Hey guys I have a 1946 Ford with the Eaton 2-speed rear end. The 2 speed shifts fine from low to high in all gears and speeds, but will not shift to low range unless I'm going pretty slow, basically 2nd gear. I can hear it trying to shift but will not go into low range.

What do you guys think? Maybe the shifter on the rear end? It is a vacuum shifter by the way.

Thanks,

Travis

 

Mine does the same thing.. When you go to low it will grind, try tapping the accelerator to speed up the drivetrain and it should fall into place..Jmo

 

Did you check the spring in you shift can.Think I remember correctly some spring action pushes it to low and vaccuum pulls it to high

If it is gringing you are probly not getting it syncronized is is difficult for some folks

 

Thanks, guys I will give it a try this weekend, I just bought this truck and got it on the road. Never drove a 2-speed rear other than on the farm, in low gears, this is the first time I have been on the road with one.

Thanks,

Travis

 

We had several two speed axles--a couple of '48 Fords, '51 IH, '58 Ford F600. Just so you know I'm not pulling this out of thin air.

You CAN NOT downshift the old two speeds like a regular transmission.

You only downshift under load, or when splitting gears.

Under load:

--Stay on the gas

--Push the button down

--Stab the clutch as fast as you can. (in and out, no waiting)

This takes the load off the axle, which allows it to shift, and brings the revs up to match the new driveshaft speed, and is quick enough the actual driveshaft doesn't lose enough speed to goof up the shift.

To split gears, you push the button down when you get into the higher gear--2nd high to 3rd low, for example.

You can split on the downshift too, just pull up first, before you hit the clutch.

For straight upshifting, NO CLUTCH:

--Steady on the gas

--Pull the button up

--Off the throttle, feel the shift, back on the gas.

Watch this one starting at 8:27, unless you really want more info about the 2 speed:

YouTube - Eaton 2 Speed Axle Part 01

Part 2 picks right up.

YouTube - Eaton 2 Speed Axle Part 02

Part 2 continues on with tips etc.

One thing to remember--never shift it at all going down hill.

 

I disagree with that.
I cut my teeth on manual and vacuum two speed axles they can upshift,downshift or split at any time needed up hill or down.The electric and air shifts are a little easier

It's all in technique

 

Not the ones I drove.

I was in a much later (1970s) Chevy C60 that didn't seem to mind how you shifted it, so I don't doubt what you say.

So, as they say, ymmv with the two speed. When things go bad with a shift and the rear end jumps off the ground and it feels like a train hit you, you tend to be more conservative in how you shift it.

Watch the Eaton video, they are very specific about not shifting while going down hill.

 

I agree just because you can does not mean you should shift the rear down hill. If you miss the shift and the rear end is in neutral you loose all engine braking ability and are relying entirely on the brakes. but according to my owners manual and personal experience the important thing to remember when shifting a vacuum rear is to have your foot on the gas whenever operating the shifter pull ****

 

My hint is (when possible) to move the two speed **** a little early (with torque on drive train) for shift spring wind-up. Let the spring make the shift rather than the motor. Same would apply with vacuum. Extra time for vacuum increase (vacuum shift) or vacuum decrease (spring shift).
Did I get it right Ray?

 

Yes you always pre-select the axle range (with vacuum ,electric or air shift)
When shifting from low to high when you let off the throttle the axle will then shift smoothly
When down shifting the axle you let off the quickly reapply and the axle downshift will be smooth

Most vacuum shift chambers are spring loaded toward low,this is a saftey feature for parking and makes split shifting easier.
Once the vacuum leaks off the axle will stay in low range,where if left in high range and driveline pressure is relieved the axle could/will shift to neutral.therefore all parking should be done in low range.

This shift technique also works with Roadranger transmissions

 

thank you for the video! now I know i have a planetary in the rear. what fluid? temp ranges from a 100F to 15F?, also how do i know if i have soft fourth? meaning 4 low to 5 low?

 

90w gear oil for the axle.

No one knows what your trans is.

You can post your warranty plate info for a decode, but it will have to be figured out with the trans ratios and the axle ratios.

Some 5ers are OD, some are direct.

Feel free to start your own thread with all that info--throw in the VIN if you like, that always helps.

 

You beat me to the YOUTube vids, they are VERY technical. However it takes practice to master this drivetrain type. I've been driving for 14 years and it's close to a super 10, close but not close enough. I have a 75 f 750 with a 5 spd and a 2 spd rear. I'm still trying to figure it out. I wish you luck.

 

Most of the time, it's just easier to use the two speed as an extra gear.

My dad never split and I thought he was going to come unglued when I did it once....