Jeep Wrangler Forum - Reply to Topic
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ Tech Forum > Vacuum shift motor inexpensive fix

Join Wrangler Forum Today


Thread: Vacuum shift motor inexpensive fix Reply to Thread
Title:
  
Message:
Post Icons
You may choose an icon for your message from the following list:
 

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Additional Options
Miscellaneous Options

Topic Review (Newest First)
08-29-2014 05:34 PM
Coyote_94YJ
Quote:
Originally Posted by jasperpickels View Post
I can't turn it by hand when it is sitting still. It's not spunky freely like your saying by friction or momentum. It's spinning because it's locked I'm guessing. But I'm not sure why it's locked and I'm not sure how to unlock it, the vacume lines are hooked up and are fairly new.
Have you done the mod in this thread or can you verify if a previous owner has done this mod or not? Doing this mod WILL lock your driveshaft to the front diff and subsequently the front tires causing it to spin like you are describing. That is normal. If the mod has not been done your problem could be one of two things: the vacuum lines are hooked up wrong, your transfer case is not coming out of 4WD completely. There are a couple ways to test to see where the problem is. One way is to jack up just the front tires with the transmission in gear and try to spin the front shaft. If it spins and the front tires spin (as in the two are locked together) the problem is in vacuum shift motor area of the front axle. If the driveshaft doesn't spin at all and is locked in place, your problem is in the transfer case. The other way is to remove the vacuum lines from the front diff and see if that frees up the front driveshaft. If so, chances are your vacuum lines are not hooked up properly. If not, the problem could still be in the front diff as in your vacuum shift motor could be stuck. Or it could be in your transfer case.

I suspect that since the lines look fairly new that they were replaced and didn't get hooked up properly or the mod described in this thread has been accomplished. There is a slight possibility that your transfer case shifter is out of adjustment but I doubt it.
08-28-2014 03:45 PM
dmaxthad So my 92 decided to not get any vacuum to the front drive line the day before leaving to deer camp. I stumbled across this thread and just so happened to have a perfect spring in my tool box. If any of you guys do a shift kit or transmission build on an allison 1000 the springs out of the valve body are perfect. HAHA
08-28-2014 02:25 PM
jasperpickels
Quote:
Originally Posted by Coyote_94YJ View Post
It will always spin to a certain extent due to friction in the bearings, chain, oil viscosity, etc. inside the transfer case. Is the front driveshaft physically locked in as when the jeep is parked (trans in gear, t-case in 2WD) you cannot turn the shaft by hand?
I can't turn it by hand when it is sitting still. It's not spunky freely like your saying by friction or momentum. It's spinning because it's locked I'm guessing. But I'm not sure why it's locked and I'm not sure how to unlock it, the vacume lines are hooked up and are fairly new.
08-28-2014 01:50 PM
Coyote_94YJ
Quote:
Originally Posted by jasperpickels View Post
my front driveshaft on my YJ is spinning consistently when im in 2wd. my 4wd is working fine 4h and 4L. But the front drive shaft isnt supose to be spinning in 2wd. CAN ANYONE PLEASE HELP ME SOLVE THIS? I have ben trying to for the past two weeks and cannot figure it out al my vacume lines are hooked and i just put a new tcase in it yesterday. HELP PLEASE!!
It will always spin to a certain extent due to friction in the bearings, chain, oil viscosity, etc. inside the transfer case. Is the front driveshaft physically locked in as when the jeep is parked (trans in gear, t-case in 2WD) you cannot turn the shaft by hand?
08-28-2014 01:17 PM
jasperpickels my front driveshaft on my YJ is spinning consistently when im in 2wd. my 4wd is working fine 4h and 4L. But the front drive shaft isnt supose to be spinning in 2wd. CAN ANYONE PLEASE HELP ME SOLVE THIS? I have ben trying to for the past two weeks and cannot figure it out al my vacume lines are hooked and i just put a new tcase in it yesterday. HELP PLEASE!!
11-25-2013 02:36 PM
Coyote_94YJ To you guys who are welding the shift collar to the axle... I hope you are not welding to the outer axle shaft at all. Not even remotely a good idea. If you have to remove the axle shaft for any reason you are totally screwed. There are some simple jobs like replacing the outer axle seal or replacing the steering u-joint that require you to pull the axle shaft and if you've welded the collar to the outer axle seal you are just going to have to buy and install a whole new axle assembly because that shift collar will not pass through the axle tube. Please make sure you are just welding to the inner axle shaft.
11-25-2013 02:21 PM
Coyote_94YJ
Quote:
Originally Posted by AlaskanTimberWolf View Post
Thanks, Coyote_94YJ! This mod fixed my issue wonderfully! I did make one slight modification to the original idea... I placed a metal washer over the vacuum spindle, between the end of the spring and the inner face of the fork. Seems to strengthen / stabilize the fork better. Very strong fix!
Glad it worked for ya.
11-25-2013 01:42 AM
AlaskanTimberWolf Thanks, Coyote_94YJ! This mod fixed my issue wonderfully! I did make one slight modification to the original idea... I placed a metal washer over the vacuum spindle, between the end of the spring and the inner face of the fork. Seems to strengthen / stabilize the fork better. Very strong fix!
07-16-2013 09:37 PM
brachilius A Dana 30 will do fine if you are not heavy on the throttle and stay at 35" tires or smaller. You are correct, crazy rock crawling with a v8 will explode a Dana 30.
07-16-2013 09:27 PM
indirocz28 You do realize that without the posilock engaged you weren't truly in 4wd right?

