Three wheel drive in 4L?

[snacks]

So I was out on some forest roads around my house today. It was a little rainy, and while I got by with 4H most of the time, the three or four times I needed the 4L gearing, I got this sound from the passenger front hub like the hub was slipping in and out of lock or that something wasn't catching and meshing like it should be. Due to this, I only ran it in very short bursts, only when I absolutely HAD to. Also, when I initially put in into 4WD, the dash light didn't come on.

I'm a bit of a rookie when it comes to axles, hubs and the inner workings of gearing, so bear with me. Are the hubs shot? They're the stock Aisin hubs. Should they last forever? Like I said, I'm a rookie. I'd really prefer to not have to drop the $550 for new hubs, so it'd be a godsend if it's not that.

Another thing that I noticed was that when I locked the hubs, the driver's side hub felt like it was a positive engagement. The passenger's side just kind of felt weak and went to lock. I checked a couple of times on the trails and noticed that they both stayed in the "lock" position, even after a stint in 4L.

The thing that I don't get is that it only made the noise in 4L. 4H worked perfectly with power to the wheel and no grinding/catching. That's what's really got me stumped.

Any ideas on what could be the culprit? I don't totally disqualify user error, but I thought that I had my bases covered.

 

[2mbb]

The passenger side hub could be shot or it could just be sticking. Some times when the grease gets old it sticks in the unlocked position. You can do a test whether your hubs are engaging properly by crawling under the truck and trying to turn the front drive shaft by hand. With the truck in 2WD and the front hubs unlocked, you should be able to turn the front drive shaft by hand. With the hubs locked, you should not be able to turn the front drive shaft.

It could also be that your truck was not getting into 4wd all the way. You can also check this. With the front hubs unlocked, the transmission in 1st and the transfer case in 2wd, you should be able to turn the front drive shaft. When you put the transfer case in 4wd, you should not be able to turn the front drive shaft. If you can still turn the front drive shaft with the transfer in 4wd, then your transfer linkage may need adjustment. The transfer linkage connects to a shaft that comes out of the front of the transfer case. You can push/pull this shaft to see if you can manually shift into 4wd. Then check the front drive shaft to see if it doesn't turns (which means you're in 4wd).

Good luck.

 

[FinHJ60]

If it is the hub, it might not be completely shot, just the spring detached. Loosen the 6 bolts and check.

 

[CardinalFJ60]

also check y'er motor mounts

since it doesn't sound like you got that noise under regular 4H, but only on higher torquing 4L....you might want to check your motor mounts. under those conditions I've seen/heard this scenario and that's the culprit.
there are several threads about it: here's one.

Also, is it popping out of gear or just making noise?

https://forum.ih8mud.com/60-series-wagons/211442-grinding-sound-uphills.html




HTH

 

[cruiser88]

The hub is either dirty or has wayyyyy to much grease....or lack of spring tension. Aisin hubs are resilient as hell.....tear it down and have a check. Also if you find nothing wrong(and it will be obvious) check the birf.

 

[BlueCruiser84]

I second motor mounts, unless you are positive it is coming out of the hub. The motor will torque and the fan will hit the shroud which makes a grinding sound.

Brian

 

[lovetoski]

I second motor mounts, unless you are positive it is coming out of the hub. The motor will torque and the fan will hit the shroud which makes a grinding sound.

Brian

And this grinding noise is much more pronounced in L (higher torque). Its the DS mount that goes.

 

[snacks]

!!! Update !!!

Thanks for the responses!

This morning, I made sure that the transfer case was working by testing the drive shaft with it in 2wd (spinning), 2wd with hubs locked (maybe 1/2" of spin) and 4wd with hubs locked (no spin).

Then I moved on to the hubs. Took the top off and got rid of the ancient grease in there. Completely tore down the tops, reassembled and put some new grease in there.

I locked the hubs, got back in the cab and put it in 4wd. The light came on and everything! Threw it in 4L and the grinding was gone. Ran inside real quick (shut down the engine) and was back out in 5 minutes. Started it up again and NO 4WD LIGHT!!??

Got under and tested the drive shaft and it felt fine. Got out, ran the hubs from free to lock a time or two and it sounded like everything was working. Back in the cab and still no light? From what I can tell, it is operating in 4wd, but during the 15 minute drive I took to make sure that everything was operating correctly, that damn light never came on. So, instead of risking getting stuck (after all the rains of the past 2 days it's a bit muddy) with only 2wd to bail me out, I came back to the house.

I got in the barn and took the original offending hub off and it looked fine, but the grease was discolored again. Cleaned the grimy crap out, put a bit of new in and gave it another shot. Ran the driveshaft test and everything checks out.

So I guess it's working, with the exception of the light. I'd like to do a complete teardown and rebuild of the main hub, but I can't get those little cones out off the bolts. Any suggestions?

All in all, thanks a million.

Oh, I also checked the fan to make sure it wasn't a motor mount, and thankfully, it's looking fine.

 

[2mbb]

Thanks for the responses!

This morning, I made sure that the transfer case was working by testing the drive shaft with it in 2wd (spinning), 2wd with hubs locked (maybe 1/2" of spin) and 4wd with hubs locked (no spin).

To test whether it is in 4wd by hand spinning the front drive shaft, you need to have the front hubs unlocked, the transmission in a gear and the transfer case in 4wd. If you can not spin the front drive shaft then you are in 4wd. If the hubs are locked, you can't tell whether you are actually in 4wd, because the hubs are keeping the drive shaft from moving.

The 4wd light has nothing to do with whether the hubs are locked are not. There is a switch that monitors the position of the shaft that comes out the front of the transfer case. If the shaft is fully in the 4wd position and the switch is working, then the light should come on. When you think you are in 4wd but the light doesn't come on, from under the truck see if you can move the shaft anymore to get the light to come on.

If the grease is getting oily, then you probably have a bad axle seal and oil from the differential is getting into the front hub area.

 

[snacks]

OK. Transfer in 4H, 1st gear, hubs free. There's about 1/4" of twist in both directions. I consider that the 4wd is engaged. Am I wrong here?

I turned the cruiser on, locked the hubs and jimmied with the drive shaft, but the night never came on. Faulty switch? Is there a fuse for it somewhere? I don't NEED the light to work, it's more of a idiot-proof failsafe. I need all the redundancy I can get.

 

[2mbb]

OK. Transfer in 4H, 1st gear, hubs free. There's about 1/4" of twist in both directions. I consider that the 4wd is engaged. Am I wrong here?

yes. That is correct.

The 4wd light uses the same fuse as your other indicator lights such as brake, oil, high beams. However, the 4wd light is not "checked" when the ignition switch is turned on. However, if your brake light works, then it's not the fuse.

The switch is located on the right (passenger side of the transfer case near where the shifting shaft goes into the front of the transfer case (blue circle). It will be easy to find because it has wires going to it. The shifting shaft (circled in red) is what you should be moving to see if the light goes on. Pull the shaft out of the transfer case (pulling it towards the front of the truck) will engage 4wd. Pushing the shaft into the transfer case will put the truck in 2wd.