Why is my 4wd not working?

[JOHN BUFF]

Hello, got our first snow of the season and my 4wd does not work. I have a 94 bauer x with auto hubs, I do get a light on the dash, and hear what sounds to be something engaging on transfer case, but I had all 4 wheels off the ground today, and the front tires would not move in 4wd.
I checked the connector at the shift motor, and al looks fine. And like I said I do get a light on the dash, and hear something engaging and disengaging at the push of the button.
Thanks for any info

 

[Blee1099]

its more than likely your auto hubs.. Is there a ratcheting sound or a high pinch sound coming from them when you got it in 4wd?

 

[JOHN BUFF]

There seems to be no force comming from the transfer case to make the front wheels move. Last year I did have some clicking from the drivers side hub. I am ready to replace both hubs if need be. But I believe the problem is before the front driveaxle.
And thanks for the quick reply, and your time.

 

[MrShorty]

There seems to be no force comming from the transfer case to make the front wheels move. Last year I did have some clicking from the drivers side hub. I am ready to replace both hubs if need be. But I believe the problem is before the front driveaxle.
And thanks for the quick reply, and your time.

When you had it off the ground, did you see the front driveshaft spinning when the t-case claimed to be in 4WD? If you crawl under it with the t-case in 2WD (engine off) and spin the front driveshaft, does it spin indefinitely, or does it spin a couple of turns until the hubs engage and stop?

 

[DeRocha]

I'd just put a piece of tape on the front drive shaft and then engage 4x4 for 50 feet or so and see if the tape moved.

 

[JOHN BUFF]

Hello again, after lowering the truck and going inside the house, I thought later that I should have checked to see if the front shaft was turning when hit the gas, but all I did was stick my head out the window to look at the rear tires, as well as the fronts.
I try it later today, and then post reply.
Thanks again..
P.S. the tape sounds like a good idea.

 

[JOHN BUFF]

Hello again, well I tried the tape idea and it seems the shaft did move. I drove the truck arround the block, and engaged the 4wd while driving (4wd light at button lit as well as 4x4 light in dash). Although I did not notice any noises whatsoever, like something engaging. Also there seems to be no additional drag on the motor (or RPM change) after I engaged 4wd. As I said the shaft WAS in a different position, but I don't believe it spun with any torqe.
Thanks again.

 

[DeRocha]

One or both or your autohubs are gone (failing to lock with their respective axle shaft(s)). Open differentials send power to the wheel with the least resistance. Since one HUB has failed to lock it is the one getting all the power. It's Axle shaft is just spinning freely and therefore you will feel very little if anything from the front. So basically if you have open diff and you break a hub, then you only have a 4x2 since the front will be ineffective.

 

[JOHN BUFF]

Hello, thanks for the info..Last winter I heard some severe clicking in the area of the drivers side hub. I will purchase a new one this week to replace it. I'm hoping the passenger side will still be good. I can understand the theory of the power going to the side of least resistance.
Wish me luck.

 

[Robb]

When pricing that replacement auto hub, remember that you can replace both sides with Warn manual hubs for about $200 (DIY), and you will never have to worry about hubs not engaging again.

 

[JOHN BUFF]

I had no idea about the maunal hubs, can you tell me more about these? I have about 25 years experiance working on my cars .. and feel capable.. are you saying if I convert to manual.. I can still control the 4wd by the button on the dash. or will there be locks that need to be turned on the hubs themselves.
Thanks for the info

 

[Robb]

You can do a search on these forums for "warn manual hubs" and you will find LOADS of information about them. The auto hubs are very prone to failure, and eventually will break. The replacement cost of a new (or rebuilt) auto hub will probably be more than the cost of switching over to manuals. And to be honest, after you replace that one, the other one will fail when you will need it the most (Murphey's Law).

The Warns will run about $150 for the hubs themselves, plus about $50 for the install kits. You can order them from various dealers online, but I believe NAPA is also a Warn dealer (although they may run a little more $$).

Yes, you will need to physically engage the hubs at the hubs themselves. BUT, if you are heading out into a situation where you feel you will probably need 4wd, you can engage the hubs without engaging the t-case (pushing the button). You can drive like this for quite awhile, then when you actually need 4wd, you can push the button and you will have 4wd.

There are write-ups on here describing the swap procedure, but the instructions that come with the hubs explain it pretty well. It isn't complicated at all.

