4x4 Working Properly???

[Blue m&m]

Ive got a 94 sport 4x4 with manual locking hubs and a rear locker.

A few weeks ago, I got stuck in an epic mud hole and noticed the front wheels were not turning. It was suck so bad, I broke mounts on my suspension lift. This bracket has since been repaired. Since then, I’ve taken the following steps.

1. Confirmed manual hub operation. The front axels will not spin by hand when locked in the ground. They spin fine when unlocked.

2. Buttons, control module, and transfer case motor seem to be working fine. When it’s jacked up, it freely moves in and out of 4 high.

When it’s jacked up, I notice the following condition. The power does not go to the front diff in 2x4 (as it shouldn’t). Power transfers to the front diff in 4x4 (as it should). When in 4x4 all wheels spin freely at low rpm. If I stop either front wheel, the other keeps pulling. If I stop either rear wheel, all wheels stop.

Is it normal to have the front stop if the rear wheels are forced to stop? If not, am I looking at a problem with my transfer case, front diff, or something else all together? If it is normal, what is the best way to check to see if the front wheels are pulling under load?

 

[Blue m&m]

Anyone got any ideas here?

 

[Mbrooks420]

If the rear can’t turn the front won’t be able to. The axles are locked together 50/50. To test the front drive just remove the rear driveshaft and see if it will drive.

What kind of locker in their rear? (Not relevant to the problem, just curious)

 

[Blue m&m]

Good to know about the 50:50 split. With that in mind, stopping both front wheels should stop all four correct?

To really test it, should I drop the drive shaft entirely and see if it will pull around the yard?
I’m fearful that the front pulls with little resistance, but does not pull under load.

I’ve got a Detroit locker in back. I’ve been very happy with it. Without it, I would have never made it out of satans mud hole in 2x4.

 

[Mbrooks420]

Yes, blocking both fronts should stop all 4. There’s no clutches involved in your case, so if your hubs are working properly I can’t really see a reason or way it could slip.

Dropping the rear shaft would prove it, though.

 

[Blue m&m]

I’ll work on that and follow up. Thanks for the common sense tip

 

[Blue m&m]

Update. I dropped the rear driveshaft. Before lowering it down, I thought I would double check the system.

The transfer case sounds bad. Real bad. I’d describe it as a metal gravelly sound, almost like small gravel being turned in there. Best case scenario, I’d wager no fluid in the transfer case.

Without the rear driveshaft.... it spins fine in 2x4. If I attempt to drop it into 4x4 on the fly (about 30 mph on the speedo) it makes the gravelly noise and the front wheels won’t spin. If I put it in neutral and shift to 4x4 from a stop, it starts spinning the front wheels, and then quits and starts making the gravelly noise.

I suspect something with the transfer case. Am I looking at a full replacement, do I just need to swap out fluids, or something else all together? Is there a chance the magic tansfer case motor isn’t making it all the way to the 4 hi detent?

 

[Mbrooks420]

Spinning in 2wd with no driveshaft, and then actuating 4wd is a terrible idea. Typically when in 2wd the front is being driven at the same speed. It’s the same reason you don’t spin in a mud hole and just slap it in 4wd.

I’m guessing the problem is more than fluid.

Pull the shift motor. There are stops that deteriorate and can keep it from shifting into the proper place.

 

[Blue m&m]

I’ll check the shift motor. I’ve got a spare laying around. Might as well start with the easy stuff.

....and yes, I can confirm that shift on the fly 4x4 isn’t the best idea without a driveshaft.

 

[Blue m&m]

Changed the shift motor. Same problems. Sometimes it engages well. Most times it sounds like the chain is not engaged properly. Also, the transfer case won’t even pretend to go into four low.

Looks like I’m headed for a transfer case swap. Luckily my recently purchased donor vehicle is supposed to arrive next week.

 

[Blue m&m]

Just thought about it. I didn’t have my foot on the brake, so that might be the four low issue. Either way, four high ain’t healthy.