Is it my xfer case clutch?

[cweagle]

Hi all,

I have a high-mileage 94 XLT with auto hubs. The prev. owner didn't use 4WD much, but he said it worked 'a while ago'. I've done a lot of front-end work on it (_carefully_ cleaned out hubs & replaced one, axle u-joints, ball joints, wheel bearings, spindle bearings, radius arm bushings), and over the winter break took it up to Maine (from Boston) and went out in the mud with a friend - first time. Had a @#$% blast, but I discovered that 4WD doesn't seem to work. As is usual with me, it's different than most posts here I think.

Push the button, and the xfer motor hums, and the 4WD light comes on. I can get it into 4LO too (more humming, the light, and the reduction is evident). But only my rear wheel(s) spin in the mud, ie, nothing going up front (unless the xfer case works differently than I thought it did!).

Did the first gens have a clutch to engage the front driveshaft, and does this have anything to do with the brown wire? Most brown wire posts I see are for 2nd gen, I think?

I have no fear of opening the xfer case and have a good junkyard here - I just need to know where to start. Is there a teardown/picture-fest for the BW1354? All I see is for the motor, which clearly works...

Oh, and last time I had a front corner up, I spun the front driveshaft by hand, and the wheel spun, so there's at least _something_ happening in the front diff.

Thanks!

 

[MrShorty]

As far a I know, there is no "clutch" in the 13-54 and the brown wire thing doesn't apply to the 13-54. Usually, if the problem isn't the t-case on these, then it's the hubs. Are both hubs locking in (remember you have an open diff in the front, so either hub being bad means you don't have anything going on up front)?

 

[gijoecam]

Actually, the 13-54 does have a brown wire, and coincidentally that brown wire does, in fact, control a clutch, but not in the same way as the second-gens. The first gens use an electric clutch on the 13-54 to synchronize the front and rear driveshaft speeds before the motor shifts the lockup collar to engage the front driveshaft.

To pin it down, jack the front end up in the air, start the truck and let it idle, then engage 4high. Then, crawl underneath and verify that the front driveshaft won't turn. If it will turn freely, you've got transfer case issues. Odds are the case is fine and the driveshaft will be locked.

In that case, it's a front axle problem... the most common, of course, are the hubs. If you have automatic locking hubs, those are, BY FAR, the most common culprit. They are an inherently weak design prone to failure when you need them most. A Warn, Milemarker, or Superlift replacement set of manual hubs (with a conversion kit) should be under $200 from just about anyplace. You sacrifice the convenience of the auto lockers for the bulletproof reliability of the manuals.

Of course, there could be other issues as well... u-joint, or differential issues aren't out of the question, but the front drivetrain is pretty robust, save for the hubs.

Good luck!

 

[cweagle]

Guess it's the hubs, can't understand how though

OK, I jacked up the front end (both wheels off the ground), idled the engine in park, and hit 4x4. I could turn the front driveshaft maybe 1/3 turn then it locked, so I guess the output clutch, etc. is OK.

I then spun the tires manually (both directions) for a good while and they never locked up. I can't understand, I cleaned out the hubs very well, soaked them in ATF, and both look good (I think - is there a good picture of what they're _supposed_ to look like?)- all the cam points are there on both the hubs and the thing on the spindle. I'd rather fix these than buy new manual locker,s as I'm only planning on using the 4wd a couple times a year...

 

[gijoecam]

You can spin the wheels until the cows come home... the hubs lock by being DRIVEN by the driveshaft. Spinning the wheels is how the hubs unlock.

The clutch is working as long as the transfer case doesn't clunk or grind when you shift on the fly. The way you tested it does not tell you anything about the clutch. However, the fact that it locks tell you that the transfer case shift motor and lockup collar are working as they should. The play in the front shaft is most likely backlash in the gears combined with slack in the chain. 1/3 turn sounds excessive, but it probably isn't.

-Joe

 

[cweagle]

What you said about the xfer case and the 1/3 turn and all that makes sense. Maybe it was less than 1/3 turn, I wasn't expecting it and didn't pay real close attention.

But hub engagement: it seems like _relative_ motion between the hubs and the driveshaft is what engages the hubs, when the driveshaft first spins up. It seems like spinning the wheels _backwards_ when the driveshaft is _not_ turning is just like spinning the driveshaft forward when the wheels are not turning.

Or I'm full of it, wouldn't be the first time.

In any event, I'm going to get the snap ring pliers out and take the hubs to pieces, and really really really clean and inspect them. Is there a picture of what new cam engagement points are supposed to look like, so I can see if mine are worn down too much?

 

[gijoecam]

The theory sounds good, but that's just not the case... it takes the input torque of the driveshaft to force the lockup... Otherwise, the hubs would lock when you drive in reverse, and unlock when you drive forward, and when in 4wd, you could only drive one direction (which we know isn't true).

I had a verbal description of the engagement process at one point in time... came from the shop manual for the Rangers IIRC, but I can't seem to find it...

-Joe