4x4 engaging but not spinning tires - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > 4x4 engaging but not spinning tires

SPARTAN LOCKERS are on sale BIG TIME at ROCKRIDGE 4WD!ROCKRIDGE4WD Introduces a NEW Jeep Wrangler JK *led* tail ANOTHER Rockridge4wd Creation!! Spare Tire Carrier Delete

Reply
Unread 12-13-2011, 04:59 PM   #1
redbullrr
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2010
Location: BrentWood
Posts: 100
4x4 engaging but not spinning tires

Today I tried to tackle the grinding noise I keep hearing anytime I try and start the jeep. Lifted truck up entirely took starter of and mounted back on seems to work better...

Tried to test and verify that all 4 wheels are spinning considering snow is coming soon I want this working.

To my surprise no it does not spin the 4 tires with 4H engaged. You can see it spinning the driveshaft that goes for the front wheels but not the tires. Wtf?! Anyone have clues to this? Also the rear driver side tire only spins when I give it has and seems to get hung if pressure is put on it. The passenger side rear spins great when in gear. Any help would be greatly appreciated!

redbullrr is offline   Reply With Quote
Unread 12-13-2011, 05:10 PM   #2
dillonjm
30mm @ 70/sec
 
dillonjm's Avatar
2003 TJ Wrangler 
 
Join Date: Jun 2003
Location: Warrensburg, MO
Posts: 3,908
Quote:
Originally Posted by redbullrr View Post
Tosh I tried to tackle the grinding noise I keep hearing anytime I try and start the jeep. Lifted truck up entirely took starter of and mounted back on seems to work better...

Tried to test and verify that all 4 wheels are spinning considering snow is coming soon I want this working.

To my surprise no it does not spin the 4 tires with 4H engaged. You can see it spinning the driveshaft that goes for the front wheels but not the tires. Wtf?! Anyone have clues to this? Also the rear driver side tire only spins when I give it has and seems to get hung if pressure is put on it. The passenger side rear spins great when in gear. Any help would be greatly appreciated!
Sounds like your 4x4 vac actuator on the axle isn't engaging the collar to connect the inner and outer shaft. I would bet the inner p-side shaft is spinning, you just can't see it, as that is the path of least resistance.

An open differential sends power the path of least resistance as you're seeing in the rear as well.
__________________
03 Rubi on 35's (Weekend Toy)

11 Ram 2500 - 6.7 Cummins (DD/Tow Rig)

05 Liberty Limited (Wife's): Minor mods, OME/JBA Suspension, 245 70/17 Duratracs
dillonjm is offline   Reply With Quote
Unread 12-13-2011, 07:07 PM   #3
Poke
runtime error = 0
 
Poke's Avatar
2015 YJ Wrangler 
 
Join Date: May 2008
Posts: 3,083
Your vacuum disconnect is failing. You have 4 options to fix it.

Replace it with a new/rebuilt actuator

Install a cable system(problem ridden in my experience)

Permanently engage the fork by moving the e clips.

Install a one piece axle shaft from a tj or xj.


You might just have a vac leak in the line from the tcase to the vac actuator. I would start here by looking for this leak.
__________________
Quote:
Originally Posted by ionakana
don't post threads that poke Poke!
Poke is online now   Reply With Quote
Unread 12-13-2011, 11:36 PM   #4
Anticanman
Follow me
1994 YJ Wrangler 
 
Join Date: Aug 2009
Location: Ripon, California
Posts: 19,223
Quote:
Originally Posted by Poke View Post
Your vacuum disconnect is failing. You have 4 options to fix it.

Replace it with a new/rebuilt actuator

Install a cable system(problem ridden in my experience)

Permanently engage the fork by moving the e clips.

Install a one piece axle shaft from a tj or xj.


