Author Topic: Electric transfer case vacuum servo? (Read 9876 times)

rohnk · « **on:** June 21, 2011, 10:20:51 PM »

So I was thinking about replacing the vaccuum servo on the transfer case with an electric motor to switch between 2 and 4 wheel drive. The benefit to this would be better reliability than the vaccuum system. I know these work well when they work but vaccuum lines leak or break all the time. Just thought of the modification as an idea. Thoughts?

eaglefreek · « **Reply #1 on:** June 21, 2011, 10:42:00 PM »

It's been talked about in the past, but I don't recall anyone doing it. Do you have an idea of which servo you would use?

thereverendbill · « **Reply #2 on:** June 21, 2011, 10:57:44 PM »

there is a writeup in the eaglepedia of a cable operated unit

rollguy · « **Reply #3 on:** June 22, 2011, 12:54:28 AM »

Quote from: thereverendbill on June 21, 2011, 10:57:44 PM

there is a writeup in the eaglepedia of a cable operated unit

I think a cable would be the best.

rohnk · « **Reply #4 on:** June 22, 2011, 09:08:12 AM »

I read the article about the change to a cable and I like the idea but don't like that the handle sticks out of the floor between the seats.

My thought would be to try and keep the existing switch location and appearance but modify it to switch an electric solenoid. I have no idea what servo or solenoid to use as I haven't thought it through that far, but I was interested in the idea.

Maybe an electric solenoid from a garden tractor lift mechanism would work. It wouldn't need to be anything really heavy as the lever does not require a lot of force to switch between 2 or 4 wheel drive. A bracket would need to be fabricated of course, but all of that could be hidden under the skid plate.

twoslowinwyo · « **Reply #5 on:** June 22, 2011, 09:49:45 AM »

check these out, you might find what you need here. i have used this co. products in the past and they make good products. LAZ

http://www.solenoids.com/

rollguy · « **Reply #6 on:** June 22, 2011, 10:20:09 AM »

Quote from: rohnk on June 22, 2011, 09:08:12 AM

I read the article about the change to a cable and I like the idea but don't like that the handle sticks out of the floor between the seats.

My thought would be to try and keep the existing switch location and appearance but modify it to switch an electric solenoid. I have no idea what servo or solenoid to use as I haven't thought it through that far, but I was interested in the idea.

Maybe an electric solenoid from a garden tractor lift mechanism would work. It wouldn't need to be anything really heavy as the lever does not require a lot of force to switch between 2 or 4 wheel drive. A bracket would need to be fabricated of course, but all of that could be hidden under the skid plate.

Some (or most) garden tractors have a linear actuator (12v) for raising and lowering the deck. The problem with something like this, is that force they exert will break something if the gears don't quite line up. If there is some type of solenoid that has enough power to shift the gears, but not enough to FORCE them into meshing (thereby breaking something), that would be good. It would also need to be slow actuating. Something fast like a starter solenoid would surely break something. That is why they engineered the shift mechanism with vacuum in the Eagle. Vacuum will put a small amount of pressure until the gears mesh. Most of the later 4X4 shift mechanisms are electric actuated, so you may want to look into how they operate.

rohnk · « **Reply #7 on:** June 22, 2011, 11:54:45 AM »

My dad took a convertible top motor from a T-bird and mounted it on his John Deere 110 to raise and lower the snowblower and mower deck. The way he has it wired it that it only moves when he is holding the momentary switch that gives it power. This gives him infinite places to stop throughout the motion of travel on the motor. I know, WAY to much torque for this application, but a simple idea.

My thought is that is the length of travel on the shifting arm is _{(for the sake of discussion)} 1/2", then I would use a slow moving solenoid powered from 12V with a degree of travel of 3/8". This means that if the gears were not meshed when activated, it would simply stop at it full length of travel _{(or as far as it could travel)} and hold pressure until the vehicle rolled a little bit for everything to "click" in. You could control the amount of pressure by moving the solenoid forward or backward slightly to increase or decrease pressure.

At least this is my simplistic view of the idea!

GRONK · « **Reply #8 on:** June 22, 2011, 11:57:08 AM »

What about something as simple as a 12V idle solenoid form a Motorcraft. Positive engaugement, short throw, inexpensive. I have about 500 of them if you want to try. Pay shipping and I'll send you a few.

rohnk · « **Reply #9 on:** June 22, 2011, 12:19:27 PM »

Thanks for the offer Gronk! It is a good idea to try those. I'd have to use one for the front axle and one for the transfer case. The throw on the front axle is 0.64" if I remember right from the Eaglepedia. I don't know how long the throw is on the transfer case. How much movement do those solenoids have?