Good Luck!

 

[agzaretzka]

Before spending money on new hubs of either variety, first inspect your old ones. They may just need a thurough cleaning (also well documented here) !!!

 

[DeRocha]

The manual HUBS are the way to go.. As Robb mentioned one autohub cost the same as getting 2 new manuals along with the installation kit. The manual Hubs are also many times stronger than the Autos. The only down side is that you need to leave the cab and turn the hubs manually to lock them. IMO this is a minor inconvenience/trade off for the strength and reliability that the manuals bring to the table.

As noted by agzaretzka you should remove the autohubs and inspect them for damage or excessive grease. Grease is the enemy of autohubs and all too often a factor in their failure. A build up of grease will cause the autohub to become hydrolocked and prevent the hub from engaging. You can check out the maintenance link in my sig to see lots of good info on this subject.

 

[JOHN BUFF]

Thank you all for the EXCELLENT INFORMATION. I have a few NAPA's in the area if I decide to go with the manuals. But I noticed in the end of Derocha's post he talks about the grease. I may have screwed up a few months back when I repacked my bearings, I believed I also packed the hub generously.
If this is true, and it is stopping this hub from engaging, maybe it causing an open-ended situation with the front transaxle..PS the best price I found for a direct OEM auto hub was 205.00.
Once again thank you guys for your time, this is a great website!

 

[DeRocha]

That will do it

The hubs will not function correctly or at all if there is any grease compressed in the end. If you or your mechanic have a habit of generously coating the splines on the stub axle with grease, give it up. The only thing the grease is for is to keep the splines from rusting. In normal service, the only time anything slides on the splines is when you assemble the hub to the rotor.

You have nothing to lose by cleaning them. I would take the hub off and flush/soak it with paint thinner to remove as much grease as possible (I have done this several times on my Autohubs and they still work fine). I would then soak it in a few ounces of ATF for a while (1/2 hrs or so) to help lubricate the bearing hidden from view at the very end of the hub.

 

[JOHN BUFF]

Well I got some good news and some bad. I replaced both auto locking hubs, and still have no 4wd!!. Any suggestions as to what I should check next? Like I said, I do get a light on the dash and button area for the 4wd, and from what I read in other posts, that only tells me that there is contact at the shift motor. I DO NOT get any light (or change) for the 4wd Low button. I'm guessing that what the shift motor is for, is to engage a gear or two in the transfer case to supply the front wheels with power. I have never removed the shift motor, only thing I've done in that area was pull the plug apart to check the connections.
I just landed some more tile work out of state, and I will be needing my 4wd within a month (snow).
Thanks to all for your info.

 

[MrShorty]

There aren't too many failure points in the front drivetrain.
1) Does the t-case power the front driveshaft? Presumably the tape on the driveshaft test confirmed that the front driveshaft is powered by the t-case. If there's any lingering doubt, verify that the front driveshaft if powered. If not, then the problem is in the t-case. If yes, then continue.
2) Are the axleshafts getting power? Do they both rotate with the driveshaft? If not, then there's a problem in the differential. If yes, then continue. Be sure not to let the open differential cause confusion.
3) Are the wheels powered by the axleshafts? If not, then there's a problem in the hubs. If yes, then the 4WD is working. But the 4WD isn't working, so if we get to this point, we need to go back and figure out what we did wrong.

In essence, I would suggest isolating where power transmission is failing in the front drivetrain. We thought we had it isolated to the hubs before, but now we're not too sure.

Good luck.

 

[Splorer Man]

back yard test

if you have a LS rear jack up both rear wheels,and one front.Put it in 4X4,then in gear,the front and rear wheels should turn.Check to make sure the front drive shaft is turning.If it isnt,the shift motor is bad(or a bad connection),You should also hear some relays clicking while is going into 4X4 when you push the button.I hear the relays and my 4X4 works fine.I have a 94 with manual hubs

let us know how you make out

 

[DeRocha]

Please clarify the new autohub install. Did you install 2 brand new autohubs along with new nylon engagement cams? Time for some more tape.. Put some tape on the axle shafts going into each wheel. This will let us know if the diff is working and rotating the shafts....

Note: As a safety feature you can only engage 4x4 low if your in neutral or park (and speed < 3mph). Low range will scream at speeds approaching 20mph...