AMC Eagle Den Forum

The Shop => 4X4 and Driveline => Topic started by: Softbuster on July 15, 2012, 06:25:32 PM

Title: Vacuum shift actuator replacement?
Post by: Softbuster on July 15, 2012, 06:25:32 PM
Well the Vacuum shift actuator thing on my eagles transferr case does not shift anymore.  I did convert it to shift on the fly (using a hose clamp and removing the vacuum lines on the front axle).
It worked great for a while but now the actuator at the t-case is just stuck, I took it off and it is just not moving anywhere.   

SO... my question is, can I remove the actuator at the front axle and use it at the t-case and use something else to keep the front axle engaged?

I found THIS on summit racing website for jeeps to keep a dana 30 locked in all the time.  SHOULD work just fine for an eagle.   http://www.summitracing.com/parts/POS-1100/?rtype=10

Unless someone knows where to get a new actuator?? or has one I can buy?????
Title: Re: Vacuum shift actuator replacement?
Post by: midtownboarder on July 16, 2012, 12:39:31 PM
not sure if this would apply in your case, but would this work to keep in engaged all the time?

http://emeraldgreen97.wordpress.com/2011/03/08/renix-era-dana-30-vacuum-disconnect-mod/ (http://emeraldgreen97.wordpress.com/2011/03/08/renix-era-dana-30-vacuum-disconnect-mod/)
Title: Re: Vacuum shift actuator replacement?
Post by: Jurjen on July 16, 2012, 01:31:06 PM
You can buy the actuator for Shift on the Fly here:
http://www.teamgrandwagoneer.com/cgi-bin/partsSQL/search.cgi?query=vacuum&catid=
Title: Re: Vacuum shift actuator replacement?
Post by: Softbuster on July 16, 2012, 05:03:01 PM
You can buy the actuator for Shift on the Fly here:
http://www.teamgrandwagoneer.com/cgi-bin/partsSQL/search.cgi?query=vacuum&catid=


Yeah sorry thats not in my price range....
Title: Re: Vacuum shift actuator replacement?
Post by: Softbuster on July 16, 2012, 05:07:10 PM
the question I have is can i remove the actuator from the assembly and keep that retaining pin in place for the shift fork???  or is it all one piece?
Title: Re: Vacuum shift actuator replacement?
Post by: mudkicker715 on July 16, 2012, 05:10:53 PM
Yes it can stay ingaged all the time. i was waiting for someone else to answer you. i have done it i have another i shift to 4wd when needed by manually shifting it.
Title: Re: Vacuum shift actuator replacement?
Post by: Softbuster on July 16, 2012, 07:06:55 PM
I would like to get it to work properly so that I can sell the Car.
That Is why I would like to retain the shift ability of the transfer case via the original switch.

Can I somehow remove the vacuum actuator from the front axle assembly and use it on the transfer case???
Title: Re: Vacuum shift actuator replacement?
Post by: thereverendbill on July 16, 2012, 10:10:06 PM
tomarow I will be in the salvage yard I like to frequent ..... if you want me to i can get one off of one of the sedans there
Title: Re: Vacuum shift actuator replacement?
Post by: philotomy on July 17, 2012, 10:19:43 AM
yeah I just realized before my trans install (attempt) that mine had quit moving/froze up.Happy to see it's available but not at that price,guess I'll stick with manual shifting until I can track down a cheaper replacement.
Title: Re: Vacuum shift actuator replacement?
Post by: 85AmCfreak on July 17, 2012, 02:07:56 PM
You can buy the actuator for Shift on the Fly here:
http://www.teamgrandwagoneer.com/cgi-bin/partsSQL/search.cgi?query=vacuum&catid=

OMG I bought that exact part from that site about 4 or 5 years ago for 50 dollars talk about a mark up.
Title: Re: Vacuum shift actuator replacement?
Post by: txjeeptx on July 17, 2012, 03:14:01 PM
Your question: Can I somehow remove the vacuum actuator from the front axle assembly and use it on the transfer case???

The actuator on the front axle is different enough, mounting-wise and actuator-shaft-wise, to not be easily adapted to use it on the transfer case.

If any of your local salvage yards have any full-size Jeep Grand Wagoneers that were equipped with Selec-Trac, then they have a shift actuator that you could use.

The TeamGW price is obscene, but they are a specialty company, and can charge whatever they think they'll get from someone doing a perfection-restoration on a full size Jeep. The prices for FSJs in good shape are obscene, too, at least from the two FSJ-only dealers here in TX. Its a shame they have a role in the inflated prices of parts like the one you need.

The auction sites might have what you need, try searching for Grand Wagonner transfer case vacuum shifter. There are enough of them out there that someone is bound to be selling that part ,if you can't find it by searching for a listing specific to Eagle.
Title: Re: Vacuum shift actuator replacement?
Post by: Softbuster on July 17, 2012, 07:36:22 PM
Ok thanks for the Info.

