in a transmission, but the lever could be between gears if not shifted all the way into high or low. The Eaton axles are not limited slip, any axle will pull equally with both wheels until one looses traction. There is no "drive" wheel on a vehicle, either one or both will pull depending on the conditions.
Mark

 

I just got my last drum turned, so I have to re-assemble that (driver's) side.

Do you have to shift the rear while in motion?
Right now (immobile), the lever won't move. Here's the position it's in :

 

i got to ask! i see your 2 speed is not vaccum operated. do you have a lever in the cab to work the high to low . i can,t visualize how the lever goes from the front to the rear differential. someone already post for me a picture and it was a cable between frame and differencial. a cable will pull, but wouldn,t you need some sort of spring to get back. i want to install my 2 speed with a lever as it was originally. my truck had a lever but nothing hookup to it,at some point the rear end was changed with a vaccum style 2 speed. so my queation is ,do you have anymore pictures of your setup.

 

Can you disconnect the cable from the shift arm on the differential? The arm should move fairly easily but you may have to turn a wheel or driveshaft to get it fully in gear.

 

I have the vacuum style shift, but after a story I heard I would rather have it manual. From what I gather the vacuum shift has a spring holding it normally in the 'standard ' position. When the vacuum canister valve is accuated at the dash board the vacuum over rides the spring tension and engages the other position. These is a space or interval where neither gear is engaged and the driveshaft will free spool with no connection to the rear wheels whatsoever. Now consider that the parking brake is attached to the front of the driveshaft. The dash board instruction plate states that it's necessary to have the **** pushed in before parking the truck. So, you park on a hill (that's all we have around here), set the hand brake, put the truck in gear but forget about that **** or maybe just want to start back out in that range when you leave. Either way, it's left in the out position. You go into the Hillside Cafe, or perhaps the 'Water's Edge Diner' for coffee. While you're in there sipping and visiting, the vacuum is slowly leaking off and the spring is starting to do it's thing. As the lever creeps through it's slow arc, it eventually finds that neutral place where the driveshaft , which is doing ALL the work of holding the truck back, no longer has any authority over the rear wheels........ There were 3 old bachelor farmer/logger brothers who lived about a mile down the road from me, but when I moved here in the '70s there were only two, because as they told me, brother Dick had been killed when his loaded dump truck lost vacuum to the 2 speed axle and rolled over him and then down a steep hillside at the quarry sometime in the early 1960s. Makes me want to put a key operated buzzer like we have today when we leave the keys in or the headlights on. Do they make them for 6 volts? Anyway, that's today's safety lesson from Gramps.

 

UPDATE :
I tried to disconnect the cable from the arm on the rear: disconnected both the U-bolt and the bracket that holds the cable on the differential, but the space between the shift arm and the housing is too tight to drop the cable end out. Got everything all loose, greased the cable fittings.

Then took the cover off below the shift arm. Interesting- those 2 vertical raised ridges on that cover are detents, and as the shift arm moves, a spring-loaded pin rests in either detent. Since those 2 vertical ridges are only about 3/4-in apart, that's how far the shift arm moves to change ratios.
Cleaned it all out, cleaned the pin & spring, greased everything, reinstalled. Shift arm works well, could hear things clunking inside the rear, made sure it was in the 5.83 detent. It would be nearly impossible to get the detent pin 'in between' IMO.

You can see the 2 vertical ridges at 9 o'clock to the shift arm.

Turned the driveshaft with the *** of the truck up. Right now I only have the pass side tires on; the driver side is completely disassembled. Driveshaft turned, pass tires did NOT. Slipped the axle temporarily into the housing on the driver's side, engaged the splines, turned the driveshaft and the driver's axle turned.

Not sure if it was the fact that one side had the weight of a drum & dually on it that was making only the driver's side turn, but I assume so if the 'both wheels turn under equal traction' contention is true.

Besides the fact that the rear shift linkage under the cab seems all sorts of loose & wobbly (I'll look at that down the road), everything seems good pending the test drive. On to other components...