What is that whine?

[shelby987]

I swapped my front axle about a year ago or so, the primary reason was an accident that left me without front brakes, so I upgraded to a corp 10bolt front with a locker. Today was the first actual day that I actually got the truck out on the road and had cause to use the 4wd.....while driving the truck very slowly out of the driveway, I heard a loud whine.....so I drove the truck to a nearby parking lot, I tried driving with one hub lock, then the other......but hubs seem to be easy to lock, but very difficult to unlock (even on flat ground, no load on the axle).....the noise didn't change with one, the other, or both hubs locked.

Could this noise be the hubs, the gears them selves, or is this just a normal noise to hear from a locked front end?

Also, my truck is a 250 with some upgrades.....pretty torquey, never had a problem in 2wd spinning the tires....but it seems to bog under the stress of 4wd, could this show that something is bound up, or is it just because the engine is under that much more load in 4wd?

[LONGHAIR]

Sounds like the gears are not the same ratio in the front as in the rear. This will cause a serious bind.

[shelby987]

I don't think that is it, both front and rear gears are 4.10's. I checked both before install.

[GMCMAX]

Tires all the same?
I had a tire go bad, so I put 2 new ones on the front, and the rears were about half worn; even that small amount of difference caused the drivelines to clank and I couldn't hardly get the t/case out of gear; just rolling and step on the clutch and it would stop itself quick.

[LONGHAIR]

I don't think that is it, both front and rear gears are 4.10's. I checked both before install

Ok, if that is the case, there are a few other things to check.
First being the gears themselves. Just because they are the right ratio, doesn't mean that they are "good". Also as GMCMAX said, the tire diameter will affect this. If the front tires are shorter, the rears "in effect" push the fronts. This makes the front gears run with the load on the coast side. THis may cause a noise and a bind.

You could have problems with the lock-out hubs too. They could make some noise but that shouldn't cause a bind.
You could have axle-joint problems too. That shouldn't cause a bind in the drivetrain, but it might in the steering.
Bad carrier bearings could make noise too, but again no bind.

What kind of locker?

[shelby987]

I was told that it was a detroit locker.
I forgot to mention, I get the same whine with one, or both hubs locked, and the truck in 2wd, so I think I can eliminate the tires from being the issue.
The axle had been rebuilt with new bearings, u-joints, and brakes when I bought it.

[LONGHAIR]

I was told that it was a detroit locker.
I forgot to mention, I get the same whine with one, or both hubs locked, and the truck in 2wd, so I think I can eliminate the tires from being the issue.
The axle had been rebuilt with new bearings, u-joints, and brakes when I bought it.

I hope it's not....unless you bought it specifically for that. Since it took you a year to use it, it doesn't sound like it. IMHO, a Detroit Locker is not the way to go on the street....in the rear, much less in the front. You will get "squirrely" and unpredictable steering. On ice/snow it will likely be worse than a stcok "open" differential.

A hub locked will force the gears to turn, so it could still be the whine. Not only are they turning but the turning force is coming from the axle, not the pinion..so again you are running on the coast side of the gears. This can definately cause the whine.

As far as the bind? ....not sure. Did it do any of this before you tried to put it 4wheel drive? Have you driven it at all since the front axle swap? If you totally unlock everything (hubs and transfercase) does it drive like it did before?

[shelby987]

If I totally unlock everything and put it in 2wd, the truck drives perfectly normally.....no noise, no bog, no problems.

I didn't buy it because of the locker, it was just an added benefit....typically I drive my car as a DD, if I do need the truck on the road in bad weather I rarely if ever actually need 4wd, so I wasn't really concerned with having a locker in the front.

I guess I will have to pull the hubs apart, and pull into the diff. itself to see if anything jumps out at me......if anyone has any ideas, let me know, otherwise I will post if I figure out what the problem was.

[Old Chevy Mech]

Jack it up very solid fire the engine up and run it. Listen with a mechanics stethascope <sp?> or use a screw driver to locate the source of the noise.

Frank

[GMCMAX]

I don't know, but if it is a locker and you only lock one hub, you are still turning the ring and pinion... maybe the pinion is set way too tight. With the hubs unlocked is the front drive line way too hard to turn by hand? That or maybe the front output bearing in the t/case...
Hope ya find out before having to tear everything down

[shelby987]

Way to hard to turn is a relative term when you have manual steering, but I would say no, it isn't harder to turn now than it was before the switch.....I would say the noise is definately coming from the axle, and not the t-case.....the noise seems to go to the side of the locked hub (if I only lock one)....it doesn't seem centralized like a t-case problem.

As a note....when 4wd is engaged, turning is DEFINATELY hard, I assummed this was a locker issue (problem with a locked front end in general that is).

[vtblazer]

I'd jack it up and start turning thing's manually, looking for the bind.

Could be the locker acting up IMO.

As mentioned earlier, a Detroit in the front of a daily driver is not a good thing.

Turning on a dry surface with the hubs locked in has the potential to break stuff, just be careful.

[GMCMAX]

Well, I wasn't really talking steering, but crawling under and trying to turn the driveshaft with the hubs unlocked to see if it is bound up........