4WD won't engage front wheels '77 FJ40

[DocHawkeye]

I've been lurking around this forum for a hot second now and you all have been an imense source of help with trying to fix up the 1977 FJ40 I've inherited. So, I'd like to first off thank everyone who contributes to this forum.

A little piece about my 40: as stated, it's a 1977 FJ40 that has (I believe) American racing wheels and a set of 32" Coopers (except the spare that's still the snow cruiser that came with it). Very early on in it's life, the 2F was swapped out for a Chevy 305 out of an El Camino with a 450 economaster and an Edelbrock intake. Everything else (save for the beetle washer reservoir and battery placement) is stock to my knowledge/experience. There's a laundry list of things that need to get fixed, refurbished and changed on this truck, but with winter around the corner, I want my FJ to be in good shape to wheel during it's first snowy winter since the 80s.

Currently, 4WD on the transfer case will not engage the front wheels. Spinning the rear wheels with the transfer case engaged spins the front drive shaft, and appears to spin at least the driver side axle (checking through the dif level check). Spinning the front drive shaft doesn't appear to spin the spline in the hub lock in either hub. Needless to say, engaging both hubs and spinning either wheel does not spin either the opposite wheel nor the drive shaft.

What I'm really looking for is guesstimating before I tear the hubs apart. Im not usually a big fan of throwing parts at a problem until it gets fixed. I want to figure out what's failed, and why. However, if I were to guess at this point, I'd lean towards a failed hub/birfield axle. My understanding is that the Warns in this era were not the best on these little trucks.

And, of course, just a few pics while it's in the air, I'll grab some more before I call it quits tonight.

 

[rkymtnflyfisher]

Put all 4 wheels on the ground and try.

 

[rkymtnflyfisher]

And welcome to mud, that was a well written, detailed description of your rig and the issues you're having, we'll done.

 

[DocHawkeye]

All four wheels on the ground, in 4Hi, front shaft won't spin.

All four wheels on the ground, 2Hi, front shaft spins freely.

My understanding is that both cases, the drive shaft shouldn't be spinning, but if nothing else localizes it to the front end.

And welcome to mud, that was a well written, detailed description of your rig and the issues you're having, we'll done.

Much appreciated, might hope so being a mechanic by trade lol.

More pictures of my Patina'd FJ attached.

 

[charliemeyer007]

It could be a lots of things wrong in there, taking the hubs apart is easy enough. Brand new Warns are like $300 for the set. Hubs might just be stuck with dried grease and cleaning could solve the issue. Could also be spines, joints, broken shaft(s). My 72 had Warns put on in 1980 by the PO, been there ever since - never caused me an issues since I got the rig in 82.

 

[duncanrm]

.

 

[DocHawkeye]

It could be a lots of things wrong in there, taking the hubs apart is easy enough. Brand new Warns are like $300 for the set. Hubs might just be stuck with dried grease and cleaning could solve the issue. Could also be spines, joints, broken shaft(s). My 72 had Warns put on in 1980 by the PO, been there ever since - never caused me an issues since I got the rig in 82.

Well driver hub off, and the picture attached is what we're looking at. I know how the passenger side looks and it isn't pretty, and I'm honestly anticipating having to replace it because I know that one is seized to be engaged.

But as for the driver side, definitely some old grease, but spinning the spline doesn't spin the drive shaft with it without 4wd engaged.

I was following another thread on this trail from a bit back and someone was saying that the Aisin hubs are a bit of an upgrade from the Warn ones.

In the mean time I'll see if I can get the passenger side free and at least work on trying to refurbish it. Wish my luck lol.

 

[Malleus]

Replace the hubs with drive flanges. You don't need them; they're axle jewelry.

Are you expecting to turn the propeller shaft (from the transfer case) with the driveshaft? Have you tried turning the propeller shaft and verifying the driveshafts (at the wheel) do not turn (now that you have the hubs off)?

Which shaft are you referring to in post #4? The propeller shaft (from the transfer case) or the driveshaft (inside the axle)?

You may have more than one problem; the slip ring in the transfer case may be engaging in one gear but not the other.

If the transfer case is turning the propeller shaft, and the driveshafts are not turning, you have a differential problem. If only one driveshaft is turning, you definitely have a differential problem.

 

[DocHawkeye]

Replace the hubs with drive flanges. You don't need them; they're axle jewelry.

Are you expecting to turn the propeller shaft (from the transfer case) with the driveshaft? Have you tried turning the propeller shaft and verifying the driveshafts (at the wheel) do not turn (now that you have the hubs off)?