GRONK · « **Reply #10 on:** June 22, 2011, 01:11:50 PM »

Probaby a little over 1/2" I'll dig some out. I believe some are sdjustible too. I have used these for all sorts of things in the past. VERY simple to work with.

jim · « **Reply #11 on:** June 22, 2011, 01:17:00 PM »

Quote from: rohnk on June 22, 2011, 12:19:27 PM

Thanks for the offer Gronk! It is a good idea to try those. I'd have to use one for the front axle and one for the transfer case. The throw on the front axle is 0.64" if I remember right from the Eaglepedia. I don't know how long the throw is on the transfer case. How much movement do those solenoids have?

To simplify it you could lock in the front axle and eliminate one complete set up.

rohnk · « **Reply #12 on:** June 22, 2011, 03:56:03 PM »

Nice idea to lock the front axle. I didn't think of that! What is a safe way of locking it that is reversible in case it doesn't work out? I'd hate to weld the thing together and mess soemthing else up!

rollguy · « **Reply #13 on:** June 22, 2011, 04:45:14 PM »

Quote from: rohnk on June 22, 2011, 03:56:03 PM

Nice idea to lock the front axle. I didn't think of that! What is a safe way of locking it that is reversible in case it doesn't work out? I'd hate to weld the thing together and mess soemthing else up!

Hose clamp around the shaft of the shift fork.

mudkicker715 · « **Reply #14 on:** June 22, 2011, 04:51:07 PM »

Quote from: rohnk on June 22, 2011, 03:56:03 PM

Nice idea to lock the front axle. I didn't think of that! What is a safe way of locking it that is reversible in case it doesn't work out? I'd hate to weld the thing together and mess soemthing else up!

Its in the eaglepedia

rohnk · « **Reply #15 on:** June 22, 2011, 08:05:25 PM »

Thanks, I'll check it out.

GRONK · « **Reply #16 on:** June 22, 2011, 08:09:26 PM »

The only prob I see w/ locking the front axle is you will always be pushing it. I did that w/ a GWag once and regretted it. It did work though, but turning sucked even in 2wd.

I can use a flat rate box (USPS) for shipping if you want some. What ever that comes to

[email protected]

No worries if you have a better plan, was just a thought that popped in the noggin

Mechanic · « **Reply #17 on:** June 22, 2011, 09:41:45 PM »

I did a little looking into thtis myself when i was farting around with the vacuum system on my 84. Fed up with not enough vacuum and weak pots and such.

I haven't tried it yet, but I'm think door lock actuators might be the ticket. They are strong enough to engage the transfer case while being slow enough not to break anything.

mudkicker715 · « **Reply #18 on:** June 22, 2011, 10:07:33 PM »

Quote from: GRONK on June 22, 2011, 08:09:26 PM

The only prob I see w/ locking the front axle is you will always be pushing it. I did that w/ a GWag once and regretted it. It did work though, but turning sucked even in 2wd.

I can use a flat rate box (USPS) for shipping if you want some. What ever that comes to

[email protected]

No worries if you have a better plan, was just a thought that popped in the noggin

My 84 was locked up in the front axle since I got it almost 10yrs ago. It drives like/as it should.

Mechanic · « **Reply #19 on:** June 23, 2011, 01:28:01 AM »

Quote from: GRONK on June 22, 2011, 08:09:26 PM

The only prob I see w/ locking the front axle is you will always be pushing it. I did that w/ a GWag once and regretted it. It did work though, but turning sucked even in 2wd.

I can use a flat rate box (USPS) for shipping if you want some. What ever that comes to

[email protected]

No worries if you have a better plan, was just a thought that popped in the noggin

It should make no diference to the handling of the car. Eagles even come stock with the front diff locked in. 80's and some early 81's were full time 4X4 and it was only from 81 to 84 or 85 that you could get an eagle with an unlocking front diff. Everything beyond 84/85 has a locked in diff and it dosen't effect the handling or turning of the car.

The gwag you used must of had some sort of LSD on the front for it to be difficult to turn.

rohnk · « **Reply #20 on:** June 23, 2011, 09:45:05 AM »

Thanks again GRONK. I'll send a few dollars your way!

Door lock actuators are another good idea. I wonder about them being sealed though. I might get one of those from a junker to try out.

Lots of ideas, now all I need is the time!