Also, I think it is possible to pull the axle out with the collar on it. If not, oh well. Many people have welded those collars over the years and they have held fine for regular use age. Unless you're heavy duty rock crawling, I wouldn't worry too much.

Then again, why are you doing heavy rock crawling on a D30?
But breaking axles or u joints does happen so that I guess would be one thing to think of.
07-15-2013 09:37 PM
brachilius Welding the collar to the axle makes no sense to me. If you are out wheeling and blow a u-joint or or break a shaft, this will be a pain to fix. Especially if it is the inner shaft. Considering that a posi-lol can be purchased for about $125, this makes the most sense. I did a lock rite with a posi-lok. It was my daily driver for 7 years. It worked great. I never engaged the posi-lol while driving on road in PA snow. But off road, it was a beast with a rear locker. Most times, I could go anywhere with it in 4wd with engaging the posi-lok. Hill climbs, rocks, and mud were a breeze with the posi-lock engaged.
07-15-2013 08:44 PM
adhammer Yeah thats all I was gonna do was tack weld it actually have a friend do the weld but i want it to where I need to I can find a way to cut welds if I need to replace a axle or something
07-15-2013 08:06 PM
indirocz28 I just depot welded the collar to the short shaft in 4 places. Let it cool.

It works just fine. I've wheeled it several times, and its been good.

No reason to go overboard or anything super heavy. All you need is for that collar to stay in place to the left.
07-15-2013 03:33 PM
adhammer
Quote:
Originally Posted by indirocz28 View Post
I was just going to comment and say that yes, the front DS does spin now.

I slid the collar to the left, tack welded it in 4 places around the axle, and cut off the forks on the modulator arm. Put it back together and BAM! 4WD!
Did you heat treat it after wards
07-10-2013 08:01 PM
adhammer Well got it in but when It sits and I kick it in 4wd I got a grinding noise at 1st guess the spacer I used isn't shoving the forks over far enough guess I'll try to weld the collar in place haha
07-09-2013 02:50 PM
indirocz28 Just take one of your others to Lowes or home depot. Or a local bolt store.
07-09-2013 10:40 AM
adhammer Would anyone one know what size bolts are used I broke the head off one Dana 30 axle?
07-01-2013 04:24 PM
Coyote_94YJ The original switch for the 4WD light is on the axle disconnect that you put the spring in. That's the 2 wires that go to the front axle. If you can find a 2 wire normally open detent(ball type) switch with the same thread pitch as the vacuum switch, you could replace it and run the two wires to that and it should work.

Probably something like this.
Item # 21-385, Precision Ball Switches- Normally Open, Exposed Terminal (Stud Terminals) On Pollak

I don't know what the thread pitch on the vacuum switch is but this is 9/16-18. If it fit, you could put a thin nut on it so you could adjust the depth to just the right spot.
06-30-2013 07:53 PM
STAN1990JEEP The spring fix worked great !!!!! I noticed that both wheels were turning right away in 2 wheel drive. When I put it in 4 wheel drive it worked great. Thanks for the idea. Now I have to replace the vacuum switch on the transfer case some time to make the 4x4 dash lite work. Any ideas on that without making it work by vacuum ? Thanks again.
06-24-2013 11:49 PM
Keymo
Quote:
Originally Posted by RandomYJguy View Post
So I have several questions,

When I engage my 4wd, aren't both axles spinning? Both my front tires should be spinning while engaged? By doing this spring (or spacer) coversion and having my front axle always spinning, do I need to engage the 4wd when I go through mud? So many questions for this inexperienced guy haha
Yes, you still need to engage you T-case to get your 4WD to actually engage... The spacer/spring are just making it so that your Vac. lines aren't controlling if your passenger side (and since it's a differential - and driver side) are getting engaged. You're driveshaft will be getting engaged - but no torque will be getting applied from you T-case UNTIL you engage you T-case.

As said before - you're axle/driveshaft will not be engaged - but your driveshaft will be spinning since both sides of the axle are engaged now. Just like the TJ and all model "Wranglers" after the except the YJ... BUT 4WD still not apply UNTIL you engage the T-case...