I
tomarow I will be in the salvage yard I like to frequent ..... if you want me to i can get one off of one of the sedans there

so am I a day late for you to grab one for me???
Title: Re: Vacuum shift actuator replacement?
Post by: thereverendbill on July 17, 2012, 10:24:55 PM
Ok thanks for the Info.

I
tomarow I will be in the salvage yard I like to frequent ..... if you want me to i can get one off of one of the sedans there

so am I a day late for you to grab one for me???
I thought I'd have the cash to head over there today but as fate would have it I have to wait another day or 2 to head over ....... I'll grab as many as i can find
Title: Re: Vacuum shift actuator replacement?
Post by: 85AmCfreak on July 18, 2012, 05:46:52 AM
Is there a way to replace this vac motor with an electric motor?
Title: Re: Vacuum shift actuator replacement?
Post by: thereverendbill on July 18, 2012, 06:06:19 AM
Is there a way to replace this vac motor with an electric motor?
I have been thinking the same thing ..... i am leaning towards trying a GM power lock motor once I take possession of the  4 door sedan i am purchasing 
Title: Re: Vacuum shift actuator replacement?
Post by: txjeeptx on July 18, 2012, 11:14:00 AM
I was thinking exactly the same thing - a power door lock solenoid may be a decent replacement - easy to wire up, and reliable.
Title: Re: Vacuum shift actuator replacement?
Post by: carnuck on July 18, 2012, 12:43:55 PM
I have a used one in my for sale stuff
Title: Re: Vacuum shift actuator replacement?
Post by: captspillane on July 18, 2012, 09:02:06 PM
I doubt an electric solenoid will work. A car window doesn't fall if you disconnect the battery. It has a natural resistance to movement that lets the motor turn on for movement and then off once the movement isn't needed. A door lock is similar. The motor just gives a push and a pull to mechanically mimic the motion of your hand pushing the lock. Indents in the lock mechanism are still critical to keep it engaged.

In contrast the vacuum diaphragm is designed to pull steady pressure on the linkage at all times. If the vacuum is disconnected the transfer case will pop out of gear. This is why I doubt you can use a Jeep cable shifter with our transfer cases. You would have to rely on the indent on the handle to hold enough pressure to keep in gear. Even if it would work for a little while any slack in the system that develops would leave you stranded. All the other available Jeep transfer cases, like the NP242 or NP231, stay in gear on their own and just need a push to pop to the next gear. Once it indents inside the transfer case it stays there on its own.

If you run a solenoid to electronically actuate the shifter you would need one that has an internal brake that switchs open during movement and closed when stationary. Such a beast exists, but it is much more complex and bulky than what you are imagining.

Look at the electonic solenoid on the back of an SX4 hatch. It is pretty large and bulky. If you run electricity to it for more than about 2 minutes it will melt all the insulation around the internal wires, in turn destroying it and starting a fire. A smaller solenoid will last even less time switched on. They are designed for a very tiny duty cycle.
Title: Re: Vacuum shift actuator replacement?
Post by: captspillane on July 18, 2012, 09:13:46 PM
A generic door lock actuator pulls or it pushes when you push your door lock button. It doesn't apply any force when you're not pushing the button. It will not apply the necessary constant pressure.

Push a car lock down, it stays down. Pull it up, it stays up. There is something else keeping it from moving. Likewise an XJ transfer case handle gets pulled up to shift, but then you let go and it stays right where you left it. That's not how our Eagle transfer cases work.

Our Eagle transfer cases need a steady one pound of pressure to stay in gear. If they do not they absolutely will pop into a "false neutral." In between gears the car cannot move and damage absolutely will occur. The transfer case will be ruined if you let it pop out too often.
Title: Re: Vacuum shift actuator replacement?
Post by: jim on July 19, 2012, 01:41:30 PM
I think txjeeptx answered the original question, which is that the front axle acuator will not work on the tc without a lot of hassle, so maybe it will be ok to hijack this thread.
I have wondered about a 2 cable system, one to pull the lever either way as needed and lock.
My preferred method would be a solid rod linkage system of some sort.
It's moot for me because either one would be too much for me to fabricate.
Title: Re: Vacuum shift actuator replacement?
Post by: BenM on July 19, 2012, 05:27:01 PM
If you use a lock actuator you would need some kind of over-center spring. It is possible to attach a spring to a lever in such a way that it will pull the lever to either side as long as the motor can overcome the lever and the spring tension to pull the lever to the center and then past it. You would attach the spring so it goes parallel to the lever when the lever is centered.

There are "liner actuators" or "linear motors" that hold in position, but I have no pricing on one or any idea how it would hold up under a car.
Title: Re: Vacuum shift actuator replacement?
Post by: philotomy on July 20, 2012, 09:39:45 AM
I think when the time comes I'll buy a decent used one from a full size jeep,for now I think a cable tied off (or bungee cord)will have to do.
Title: Re: Vacuum shift actuator replacement?
Post by: carnuck on July 21, 2012, 08:14:44 PM
I think txjeeptx answered the original question, which is that the front axle acuator will not work on the tc without a lot of hassle, so maybe it will be ok to hijack this thread.
I have wondered about a 2 cable system, one to pull the lever either way as needed and lock.
My preferred method would be a solid rod linkage system of some sort.
It's moot for me because either one would be too much for me to fabricate.

