Front differential Issues?

[eblank]

So here's my story:
I put the truck in 4 lo just for fun to drive over a coupe railroad ties. I put it back in 4 hi. and start to drive away. Then it starts making an awful binging kindof surging noise and feel. It kindof comes and goes but is always there when I turn and sometimes when going straight. Turns out that the bolts on the front end of the front prop shaft are digging into the exhaust pipe (not just the heat shield). So i prop up the front end and the wheels turn in opposite directions like they were under tension. and when i turn one (while in park) the other turns the opposite direction. after I let it down the prop shaft is no longer digging into the exhaust. So I drive it again in hi gear and it immediately starts to bind again...

So does anyone have any suggestions, ideas, or troubleshooting ideas? I'm all ears. I'm by no means an expert on the 4wd system so I'm wondering how the front wheels should act in park, hi, and lo gear when off the ground.

this is pretty major binding so I'm not leaving my driveway unless I take out the prop shaft, so need to get this figured out asap...

[Ldub]

Could be that the front axle brackets are loose on the axle or frame...

Put the front end up on jackstands under the frame, chock the rear wheels 1st, then see if there is any slop F-R in the frt axle assembly.

[Marlin]

I would agree with DUB, is the prop shaft tight? If that CV goes, that could be an issue as well. If it is rubbing the exhaust, are your exhaust hangars good? Perhaps the exhaust moved, not the driveline?

[eblank]

well I checked the axle brackets and everything appears to be pretty solid down there. The exhaust is only a few inches from the header so there's no play there at all. and the prop shaft bolts are tight too.

nothing seems to be loose down there but clearly the shaft is moving vertically. I'm thinking that possibly the entire diff is rotating about the axle shaft when under torsional stress, causing the back end and prop shaft to sit higher, but this is a guess. tomorrow I'm going to try to recreate the issue and watch what happens when the tires are lifted off the ground.

What I'm struggling with is, why is there all the tension and whats causing it? is it stuck partly in 4 lo or something?

[Ldub]

Did you put the trans in neutral, before shifting to 4-hi?...

[Triathlete]

In addition to what Dub said have you checked your motor and trans mounts?

[tom4bren]

Could be that the front axle brackets are loose on the axle or frame...

Put the front end up on jackstands under the frame, chock the rear wheels 1st, then see if there is any slop F-R in the frt axle assembly.

Don't just check where the axle housing bolts to the bracket (although that's the most common place they come loose). Also check where the brackets attach to the frame. They attach there using a rubber bushing to allow some 'give'. If that bushing has been damaged, it could allow the axle to move in relation to the exhaust.

Also, any time that you've had it in 4L, toss a little terra-firma in reverse once you have it back in TOD. It may not help ... but it don't hurt either. Blue haired 4 wheelers learnt to do that back in the day to ensure that the transfer case fully dis-engages.

[eblank]

So apparently its as simple as the 4wd staying engaged. I drive it around and, throwing it into and out of 4 lo, and it was really hard to get out of 4wd. It gets out of lo, but the 4wd would stay engaged until I went forward and backwards a few times. So this means I have 2 issues:

1: Its getting stuck in 4wd. Any suggestions for this?

2: My front diff is rotating under tension, allowing the back of it to go up. I jacked it up and looked around, and all the mounts appear to be tight. But I do have a question. Where the axle mounts mount to the frame there are rubber bushings on the front side. I'm wondering if this bushing is shot or if the bolt is not tight enough. Here is the one on the passenger side, the one on the driver side has more exposed thread, but it measures the same (2 in). This one looks like it could be tightened, but I couldn't get anywhere, and didn't want to get out a breaker bar until I knew if it is already tight.

[tom4bren]

The 2 issues could be related. If the front axle is rotating while in 4WD, I guess it could be putting the transfer case in a bind & not allow it to disengage. It's just a shot in the dark ... but possible.

I've not heard of those bushings going bad ... except during removal.

My first experience was when we were installing diff drops on a VX. The bolt was completely siezed inside the bushing. The bushing was completely destroyed by the time we got the bolt out.

My second experience was when somebody returned their diff brackets to me to be modified. One of the bushings was missing so I assumed the same thing happened.

The good news is that the bushings are available. I'll have to look up where I bought them from. IIRC they were about $10 each.

As far as how tight the bolts should be ... pretty friggin tight. I didn't look it up to see if there was a torque spec on those bolts but I just tightened them down as tight as I could. Schlep them down with penetrating oil real good before you start tightening them so that you aren't fighting against binding (just compression).

More bad news. If you do have to replace those bushings, you'll probably have to actually remove the bracket entirely. They don't exactly just slide in. You don't need a 2 ton press to get them in but you won't be able to push them in with just your fingers either.

If I were you, I'd just try tightening them up first. If the problem persists, then maybe look into replacing the bushings.

I've got a spare set of brackets sitting in my garage if you decide to go that route. I'd be happy to do a freebie swap with you.

BTW, have you changed your fluids lately. I'd make sure the transfer case & front diff have plenty of gear lube in them. Better yet, go ahead and drain them & replace with synthetic.

[Ldub]

BTW, have you changed your fluids lately. I'd make sure the transfer case & front diff have plenty of gear lube in them. Better yet, go ahead and drain them & replace with synthetic.

I think ATF would be a better choice for the transfer case.....

[tom4bren]

Sorry Doobster but last time I checked ATF was actually a type of gear lube. Even though your world revolves around correcting me ... no dice this time

[evillecutter]

eblank any progress with this issue? ive been having similar issues for some time now and im just about out of options other than paying out the wazoo to have someone who i dont know wrenching on my baby - and were the tod lights showing that you were in 4low when you tried to put it back in 4hi? mine shows tod working fine but i have binding - never in a straight line only while sharp turning - other than the axles and differential the only other thing i can think of is something maybe wrong with the power steering gearbox?...

[evillecutter]

eblank? hello.....?