Which shaft are you referring to in post #4? The propeller shaft (from the transfer case) or the driveshaft (inside the axle)?

You may have more than one problem; the slip ring in the transfer case may be engaging in one gear but not the other.

If the transfer case is turning the propeller shaft, and the driveshafts are not turning, you have a differential problem. If only one driveshaft is turning, you definitely have a differential problem.

This was my concern is that it would be a significant issue that would end up adding parts time, and most importantly $$$ to the fix.

However, I am pleased and also sorry to report that I am pretty sure that it was the passenger side hub not engaging. I'll throw a picture up of both hubs side by side, the passenger one has already been hit with a wire brush/parts washer and the driver side hasn't been dismantled, but it's biggest issue is just how old that grease is. I think I may have screwed myself over, but I couldn't get at the retaining bolt with how the lock was seized into the housing.

Thankfully both of the splines spin with the 40 in 4wd, but I'll get them cleaned up and put back together for the time being to ensure that with both operating properly, all four wheels engage.

 

[rkymtnflyfisher]

Well driver hub off, and the picture attached is what we're looking at. I know how the passenger side looks and it isn't pretty, and I'm honestly anticipating having to replace it because I know that one is seized to be engaged.

But as for the driver side, definitely some old grease, but spinning the spline doesn't spin the drive shaft with it without 4wd engaged.

I was following another thread on this trail from a bit back and someone was saying that the Aisin hubs are a bit of an upgrade from the Warn ones.

In the mean time I'll see if I can get the passenger side free and at least work on trying to refurbish it. Wish my luck lol.

View attachment 3471526

Drop those old crusty hubs in a bucket of so.e sort of degreaser and leave them alone over the weekend. I bet they'll clean up enough to work for years to come.

Rebuild the front knuckles while you're having so much fun!

 

[DocHawkeye]

Reporting back, sliding that passenger side back in spins both wheels. Thankfully I wont be needing to rebuild the T-case or anything else at this current point in time.

Drop those old crusty hubs in a bucket of so.e sort of degreaser and leave them alone over the weekend. I bet they'll clean up enough to work for years to come.

Rebuild the front knuckles while you're having so much fun!

Maybe I'll do a front end rebuild whenever I end up needing to tear the front end apart or I run out of other fun projects to do!

For the time being I'll probably get a gasket kit for the driver side and order another hub lock in for the passenger side. At the moment, the springs are still fubar'd, and I don't think I have the means to properly get them back on the cap's pins to make the assembly actuate properly. At least I can leave both engaged for a jic situation because it seems like the snow's gunna be coming in early this year. Appreciate everyone's guidance and theory crafting here. Hopefully the next thread I make wont be until next spring when I put it up on blocks to reseal the drive train, recoat the frame and sort out my wiring.

 

[Malleus]

Drive flanges are cheaper. Just sayin'...

 

[rkymtnflyfisher]

Drive flanges are cheaper. Just sayin'...

Help me understand the rationale behind using drive flanges??

Always locked, more rotating parts in the front end ultimately causing unnecessary wear and tear on the front axle and t-case, reduced fuel mileage, it’s just like driving a Dodge Ram.

Maybe I’m missing something here, but driving my Ram with no way to unlock the front and my 40 with it completely unlocked, I don’t understand the benefits of the drive flanges.

 

[charliemeyer007]

My 72 went the first like 68,000 miles with no hubs. The PO put on Warn's and drove it about 2 years and 2000 miles before selling it to me in 82 (thank you Jack). Maybe in the late 80 I redid the front end. There were groves cut in the axle flats from the oil seals. Yea some day I'll weld them up or find a Speedi Sleeve to fix that leak. Hubs are good to have IMHO.

 

[pb4ugo]

I've wheeled Warn hubs for decades and never had any problems. It's not like Warns are weak, it's that Aisins are stronger. The weak link are the birfields. I've broken a crap load of those.

Drive flanges will eventually where out parts.

 

[Living in the Past]

While parts are spinning they are not under load driving the front wheels. Can't see the wear shortening the life of parts anymore then on the rear axle which is always under load. Minor gas mileage saving with lockout hubs. Many markets used their cruisers a lot harder where most a work vehicle not an RV. I'm sure they help but not like the world's coming to an end of you don't lockout hubs. Carrying a set of drive plates as trail spares is not a bad idea. Never heard of a drive plate failing. Can't says the same about lockout hubs.

As for the seal on the inner axle Toyota has used a system that disengages one of the inner axles for years. Those the inner axles are always spinning as well as spider gears in the diff. Can't help but wonder if it has to do with less failures than lockout hubs.