I have an issue with my truck. When driving down the hyway in 2Hi with the hubs unlocked, I can shift right in to 4hi with no grinding. This tells me that the front driveshaft and axle are turning at the same speed. I dont understand what is powering them.

If I reach under the truck and turn the driveshaft by hand, it turns free and I can see the universals turning at the wheels. If I tye rap the driveshaft to the radius arm, it doesnt brake the tyerap and there is less vibration at hyway speeds. Do you think the grease in the hubs could create enough drag to spin it up?

I just changed the tranfer case. (see noise thred) But my old transfer case did the same thing. Maybe this is a hi milage transfer case thing. I have manual hubs and a manual shift T-Case. I thought the whole idea of the 2hi and hubs was to save gas. How could it if all that stuff is spinning?

Could you guys that have a manual T-case try shifting in to 4hi at speed? I'm not asking you to yank it in to gear, just drive at a constant speed for about thirty seconds and slowly pull the shifter. At the first hint of grinding, push it forward again. Let me know.

 

No, I don't think I can do that, well I know that I can but I won't.

Read the directions that should be on your visor.

 

There's a spline at the end of the front axle shaft(s). Locking the hub locks the hub to the spline, this transfers the rotation of the front axle shaft to the wheel. This is where the burlesquing appelation would be applied to the operator.

 

Come on guys. Someone out there must have a manual shift T-Case. It only takes a few seconds to try this.

 

Doesn't take any seconds not to.

 

Wish I had a manual X-case but I have the electric 1356 in my 93. Regardless of how many seconds to do or not do it, I would try. I would still try, but I think the shift mechanism is prevented from operation by the PCM at any speed.

Just food for thought------but I am not surprised at some slight spinning of the shaft, just some oil would probably give enough "grip" to start a spin. All it takes is a tie wrap to overcome that friction and hold it still. I am sure you are aware, that there is not much mass to cause grinding because of almost no inertia in the slight spinning of the driveshaft and axle shafts. Also I dont know the design of the gears in the Xfer case or even if there is a synchronizer in them (AKA "blocking ring"). I would bet your next paycheck that if you try with the hubs engaged you will get lots of grinding.

My .02 is that you may not have a really big problem, except maybe for it jumping gear. I dont have a manual, but wonder if the shift shaft has detent groves in it that some spring-loaded ball bearing is used to hold a particular range. Maybe it is as simple as a broken spring in a detent----. Now we know that it probably isnt anything simple---no such luck!!

LOL

 

Here's a quote from the 1996 Bronco User's Manual,
"
To shift from 2H to 4H:
Stop the vehicle and move the transfer case shift
lever straight back to the 4H position, the
automatic locking hubs will engage when the
vehicle is driven. When the automatic locking
hubs are engaged, shifts between 2H and 4H
may take place at any speed."

The automatic locking hubs may disengage in
2H if the vehicle’s direction is momentarily
reversed, or the vehicle is allowed to roll
slightly in the opposite direction. If a
grinding noise occurs when shifting from 2H
to 4H while the vehicle is moving, one or
both of the automatic locking hubs have been
disengaged and the transfer case shift lever
should be switched back to the 2H position.
To shift back into 4H, stop the vehicle and
move the transfer case shift lever straight
back to the 4H position.

When the vehicle is stopped while in 4H and
the vehicle’s direction is reversed from the
previous direction, the automatic locking hubs
momentarily disengage and then re-engage.
The automatic locking hubs may click as they
automatically engage in the new direction.

 

What part of "Don't put truck in 4x4 mode without the hubs being locked" do you not understand?

 

gk50. Do you understand my first post? I can shift in with no grinding on two transfer cases with out the hubs locked. I want to find out if this is common. If you dont wish to try it, DONT.

Ben, The electric shift actualy will excellerate the front up to speed with a magnetic clutch and then lock. (I had one on my other Bronco.) I've got quite a funny story about my ex girlfriend and the electric shift. LOL But, let me assure you it will go in 4H at highway speeds.

The manual shift T-case has no magnetic clutch. Any of you have a manual shift that can pull a shifter gentily, please let me know how yours works.

 

I've been thinking about this "grinding" issue if you engage 4X4 while moving---Yea, thinking is dangerous, I know . Whether or not the hubs are locked, why would there be any grinding? Without being locked, the shafts obviously spin a little, and besides, there isnt much inertia in just the weight of the shafts, so there shouldnt be much grinding, certainly not like going from 2nd to 3rd on the tranny without using the clutch and without synchronizers.

If the hubs are locked they will behave like synchronizers and have the shafts spinning at the same speed as the Xfer case anyway (except that sometimes the front and rear gears are not exactly the same ratio). So why would there be any grinding ? All the meshing gears will be at the same speed. Let me be clear, just in case someone dosnt understand, (not talking about helirich either) I "aint" saying that there will be no grinding-----just asking what reason would cause grinding. Inquiring minds want to know---

People with welded spiders in the front frequently run with one or both hubs unlocked, particularly if there is some hard packed surface in the mix, such as the "spillway" in New Orleans, which we did. We bought a 72 bronco from a friend that had welded spiders in the front (D-44) and with the hubs locked, it will damn near rip your hands off if you arent VERY careful. Yes, some people have said that theirs did not, but this one would. What about that do you not understand?

The Mfg recommends against many things that are commonly done, lift kits for example----!

 

I think there is more inertia than you think. The shafts, ring gear and carrier are pretty heavy. I also think there should be more drag from the heavy oil in the diff.

But let me make this clear, after driving awhile I can slowly pull the shifter back and it kind of stops like it hits a detont, and if I pull a little harder, it justs snaps in. Zero grinding and the 4x4 light comes on. (go figure)

I have not tried it while excellerating. I would have to assume that the shafts couldnt get up to speed right away.

In any case, I'm looking for someone to brake their chain, just ease it back and stop if you hear it rub.

 

Your hubs might be locked while showing unlocked. rebuild your hubs to repair.

Don't' operate vehicle incorrectly.

 

Freudian Slip, "In any case, I'm looking for someone to brake their chain, ..."

Nuff Said.

 

What a great place this is, now we have psychiatrists offering analyzations of our statements------is there a charge for this service, or may we graciously accept this as a gift? Freudian slip? that must have something to do with Xfer case adjustment, because thats what this thread was about----. "Nuff said" is when someone answers his question

 

The owner's manual on my Bronco says i can engage 4wd while moving (wich i don't anyway)... then again, i have electric locking hubs (wich i will be taking out sooner or later).