4WD Not Working - What did I screw up? (1 Viewer)

[Perovich]

1987 FJ60, stock transmission and transfer case.

Long story short my 4WD decided not to work today. And we're anticipating pretty good snowfall this week. I've removed and inspected the hubs per the instructions here. Everything lines up, and nothing appears to be incorrectly installed or damaged.

Rebuilding Aisin locking hub Locking hub rebuild

Here we go.... This is an IFS locking hub off my 89 4Runner. 86-95 will be the same. Solid axle 79-85 and many Cruiser hubs are the exact same design, only different sizes, but you probably could not tell from the pictures other than the different spline count. Notes: I have no idea what these...

forum.ih8mud.com

1.) With the transfer case in 4WD HI / LO, transmission in gear, and hubs in the "Free" position, the front drive shaft does not rotate.
2.) With the transfer case in 2WD HI and hubs in the "Free" position, the front drive shaft rotates freely.
3.) With the transfer case in 2WD HI and hubs in the "Lock" position, the front drive shaft rotates freely.

To me, this indicates the hubs STILL aren't locking / seating correctly. So just as a proof of concept, I took the gears off the dials and manually inserted them into the hub body to engage the splines of the axle. With both gears engaging the splines of the axle, I can still freely turn the front drive shaft. See video:


Additionally, with both of those gears engaging the splines of the axle, I can move either wheel forward or backward independently or together, without the front drive shaft rotating.

What am I missing?

 

[cps432]

If the hubs are in the free position when you have 4wd engaged the differential will not engage the axles. Lock the hubs and put it in 4wd. Put the transmission in neutral and then see if the front axle rotates as one unit with the drive shaft.

 

[Perovich]

So with the transfer case in 4WD, transmission in Neutral, and both front hubs in the "Lock" position, I can rotate the front driveshaft with no rotation from either wheel. Blocking one wheel didn't change anything, either.

Just to ease my mind, I pulled the drain plug and inspected the gears - all the teeth appear to be in tact. However, when I accidentally shoved the borescope up there, it appears that the axle shaft may have stripped inner splines? Excuse the nomenclature - by "outer shaft", I think I'm more referring to the carrier within the differential - it doesn't appear to be engaged by the axle shaft?

 

[3_puppies]

with the locking hubs removed, transfer in 4wd, trans in neutral, have someone look and see if the axle stubs are spinning
if yes, the issue is the locking hubs
if no the issue is deeper, broken birf, broken axle, front diff

just re-read the last post, you'll need to pull both axles and drop the front diff out

 

[ToyotaMatt]

So with the transfer case in 4WD, transmission in Neutral, and both front hubs in the "Lock" position, I can rotate the front driveshaft with no rotation from either wheel. Blocking one wheel didn't change anything, either.

Just to ease my mind, I pulled the drain plug and inspected the gears - all the teeth appear to be in tact. However, when I accidentally shoved the borescope up there, it appears that the axle shaft may have stripped inner splines? Excuse the nomenclature - by "outer shaft", I think I'm more referring to the carrier within the differential - it doesn't appear to be engaged by the axle shaft?

maybe you did not install NEW #7 Mark Head Yellow ZINC Gold Plated HUB DIAL Bolts correctly ?



ASCO & AISIN HIBS HUB Dials DIAL #7 Gold Zinc Bolts kit qty x 12 pcs for 1 complete front axle FJ40 FJ60 FJ55 FJ62 - VintageTEqParts.com - https://vintageteqparts.com/collections/everything-else-hardware-fsms-shop-manuals-special-teq-stuff/products/copy-of-asco-aisin-hibs-hub-dials-dial-7-gold-zinc-bolts-kit-qty-x-12-pcs-for-1-complete-front-axle-fj40-fj60-fj55

​

 

[g-man]

Go here: FSM - 1984 - 1990 Repair Manual, Chassis/Body - https://forum.ih8mud.com/resources/1984-1990-repair-manual-chassis-body.1/ in the resources section and download the chassis and body FSM. follow the instructions to remove the front drive shaft and companion flange. If the splines are bad on the pinion shaft, go to the RA (rear axle) section to see how to remove that.

 

[cps432]

The bore scope isn’t giving much info because I think you’re seeing the smooth case rather than the side gears in that shot. You need to double check that your knuckles are installed correctly and that the axle shafts are indeed inserted into the side gears in the differential. Sometimes when installing the long side it’s difficult to get the axle to seat in the side gear. It will not engage the differential if that happens, but you also can’t get the knuckle and hub assembly together if the axle isn’t seated all the way. Either way, you’ll need to dig deeper.

 

[g-man]

The bore scope isn’t giving much info because I think you’re seeing the smooth case rather than the side gears in that shot. You need to double check that your knuckles are installed correctly and that the axle shafts are indeed inserted into the side gears in the differential. Sometimes when installing the long side it’s difficult to get the axle to seat in the side gear. It will not engage the differential if that happens, but you also can’t get the knuckle and hub assembly together if the axle isn’t seated all the way. Either way, you’ll need to dig deeper.

But his pinion shaft is turning when he moves the wheels so the axles are snapped into the diff. At this point the OP should pull the diff cover for a better look. Most likely going to need to remove the diff at this point. Let us know what is going on in there.

 

[OSS]

I don’t think anything is wrong.
Everything is behaving correctly.

Got to remember that the front differential is open and when wheels are locked in their hub they’re supposed to rotate independently from each other.

The correct way to check if things are right is to rotate THE FRONT DRIVESHAFT when both front wheels are locked in their hub.
When you do that, one (or maybe both) of the front wheels will spin.

 

[2mbb]

I don’t think anything is wrong.
Everything is behaving correctly.

Got to remember that the front differential is open and when wheels are locked in their hub they’re supposed to rotate independently from each other.

The correct way to check if things are right is to rotate THE FRONT DRIVESHAFT when both front wheels are locked in their hub.
When you do that, one (or maybe both) of the front wheels will spin.

I've only done this type of testing with the wheels on the ground and turning the front driveshaft. With wheels on the ground in 2WD with both hubs locked the front drive shaft should not turn.

 

[g-man]

I don’t think anything is wrong.
Everything is behaving correctly.

Got to remember that the front differential is open and when wheels are locked in their hub they’re supposed to rotate independently from each other.

The correct way to check if things are right is to rotate THE FRONT DRIVESHAFT when both front wheels are locked in their hub.
When you do that, one (or maybe both) of the front wheels will spin.

But he's turning his wheels and something is turning inside the diff per his scope. So doesn't that mean the hubs are locked to the axles, the axles are turning, and the inner axle splines are snapped into the diff? And in that case shouldn't the front drive shaft/companion flange that is splined to the pinion shaft also turn with it?

I mean there is no disconnect in the diff. Only at the hubs and inside the transfer case right?

 

[2mbb]

After watching this video, I think that with the OP's set up, if he is turning one wheel with both hubs locked, one or both of the other wheel or driveshaft would have to be turning.

 

[3_puppies]

At this point the OP should pull the diff cover for a better look.

front axle doesn't have a bolt on diff cover
OP would need to pull the inner axles and then the diff