There is a company that makes them for XJs and others for @$130. I made my own for my FSJ for $40 in parts including a PTO cable from NAPA. (mind you, I got discount on them)
Title: Re: Vacuum shift actuator replacement?
Post by: 85AmCfreak on July 23, 2012, 12:08:50 AM
Do you have a part number casper? Maybe someone could try this out and do a write up??
Title: Re: Vacuum shift actuator replacement?
Post by: txjeeptx on July 23, 2012, 12:26:52 AM
Different mfgrs have used different types of door lock solenoids over the years. I recall the 80's Dodge truck solenoids hold their own position in a latching sort of way. They also snap to between the positions pretty forcefully. Have pinched fingers messin with em on my dad's ol' Ramcharger.

I agree completely that if the solenoid doesn't somehow "latch" itself into position, you'll very quickly burn up the coil  in it (or the supply wire, or fuse, if yer smart enough to remember to include one), since it is an electromagnet, which is essentially a looped-up wire short circuit.

Sure would be cool if the auto-trans shifter cable from some common, junkyard late model application could be easily repurposed into a t-case shifter cable for our Eagles?  -just another idea. Would still need to figure out a shifter handle/lever & mounts for everything.
Title: Re: Vacuum shift actuator replacement?
Post by: BenM on July 23, 2012, 12:07:47 PM
You could use a microswitch to cut the power when it reaches the limit. It would take a small, stiff spring a part of the actuator arm to give you just a bit of play on the engagement or you'd have to be really accurate with the switch placement, but I bet a spring-loaded linkage arm is an OEM part for a ton of stuff. A two-pole microswitch could even illuminate an indicator to tell you you're in position.
Title: Re: Vacuum shift actuator replacement?
Post by: Softbuster on July 23, 2012, 09:53:27 PM
Here is my Idea:  Remove the failing vacuum actuator and install this in its place.  Its a piece of threaded rod, the same size as the Hole in the original mounting bracket, with a chain link (repair-a-link for a bike chain or something) welded on the end.  (you will need the little pin from the actuator to attach it at the shift lever)
The threaded rod is long enough to be able to put the t-case in 2wd or 4wd.   Just that whenever you want to change it you have to crawl under the car with two wrenches and loosen the nuts, move to the desired position and re-tighten the nuts against the mounting bracket on each side.     Or just leave it in 4wd forever!

I like things to be simple and Work every time I want it to.

Question....   should I install this in place of the failing actuator to sell the car or let the buyer decide what to do??



(http://img.photobucket.com/albums/v467/Softbuster/102_0438.jpg)

(http://img.photobucket.com/albums/v467/Softbuster/100_0227.jpg)
Title: Re: Vacuum shift actuator replacement?
Post by: mach1mustang351 on July 23, 2012, 10:35:11 PM
What if someone went with a old school style stick shift and made some kind of detent setup. 

Something that works like if you push the stick to the right it comes out of the detent, pull into 4wd and then let it move back to the left to lock the stick and linkage in place. 

It all makes sense in my head... i'll try to draw a picture
Title: Re: Vacuum shift actuator replacement?
Post by: carnuck on July 24, 2012, 03:12:35 PM
I'm putting an FSJ lever under my seat.
Title: Re: Vacuum shift actuator replacement?
Post by: jim on July 24, 2012, 08:27:37 PM
I'm putting an FSJ lever under my seat.
Attached to what how?
Title: Re: Vacuum shift actuator replacement?
Post by: carnuck on July 25, 2012, 07:56:34 PM
Attached to the floor and tcase, almost the same way as FSJs do. Measure twice, drill hole, fish arm through, put screws into plate around arm cut from FSJ hump. Hook up linkage.
Title: Re: Vacuum shift actuator replacement?
Post by: 85AmCfreak on July 27, 2012, 03:00:32 PM
I would really rather have something look original and work.....which is apparently something that just won't go together. I was just thinking that if I am going to go through the trouble of pulling the shield and getting up there to pull the vacuum motor maybe there is something better that will retain the original look. Unfortunately thats not possible. Looks like I am gonna have to buy that outrageously overpriced shift motor from those wagon dudes.
Title: Re: Vacuum shift actuator replacement?
Post by: Draekon on July 27, 2012, 03:21:09 PM
How much force would a linear actuator need to be able to exert to shift the tcase?
Title: Re: Vacuum shift actuator replacement?
Post by: carnuck on July 28, 2012, 01:07:53 PM
The hi/lo on the 229 is a lever operated setup in FSJs. You could also go under dash with a PTO cable. Maybe rig up the external hi/low electric shift from a later 80's model GM?