You might just have a vac leak in the line from the tcase to the vac actuator. I would start here by looking for this leak.
This ^^^

Your four options can be obtained for cheap as well.
__________________
Luck Favours The Prepared
[SIGPIC][/SIGPIC]
Anticanman is offline   Reply With Quote
Unread 12-14-2011, 03:27 AM   #5
Mark05059
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: quechee Vermont
Posts: 4,266
well everything may be all right if the jeep wasnt running? Was the jeep running when you put it into 4x4 on the transfer case? If it was running then yes the above is correct. If it wasnt running then redo your test with the engine on.
__________________
1998 ZJ 5.2 Auto

1989 Wrangler Black Bone Stock 2.5l 5spd
/l , [____],
|---L--[]lllllll[]-
()_) ()_)==O=)_)
Mark05059 is offline   Reply With Quote
Unread 12-14-2011, 06:26 AM   #6
redbullrr
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2010
Location: BrentWood
Posts: 100
I'm new to this and the service manual isn't helping me. We're am I looking for this vacuum line?
redbullrr is offline   Reply With Quote
Unread 12-14-2011, 06:37 AM   #7
grandboost98
Registered User
1989 YJ Wrangler 
 
Join Date: Aug 2010
Location: Durham/East Haven, CT
Posts: 2,941
from the front axle actuator going to the transfer case there should be a few vacuum lines
__________________
89 Jeep Wrangler - 3.5" HD BDS lift and M.O.R.E. HD 5/8" booms on 33s
99 Jeep Cherokee - 2 door, 5" lift on 33" super swampers
72 Chevy Nova - build in progress
98 Pontiac Grand Prix GTP - too many mods to list::SOLD::
grandboost98 is offline   Reply With Quote
Unread 12-14-2011, 10:35 AM   #8
redbullrr
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2010
Location: BrentWood
Posts: 100
Quote:
Originally Posted by Mark05059
well everything may be all right if the jeep wasnt running? Was the jeep running when you put it into 4x4 on the transfer case? If it was running then yes the above is correct. If it wasnt running then redo your test with the engine on.
Jeep was running all four tires lifted the drivers rear only moved when giving it has in gear the passenger rear moved in gear no gas and the front driveshaft spins but the front wheels do not move.
redbullrr is offline   Reply With Quote
Unread 12-14-2011, 11:09 AM   #9
Anticanman
Follow me
1994 YJ Wrangler 
 
Join Date: Aug 2009
Location: Ripon, California
Posts: 19,223
Sounds like a CAD problem. Are you in Brentwood in the bay area? If so, come over to Tracy and I'll get you a prelocked CAD unit or lock it for you at my shop.
__________________
Luck Favours The Prepared
[SIGPIC][/SIGPIC]
Anticanman is offline   Reply With Quote
Unread 12-14-2011, 12:37 PM   #10
GrantYJ
Registered User
1992 YJ Wrangler 
 
Join Date: Mar 2009
Location: Neosho, Missouri
Posts: 837
Quote:
Originally Posted by redbullrr View Post
I'm new to this and the service manual isn't helping me. We're am I looking for this vacuum line?
On the top/rear side of the passenger side front axle tube (just in from the leaf springs) there is a big doohicky. That doohicky is your vaccuum actuator. From the actuator, there are two hard plastic vaccuum lines that run back to your transfer case vaccuum switch. There is a good chance that your problem is somewhere between these two points. Start the Jeep, put it in 4H, (out of gear) and pop one of the lines off. If there is no vaccuum, put it back on (they just slide in and out) and check the other one. If one of them does have vaccuum, then follow Poke's advice in post #3 because it sounds like your actuator is shot. If neither of them have vaccuum, check for vaccuum at the transfer case switch (just follow the lines and you'll find it).

If you have it at the switch, it's your lines (they are easily cracked or broken) which can be very easily patched using normal rubber vaccuum lines. I don't remember which size, just buy a foot of the sizes that look close and see which is a good fit. I normally get about 1/4" of the hard line inserted, then spread on some RTV sealer on the hard line and shove it in for another inch or two. If it's a line issue, start your search for problems near the exhaust pipe and cat (that's where they normally fail). You might want to run new lines if they're brittle.

