Front axle not powered in 4wd

[JLafer]

Hey everyone,

So one afternoon i got stuck pretty bad and tried to 4wd it out. 4WD was working but i was stuck just spinning. Tried to 4WD low and creep it out then heard a snap. No 4WD now.

Since then i have flipped the 4wd air lever and went underneath the truck and spun the shaft and it locks the shaft. tried to turn the flange with a big bar no budge, took the drive shaft off and made sure where the drive shaft mounts to the other flange (PTO) was not snapped and both turned together. they do.

Im wondering what is the most common to break so i don't have to have this torn down for to long. also should i just pull the top of the pumpkin off and see what it looks like? Haven't drained the fluid yet to look for metal chunks, going to do this coming weekend.

Vehicle: 1971 m35a2 bobbed on 52's

Thanks Josh

 

[eagle4g63]

First...PTO is for the winch....you are probably talking about the transfer case....other than that, which flange were you first talking about.....the one on the axle or at the transfer case?

Wheels in the air I hope when you are trying this......


OH yeah, by the way.....WELCOME TO STEEL SOLDIERS!!

 

[Recovry4x4]

If I were to make an educated guess, I would lean towards a front axle. If I were to make the same educated guess on cause, it would be 52" tires.

 

[JLafer]

Sorry for the confusion, i was trying to explain the flange the front drive shaft attaches to on the backside of the axle does spin the front flange on the front of the axle together. if that makes sense.

i THINK i have determined the front drive shaft to axle IS powered when in 4wd. when truck is in neutral and the 4wd is NOT engaged the front drive shaft spins freely. When engaged the front drive shaft is locked and spins when the rear does BUT does not power the front wheels. i did replace all of the front wheel bearing and the axle shafts are not broken.

 

[porkysplace]

Sorry for the confusion, i was trying to explain the flange the front drive shaft attaches to on the backside of the axle does spin the front flange on the front of the axle together. if that makes sense.

i THINK i have determined the front drive shaft to axle IS powered when in 4wd. when truck is in neutral and the 4wd is NOT engaged the front drive shaft spins freely. When engaged the front drive shaft is locked and spins when the rear does BUT does not power the front wheels. i did replace all of the front wheel bearing and the axle shafts are not broken.

You did this since you got it stuck ? You may have broke a axle getting it stuck. Time to breakout the TM's

 

[Rmtaunton]

X2 on axle shaft. With the front axle switch disengaged, lift one tire and spin and make sure drive shaft spins. then repeat on other side.

 

[JLafer]

Yes since it was stuck/happened I have changed the bearing and noticed neither shaft was broken. I was hoping it wasn't an axle but I will go to the TMs. Maybe time for a 5 ton

 

[rosco]

Jack up one front wheel at a time, with it in 4WD. The one that turns, is the one that is broken. Welcome

 

[JLafer]

Jack up one front wheel at a time, with it in 4WD. The one that turns, is the one that is broken.
Welcome

I will do that when i get home, Thanks.

I will post back later with updates. Thanks everyone!

 

[Recovry4x4]

Yes since it was stuck/happened I have changed the bearing and noticed neither shaft was broken. I was hoping it wasn't an axle but I will go to the TMs. Maybe time for a 5 ton

Neither outer shaft was broken but it's quite probable that an inner shaft is broken.

 

[porkysplace]

Jack up one front wheel at a time, with it in 4WD. The one that turns, is the one that is broken. Welcome

Unless it has a locker in it with 1 wheel on the ground the other wheel will spin when jacked up.

 

[JLafer]

Alright guys, i have started the truck and lets the tanks fill up, flipped the little lever for 4wd. Jacked up one side at a time and didnt lock the driveshaft, neither tire spun the front driveshaft.

I dont believe i have a locker in it. i never installed and the guy before me didnt, i first tried the 4wd this winter on my snowy road to see if i had 4wd and while in 4wd only the rears broke loose

 

[Recovry4x4]

Maybe we should get back to basics. Since you have the air shift lever, we were all assuming that you had the air shift transfer case. Since your truck was assembled by someone else, we need to confirm this. Look at the front of the transfer above the front driveshaft. Is there an air hose going to it? If there is, that's good. If not we have other things to discuss. If it is an air shift, you will hear a clunk sound when you engage AWD. Try it with the air supply built up and the truck off so you can hear. The light doesn't need to have power to engage the case.

If all this checks out, you will need to dissassemble the front end. The jack up one side trick won't identify which axle is broken. If you spin the side that isn't broken, it will just spin the spiders. Had there been a locker than it would have shown which was broke. Now it's just a matter of dissassembly and inspection.

 

[JLafer]

Yes there is an air line and intact. If i flip the lever and turn the drive shaft by hand it will lock with a hard clunk and you cant turn it by hand.

 

[Recovry4x4]

That's good news. I feared it having a sprag case. Dissassembly time! I'm sure not what you wanted to hear but ......

 

[JLafer]

its not haha, i love driving it but it needs to be fixed. i guess ill start tearing into it.

ive read alot here and learned about the different TCs and such

 

[sandcobra164]

Do a search for ¨inner axle seal replacement¨ and you'll find a nice FAQ and picture thread showing how to tear down to the level that you need to accomplish your goal. You'll likely have to tear down both sides at the same time so that you can push a rod from the unbroken side to the broken side to remove the snapped inner axle shaft. It's a very simple job but parts are heavy. Air tools are recommended to speed things up but it's not a bad job. If you can't find the thread, try to download the TM. 1. Remove wheel, 2, remove axle flange, 3, remove 3 inch Octagon axle nuts and lockwasher, 4, disconnect brake line from wheel cylinder, 5, remove backing plate nuts and backing plate, 6, remove axle end, 7, pull out axle shaft and cv joint. One will likely be shorter and missing it's end based on the problem description. Since you've torn it down this far, I'd go ahead and replace the inner axle seals. If your axle boots are worn, it's only a matter of removing the king pin bushings and the tie rods to remove the knuckles if you would like to use solid boots. Zipper boots can be installed without tearing anything apart but some have mixed reviews of those. Reassembly is reverse of disassembly. Remember when tightening your axle nuts, torque inner to 50 ft lbs with an assistant turning the drum and then back off roughly 180 degrees. Install lockwasher and torque outer to 150 ft lbs, bend tabs of lockwasher over. Works every time for me.

 

[JLafer]

Awesome info, ill give it a search. Thanks everyone for the information and knowledge so fast!

 

[jeremymx26]

I have the same problem that I need to tear into. Good luck and post some pictures of your conclusion.

 

[m16ty]

Disengage the t-case 6X6 switch. Crawl under the truck and try to turn the driveshaft (you may use a bar to get a good pull on it). If the driveshaft will spin, something in your front axle is broken.

Next engage the 6X6 switch and jack one tire off the ground. If you can spin the tire, your t-case is broken.