transfer case

[JayCDALivin]

Hey everyone,
Very sorry if this has been a topic already or already addressed, I searched the forum but found nothing. They other day my pathy was on the freeway I lost power real quick and pulled off the freeway and I just came to a stop in a parking lot. It was stuck and wouldn't move. The engine starts up and is fine. I can shift my transmission into all of the gears. None of which allow the vehicle to move. So i switched it to 4hi and tried and nothing but as soon as I put it in 4 low it moves. Now, my tranny seems fine as it shifts with no issues, I have good transmission fluid in right now. My question being is my transfer case stuck for good? Is it locked up? If so can I get it unlocked or do I need a new transfer case?

[PathyAndTheJets]

Manual or automatic? By lost power, did the engine bog down or did it Rev up but didn't speed up the vehicle.

 

My first thought is it's the clutch if it's a manual. 4lo might be multiplying a slipping clutches torque enough to get moving.

 

You should still be able to push the stick out of 4low, unless you drove it home like that. You might need to Jack up the wheels to let the drive line unwind in that case.

[Slartibartfast]

^Good question on how it lost power--that could tell us a lot.

Assuming it bogged down... it could be torque bind, but only if you were driving in 4H on the highway or it somehow popped in or failed to disengage from the last time you used it. You might try jacking up a front wheel to see if the wheel turns a little as it loses contact with the ground, try to turn by hand to see if the hub is locked, then try driving it again to see if that changed anything. I have heard of the transfer case chain breaking and getting jammed between one of the sprockets and the case, but IIRC that leads to it completely locking the output against the case, and I don't think that failure would've made it to the parking lot.

Unless it swerved when it lost power we can probably rule out anything in the front end. You might have a look at your rear brakes to be sure they're not locked. I would also check the fluid in the transfer case and the rear end if you can on the off chance one of them ran empty and burned up. I remember someone on here who accidentally ran his dry and burned it up.

[Terranovation]

I have a question, is the transfer case connected to the transmission in anyway because I noticed a small leak on my transfer case seal and I never changed my transfer case fluid at all. So should I change it? Fluid looks red and not brown or burnt looking.

[Slartibartfast]

Bolted together but they don't share fluids. Changing the tcase fluid in my '95 solved the issue it had where it would stick in 4x. I did the fluid on my '93 when I got it just to get ahead of it. It's a little tricky getting fluid to the fill plug, but not too bad if you've got a transfer pump or if you can rig up a bottle, some tubing, and compressed air to push the fluid up into the case.

[Terranovation]

That's good to know, I don't use the 4wd gears that much anyway. I will drain whatever is in there, degrease it then put some sealant on the seam then refill it. Luckily I have one of those bottles with a plastic tube as part of the lid. You pull the top up and the tube unravels from inside the bottle. I will probably get one of those hand pumps though for the bigger gallon containers.

[JayCDALivin]

Manual or automatic? By lost power, did the engine bog down or did it Rev up but didn't speed up the vehicle.

 

My first thought is it's the clutch if it's a manual. 4lo might be multiplying a slipping clutches torque enough to get moving.

 

You should still be able to push the stick out of 4low, unless you drove it home like that. You might need to Jack up the wheels to let the drive line unwind in that case.

Hey thanks for the replies I've been so busy between work old dog issues and just life right? Anyway heres the scoop when I was on the freeway it was like a moment of lost power back to normal back to loss of power and then I limped into a parking lot and she wouldn't move. My transmission shifts fine but the truck wont drive unless it's in 4L. I can go reverse and forward no issues in 4L. When I'm in 4H and 2wd it wont move. Is my transfer case boned? I've tried unplugging the battery to see if it was just a ecu issue and it didn't do anything.

[JayCDALivin]

automatic sorry

[JayCDALivin]

You should still be able to push the stick out of 4low, unless you drove it home like that. You might need to Jack up the wheels to let the drive line unwind.

If I jack it up how do I let the driveline unwind?

I didn't drive it home I called for a tow truck, didn't want to destroy anything else

[Cuong Nguyen]

Are you positive your fluid topped off?

[PathyAndTheJets]

Let me start by explaining drive line wind up.

 

When you go around a corner, your wheels turn at different speeds, as they travel in separate arcs, which is why automobiles have differentials. In 2wd, the front wheels are free to roll as they please.

 

But when you drop it into 4x4, a gear is engaged and the front driveshaft now receives 50% of the available torque, the other half of transferred to the rear wheels. The driveshafts can only spin at the same speed as they are effectively locked together.

 

So, when you turn, the front wheels take a wider arc than the rear, therefore they have to travel at a different speed. With the drive shafts locked together, the wheels cannot rotate at different speeds.

 

Then the drive train components act like a torsion spring, storing energy until the force exceeds the traction of the tires, and it "crow hops" or a component fails.

 

That torsional force can make it extremely difficult to take the transfer case out of gear, as the engagement sleeve is being forced against the gear teeth.

 

If you Jack up the wheels, the torsional force is released, and the lever should move as normal.

[PathyAndTheJets]

Make sure it's full of transmission fluid. Check while running in park.

 

Not super familiar with the Pathfinder autos, but if it's a cable actuated throttle valve I'd make sure it's not binding, and that it's adjusted.

 

Did the loss of power feel like it went into neutral, or it was slipping? Or was it bogging?

 

It sounds much more like a transmission or engine issue. It's hard to screw up a transfer case. Assuming it has fluid.

Edited March 15, 2016 by PathyAndTheJets

[Slartibartfast]

+1 on the loss of power question, slipping or bogging? Very important to nailing this down.

 

When you gas it in high range, when it doesn't move, does it rev freely like it's in neutral or does it act like it's under load?

 

And yet another question to see if my pet theory has legs... if you start the engine with the transfer in 2H or 4H, let it sit for a minute, and then go for 4LO, can you make the shift or does it grind like you had it in neutral for too long?