If you don't have it at the switch, check the other lines that run into the transfer case switch to see if vaccuum is present there (one is just a vent, the other is your vaccuum source which runs to the gray vaccuum tank under the brake booster). If there is vaccuum from the source, your switch is bad. If there is no vaccuum there, start backtracking to the cannister and the engine.

vacuumdiagram-4wheeldrive-frontaxle.jpg
GrantYJ is offline   Reply With Quote
Unread 12-14-2011, 12:47 PM   #11
redbullrr
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2010
Location: BrentWood
Posts: 100
Quote:
Originally Posted by Anticanman View Post
Sounds like a CAD problem. Are you in Brentwood in the bay area? If so, come over to Tracy and I'll get you a prelocked CAD unit or lock it for you at my shop.
I'm actually in Brentwood, however it's New York :-(
redbullrr is offline   Reply With Quote
Unread 12-14-2011, 12:50 PM   #12
redbullrr
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2010
Location: BrentWood
Posts: 100
Would the Driveshaft still spin even though the tires dont? I'll take a look later today and give feedback.
redbullrr is offline   Reply With Quote
Unread 12-14-2011, 02:13 PM   #13
Anticanman
Follow me
1994 YJ Wrangler 
 
Join Date: Aug 2009
Location: Ripon, California
Posts: 19,223
Quote:
Originally Posted by redbullrr View Post
Would the Driveshaft still spin even though the tires dont? I'll take a look later today and give feedback.
Power can be sent to the differential and then to the passenger side stub without being diverted to the drivers side at all. That's the point of an open differential, to allow the wheel with the least resistance to get the power. Or in this case the stub not connected to a wheel.
__________________
Luck Favours The Prepared
[SIGPIC][/SIGPIC]
Anticanman is offline   Reply With Quote
Unread 12-14-2011, 02:17 PM   #14
GrantYJ
Registered User
1992 YJ Wrangler 
 
Join Date: Mar 2009
Location: Neosho, Missouri
Posts: 837
Quote:
Originally Posted by redbullrr View Post
Would the Driveshaft still spin even though the tires dont? I'll take a look later today and give feedback.
Yes...

As explained above, your axle shaft on the passenger side is not one piece. It's two axle shafts that get locked together by a sliding sleeve/collar. If the sleeve/collar for whatever reason (lack of vaccuum, bad vaccuum motor, bad vaccuum switch, and etc.) is not sliding into position, then your front axle is turning, and only one axle shaft will turn (just like in the back) because you don't have lockers...

Since one axle shaft has a big old wheel and tire hanging on it (driver's side wheel and tire = resistance), the spinning motion from the drive shaft all gets transmitted to the passenger side shaft (through the spider gears)... Since that shaft isn't engaged to the outer shaft through the sleeve/collar, the passenger side inner shaft (next to the pumpkin) will be spinning like mad without either of the tires turning.

If you want to test this, get it going in 4H, and manually start spinning the driver's side tire forward. It won't be hard to turn and if your wheel/tire is small enough, it will probably keep spinning as long as you leave it running.
If that doesn't work, take off the driver's side tire and repeat the test outlined above and it will. You'll see the driver's side spinning.

The only exception to what I've stated above is if you'd broken something in the front end. I strongly doubt that this is the case, because if it had, you'd be talking about the horrible sounds it was making.
GrantYJ is offline   Reply With Quote
Unread 12-14-2011, 02:21 PM   #15
redbullrr
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2010
Location: BrentWood
Posts: 100
Quote:
Originally Posted by GrantYJ View Post
It can... As explained above, your axle shaft on the passenger side is not one piece. It's two axle shafts that get locked together by a sliding sleeve/collar. If the sleeve/collar for whatever reason (lack of vaccuum, bad vaccuum motor, bad vaccuum switch, and etc.) is not sliding into position, then your front axle is turning, and only one axle shaft will turn (just like in the back) since you don't have lockers... Since one axle shaft has a big old wheel and tire hanging on it (driver's side wheel and tire = resistance), the spinning motion from the drive shaft all gets transmitted to the passenger side shaft (through the spider gears)... Since that shaft isn't engaged to the outer shaft through the sleeve/collar, the passenger side inner shaft can be spinning like mad without either of the tires turning.

If you redo your test, get it going in 4H, and manually start spinning the driver's side tire forward. It won't be hard to turn and if your wheel/tire is small enough, it will probably keep spinning as long as you leave it running.
I did that for the rear, and worked. The front's just dont spin at all, meanwhile the front driveshaft is spinning when I put it in 4H so more then likely a bad vacuum. How hard is it to install 1 of these Posi Locks?
redbullrr is offline   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.