Hello All,

First thread for a new member here. Thank you in advance for your patience.

My 1997 F350 7.3 4x4 with auto locking hubs not engaging when in 4 wheel drive.
Driveshaft is turning. Driver side Axle turning. Passenger side Axle not turning.
I will be changing Hubs to Manual type but sounds like a problem in my Differential.

Any thoughts?

 

I've got some curious questions, because what you are describing is not clear to me. I think we need more specifics on your test procedure.

How are you checking that the shafts are rotating? All 4 wheels on ground? All 4 wheels in air? Hubs engaged (or at least commanded to), or open? Transfer case engaged (4wd) or not (2wd or neutral)?

If you're on the ground, hubs NOT commanded to engage, but transfer case in neutral or 2wd, then:
--Front driveshaft should be able to be spun by hand
--When spinning front driveshaft, one or both axleshafts should turn. If one side is relatively "stickier" than the other, one axleshaft might not rotate and the other rotates twice as fast as usual, since the side and spider gears inside the differential will spin, instead of driving the "stickier" axleshaft. Either way, this would be normal differential action... basically the same one wheel on wet ice and the other (the "sticky" one) on solid ground. The "stickiness" may be something like bearing pre-load, gunk on the axleshaft, or a hub stuck partially engaged.

If you're on the ground, hubs commanded to engage, but transfer case in neutral or 2wd, then I would suspect that one hub is engaged and one is not. If both hubs were engaged, you shouldn't be able to spin the driveshaft by hand. But if one hub is not engaged, you can still spin the driveshaft. The engaged hub won't rotate, so the driveshaft rotation is taken up by the side and spider gears transferring rotation to the axleshaft with the unlocked hub. Again, this is correct differential action.

If you're doing this with both front wheels off the ground, hubs engaged, with transfer case in 2wd or neutral, you'll have to watch the wheels spin or not when you turn the front driveshaft. And you may need to restrain each wheel in turn to see what goes on.

If I were forced to place a bet, it would be that one hub is either stuck engaged when the other is properly open, or one won't engage when the other is properly engaged. The odds of something like a broken axleshaft or stripped side-gear splines are much lower. And if the side and spider gears are messed up, things should be very noisy or not turn at all. But you'll want to do your diagnostics, carefully and completely, to rule that out. You may already have done the diagnostics and just not fully explained it in your post.

Hope this helps.

 

Sounds like the problem is the front hubs. Paddler has given you a couple ways to narrow down the source of your problem. The factory auto hubs must be maintained to function correctly. Most people switch to manual hubs for convenience.
The Dana 60 is pretty robust and should make some groanings if it is damaged. I surmise that the new hubs will get you going again.

 

Thank you both for your responce.

My visual test was vehicle on the ground with 4 wheel drive engaged.
I drove forward slowly and confirmed the front driveshaft is rotating.
The drivers side axle is rotating but the passenger side was not.
I also drove in 4 wheel mode, soft sand, and only the rear wheels spin.
I do not hear any noise form diff. or hubs so hopefully nothing like broke gears.
The function of the diff. was unclear to me as my understanding was both axles would turn when in 4 wheel drive mode. If not, a locker may help.
I do think the Hubs did not engage.

I love this truck. Many upgrades including- Larger turbo, 3" intakes, intercooler, heavier valve springs, 300% over injectors, 4" downpipe, tuner, upgraded E4OD trans & torque converter, custom Atlas Springs, crossover steering.

​​​​​​​Thank you again for your time.
Sounds like I need to do the testing you have suggested.

 

The front driveshaft is turning under power and only one axle is turning then the hub on that side isn't engaging. The front axle has an open differential which will spin the side that has the least resistance, which would be the side that the hub is unlocked.

 

Thank you all for your comments.

I did a test, as suggested, in earlier response.
With vehicle in park, and in 2 wheel drive, I can rotate the front driveshaft clockwise & counterclockwise, drivers side axle turns clockwise & counterclockwise, passenger axle turns small amount.
No noise or grinding in diff. or hubs.
Based on the comments, (enlightenment), my understanding is the diff. is operating normally (open diff.) and the problem is the "auto hubs" not engaging when in 4 wheel drive.
I will upgrade to Manual Hubs.
As for the diff., maybe a locker is the way to go to help in the soft sand. The Toyhauler I pull is a heavy beast, and some of the camping spots are in softer terrain.

 

Good that you did the diagnostics to isolate the issue. I realize now that I had assumed open diffs; lockers or limited slips would react differently. If you don't know what's broke, you can't fix it... but you can still spend a lot on parts and labor trying.

I have ARB air select lockers front and rear in mine. Got stuck once on flat, hard-packed glazed ice; one wheel on each axle spun. I decided that was not fun. With the ARBs, I can command full lock, or full open. No worry about hopping or ratcheting in corners in daily driving, or limited slip clutches wearing out. But you do have onboard air, air seals in the diffs, and vent lines to worry about. Engaging an ARB with a blocked vent line may blow your axle seals, found that out the hard way. A conventional locker in the front may not be an issue for normal driving, unless you are in the habit of locking manual hubs and leaving transfer case in neutral until things get messy. Detroit TrueTrac looks like an interesting option in place of limited slip.

One time I was very happy for air lockers front and rear... yielded the 1.5 lane gravel road to a tri-axle dumptruck, and put the passenger side in the ditch. Passenger hub was down in the gunk, so only locked driver side hub. 4 low, both diffs locked, crawled right out. If I did the diffs now, I would be tempted to go with an electric locker, and TrueTrac if e-locker is not available. I would not go with a conventional locker in the rear, but many folks do.

The short version is that there are quite a few options out there; do some research and select what makes sense for your uses. To see some soft sand issues and recoveries, you may want to take a look at Matt's Offroad Recovery on YouTube.

 

I have a Lock Right locker in the front and a Detroit locker in the rear both work great for daily driving and offroad, they are all mechanical and don't require air, cables or wires to operate. The Lock Right is a lunchbox locker that is easy to install because it goes into your existing carrier, Spartan and Aussie lockers are good also and work the same way.

 

Thank you "paddler and 00t444e" for you help. Your advise was very helpful.