Open differential on front or something broken - Diesel Forum

91diesel · 11-11-2007, 11:24 PM

Ok...

Brother got 2 ton forklift sunk a foot or so in mud. Hooked my truck up to it and started pulling. Acted like it was in 2wd but you could feel a little bit of pull from the front. Neither front tire spun. The rear passenger side spun as usual. I know the rear is open but didnt think front was that bad. NEITHER SIDE WAS SPINNING! I stopped after a bit of pulling and got a newer truck and got it out after some pulling.

If i put it in 2wd, floor it on stones in driveway it will spin the tires. 4wd will get you going VERY little spin, if any. 4lo really gets you going. Everything works alright but when it was pulling on that forklift it just wouldnt budge the front end. I thought at least one of the tires would spin. (before you ask, i did have hubs locked)

Anyways...how do the hubs work? Mine are just an easy turn, are they supposed to be easy? Is it just that the front differential was slipping too much or one of the hubs is weak and allowing that side to spin with tire unlocked? I could feel the gears in the tcase engage and disengage so it is working good.

I am going to hitch it up to an almost over-full metal waste dumpster (try 10 tons [img]/forums/images/%%GRAEMLIN_URL%%/smile.gif[/img] and have someone see if the front driveshaft is turning.

Something broken in front differential???

It will move the truck about VERY good by itself but under that load it wouldnt budge.

Greg77 · 11-12-2007, 01:47 AM

There are splines on the front drive shafts that do strip out. Also I had a spline strip inside the front pumpkin on the passenger side. Also take apart your hubs and make sure they are all good. More than one guy has run the front end out of oil and ruined it.

Phillipmc1268 · 11-12-2007, 01:58 AM

In a safe area, jack up the rear end with a floor jack under the rear differential and see if your truck will move in 4WD.

If I were a gambler, I'd bet on a broken or stuck hub. A locking hub just has a collar with internal splines to engage the axle and external splines to engage the spindle. There is a spring attached to the actuator so that when you turn it to lock, spring pressure is held on the collar until the splines line up, at which point it locks in. If either hub doesn't engage, neither tire pulls unless you have a locking differential. Since you don't feel much resistance I suspect the spring is broken.

There are no clutches to slip in the hub or front differential that would keep at least one wheel from turning. Open differentials don't have clutches at all and pos units only use them to make both front wheels turn. Front pos units are very rare from the factory and even if you have one wearing one out would take a very long time in a part time 4WD truck.

91diesel · 11-12-2007, 05:02 PM

Well looks like my diffrentials and hubs are fine, jacked it up with a forklift and hit 4wd. All tires spun some and put foot on one side of front the other spun fast.

Also hooked it up to metal dumpster and pulled in 4 lo. 4HI wouldnt move 4 lo made both passenger tires spin.

Sigh....i guess its something ill have to live with. Not like im gonna be pulling anything that heavy much anyways.

94_turbo · 11-12-2007, 09:53 PM

something broke in the transfer case???

91diesel · 11-12-2007, 10:58 PM

No i figured it out today...it just didnt have the guts in the diffrential or it wasnt locked in gear from the cab which i think it was. I think its just normal because theres not positraction or and locks so it has a lot of slip.

asauer · 11-13-2007, 04:53 PM

Also, did you back up to the forklift, then get out and lock your hubs and immediately try taking off? Alot of times it takes a few revolutions of the tire for the hubs to lock in. I usually lock them in with 6 feet or so to spare so I'm sure they lock.
You wouldn't want a limited slip in your truck if you drive it on the road in 4WD...unless you don't mind not being able to turn.

Phillipmc1268 · 11-13-2007, 05:34 PM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: asauer</div><div class="ubbcode-body"> Alot of times it takes a few revolutions of the tire for the hubs to lock in. I usually lock them in with 6 feet or so to spare so I'm sure they lock.
You wouldn't want a limited slip in your truck if you drive it on the road in 4WD...unless you don't mind not being able to turn. </div></div>

Ditto that.

Just to be clear, there is NOTHING that can slip and not allow the front tires to spin. Quiet a few things to snap though [img]/forums/images/%%GRAEMLIN_URL%%/shocked.gif[/img]

91diesel · 11-13-2007, 07:02 PM

Yeah i know i wouldnt want the LS but was just confused why the front wasnt turning. That it probably why. I had the whole truck up in air when i tested and that could be why they turned then. I had NOT let them turn ANY when i was tugging on him. Just backed up, locked hubs and put it in 4wd. That would also explain why later after driving away, it felt like it was locked in and 4wd working.

I didnt even think about it taking some time to line up before it locks.

Thanks!

Mr_Roboto · 11-13-2007, 08:50 PM

You can steer with a LS up front, just not a locker. I have a 77 that has the LS front and rear from the factory. Granted ANY part time 4wd isn't going to steer easily with the front axle engaged, but that is from the front and rear axles binding.

1991F250 · 11-13-2007, 10:01 PM

I thought all the Dana fronts were LS??

asauer · 11-14-2007, 12:38 AM

Sign_Man, I know fully well that there is nothing that can 'slip.' I was stating that it can take a little forward or reverse movement of the vehicle to engage the hubs at times. I usually like to do this to ensure that they are fully engaged before I tug on something, thereby putting alot of stress on the hub before the splines are fully seated. Are you picking up what I'm putting down?
Yes, you can steer with a limited slip better than a locker, but it's still not fun. You're right- 4WD already tends to 'push' you past your objective when turning, and the problem is aggrevated by a limited slip when you're turning under power.
99% of trucks are open-differential front axles, thereby are (and will) only '3-wheel peel'

Phillipmc1268 · 11-14-2007, 10:24 AM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: anthony2010</div><div class="ubbcode-body">... or and locks so it has a lot of slip. </div></div>

Asauer, I wasn't directing that comment to you.

Sometimes I just do things now and don't remember why, like lock the hubs when I first turn off pavement. After dusting off the cobwebs in my mind, I remembered. When I was a kid my father and I were in our '68 Bronco going to deer camp on a muddy trail of a road that was passable in 2wd. We came to what appeared to be a puddle on the right side that turned out to be a rather large hole full of mud with water on top. Scooped out muck in near freezing weather to lock the hub in and after that, the damn thing still wouldn't move because the tire couldn't turn. Had to walk a mile wet and cold over that one.

At the same deer camp a couple years later an old man had a '78 F-150 4wd. He drove in the woods for the morning hunt and while we were down there it rained. He already had his truck in 4wd but for some reason the front wasn't pulling. The whole property was just ridges and hollows. The only ace we had was a PTO winch. We must have made 12 pulls that would have left an electric a smoking wreck in the rain to get him out that day. Cause of failure was enough moisture inside the hubs to cause them to freeze!

asauer · 11-14-2007, 01:27 PM

Ah, sorry about that. Moisture in the hubs? That's no good haha. Just one more reason why my truck never plays in mud...it's hard on stuff. I only take mine to play in the snow; it seems to be much more forgiving on things.