For the thread:
I had a long talk with the parts store dude who used to be a Hummer mechanic in the military (not the p#ssy hummers on the streets nowadays) and he and I came to the conclusion that a piece of differential breather hose will work as well. (Plus most parts stores will give you a piece for free from their "scraps") Just cut it down to the length that you need it - it's the correct diameter interior to allow the shift motor shaft to fit through - will work as well. That's what I used. I plan on removing and checking the shift motor in a year or two and making sure that the hose is still holding up... But it's worked for me so far.
06-24-2013 11:14 PM
RandomYJguy So I have several questions,

When I engage my 4wd, aren't both axles spinning? Both my front tires should be spinning while engaged? By doing this spring (or spacer) coversion and having my front axle always spinning, do I need to engage the 4wd when I go through mud? So many questions for this inexperienced guy haha
06-17-2013 01:58 AM
camshaft
Quote:
Originally Posted by Coyote_94YJ View Post
You won't be able to tell the difference.

The driveshaft does spin while driving. It spins because the left and right side tires are now directly connected to the differential.
Yeah I wasn't paying any attention when I wrote that but either way 4 wheel drive is back haha
05-29-2013 07:15 AM
indirocz28 Where are you located?

Sucks that you have that much rain, but there must be some great scenery.
05-29-2013 02:07 AM
Keymo Haha! Thought about it - but it's rained almost every day for the past few weeks...

Not that I'm against driving in the rain - but I don't want rain POURING into my truck wherever it sits.
05-28-2013 11:02 PM
indirocz28 Why don't you just drive the j truck without doors?
05-28-2013 09:13 PM
Keymo
Quote:
Originally Posted by indirocz28 View Post
There isn't much fluid that comes out if you face the front end down (jack up the back end a little, and make sure the passenger front side is higher than the left. Then probably almost no fluid would come out.

Anyway, I would use a dial caliper to measure the thickness of the rod, then push the fork over to where it needs to be, and measure from the passenger side (inside of the housing) to the fork.
Thanks! I was THINKING about doing that - but was still annoyed by the fact I'd have to replace the CAD housing and take everything apart again. Due to the INSANELY humid central Iowa weather at the moment - I'd be driving to my Dad's house to work in his garage - and the hardware store I was referring to earlier is on the way... That's why I asked. I may just drive around until I find the spacer I need or one that I can cut down.... Unless someone answers about the spring they purchased...

I just want to do the "job" once - which is actually why my J-truck is immobile right now - waiting for window corner window weatherstripping which is on backorder so I don't have to take the door apart more than once. As of now when I drive it the passenger window randomly comes off it's track and falls to the bottom of the door (luckily it hasn't broken yet) - I'm waiting on the order to replace 100% of the weatherstripping on BOTH doors at the same time....
05-28-2013 09:03 PM
indirocz28 There isn't much fluid that comes out if you face the front end down (jack up the back end a little, and make sure the passenger front side is higher than the left. Then probably almost no fluid would come out.

Anyway, I would use a dial caliper to measure the thickness of the rod, then push the fork over to where it needs to be, and measure from the passenger side (inside of the housing) to the fork.
05-28-2013 08:34 PM
Keymo SO I did the Nutter bypass and the "Team Rush" upgrade about a year ago with plans to keep all of the vac lines and electrical stuff "in place" for if I ever needed to switch back for emissions - but an getting sick of all the crap under the hood now that I've worked on the engine a multiple times with vac lines getting in the way - so NOW I'm planning on eliminating everything that's not necessary to drive DD as I'm not in and don't plan on moving to an emissions state any time soon...

I was just wondering - would you, Cyote_94YJ or anyone, happen to know the actual dimensions of the spring used in the original tutorial (or any other that have done it?). I keep debating whether I want to use the spacer or spring as I don't KNOW if anywhere around me would have the 1/2"x.375x5/8" spacer in stock (or even how to tell them that's what I want - NAPA "know how" is bullsh!t...(along with any other parts stores around here)). There's an AMAZING hardware store - but I doubt they have the nylon spacers... They normally deal with actual HARDWARE....

MyYJ is currently my DD - and I'm not able to use mt J-truck (my other vehicle) to drive to ANY store at the moment - so I would need to know what to get beforehand as it'd be annoying to take the CAD off, measure, and then replace it (with RTV) and fill with fluids just to drive 10-15 minutes to take it off and do the whole process over again (and deal with the messy RTV)... If I can't get a measurement I'll go with the nylon spacer as the measurement were provided - but it'd just help with my constant indiciv-ness.

Thanks in advance!
05-19-2013 02:28 PM
Coyote_94YJ This is true. Dunno why I didn't think of that. It would function the same way a TJ with a front locker would.
05-19-2013 04:33 AM
indirocz28 That is what I was thinking, but then again, why would it function any differently than a TJ or non CAD XJ front axle. When they have lunch box lockers put into them, they still function normally until put into 4wd and torque is applied through the front driveshaft.
This thread has more than 30 replies. Click here to review the whole thread.

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -5. The time now is 01:34 AM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC