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Discussion Starter · #1 ·
Within the next 6-12 months I intend to fully rebuild the splined disconnect / coupling unit on my new-to-me 2005 TB, while I do a complete suspensión overhaul. In the meantime, I thought it worthwhile to inject some grease via the actuator port.

While doing the front brakes last night, I popped out the struts and added a 1/2” spacer plate. That process allowed space to easily remove the actuator off of the disconnect unit. I pumped as much synthetic grease as I could through that hole before reinstalling the actuator. I’d estimate I was able to get 1-2 ounces into the unit before grease was forced out and it seemed topped up. That is a rough estimate based on a number of full pumps on a standard sized grease gun.

Questions: assuming a typically “dry” or “drying” disconnect unit with aging factory grease (147k on the truck), am I safe assuming this type of home brew maintenance should buy some months of time before rebuild? Is there a known risk or downside to the actuator from grease migrating up the spring-loaded tube?

Any thoughts or experience shared on this is appreciated. My experience to date has been in the Jeep and Toyota directions, so I have to confess I’m still in the learning curve here. Thanks!
 

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OK -- El .....

Short story time --- relax, 'cause there's a moral to it .... wait for it ...

I'd have customers come into the shop requesting that I "pack their wheel bearings" all the time. I've always tried to dissuade them from this rather useless job as it is rife with the possibility of contamination and ruining the bearings a lot faster than just leaving them alone!

Times were, that I'd get persuaded to do it anyway ... and when I got the hubs off --- they were filled completely with about 4lbs of wheel bearing grease. FULL!

Now --- think for a moment .... just HOW MUCH OF THAT GREASE GOT TO THE ACTUAL BEARING RACES OR ROLLERS AND PROVIDED SOME LUBRICATION?
How much?​
If you see the flaw in my uneducated customer's logic, you KNOW that damned little ever got there and, frankly, only the grease that was immediately on and applied to the rollers and races --- ever got into contact with them.

The rest of the 3lbs 15.5ozs of grease was still a virgin; it was bright, clean and had never ever touched anything metallic in the whole time it was inside that hub.

Get it? Here's a mnemonic for you: "GDM" <grease don't migrate>.

I kinda really liked to find this ignorant situation in a new customer's bearing hub area ...'cause it gave me 2-4 months worth of new, clean, free bearing grease.
.
 

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Discussion Starter · #3 ·
First off, thanks for your reply. You make a great point. This reminds me of my first go at repacking the front wheel bearings on my Land Cruiser about a week after I bought it. The driver’s side was what I expected: dirty, old grease which I dispensed with and repacked with new. The other side was old grease with a bunch of newer red grease outboard of the older crap deeper in the bearing. It wss as obvious that for whatever reason, and recently, someone had the wheel and outer hub assembly off. Really made me wonder not only what the motivation was for that but also if the last guy even set the preload correctly.

I’m thinking now that I just basically emulated what that last guy did to my Cruiser.😕

I’m going to accelerate my timeline for pulling and rebuilding that disconnect unit. Who knows what crap old grease I might have forced into the assembly? I read a lot about the units basically going dry as the factory grease would migrate out away from the innards and even spit out of the unit in some cases. But clearly the fix isn’t to pump in grease through the actuator port.

Thanks again man!
 

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YW ... on parts that are deep and away from servicing on a logical basis, I like to use CV grease. It clings like stink and it is extremely slippery and impact/shock/pressure proof.

It also isn't much affected by heat.
 

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BTW: on 1959-1960-ish GM products, they use ball bearings for the front wheels.

You didn't so much clean and pack them on a schedule --- you replaced them so much that the hubs got loose from the number of times you had to knock the old races out and new races in.

Those front wheel ball bearings were good for (a slight stretch here) about 1500 miles before you have one or all four bearings go bad. It wasn't for lack of lubrication ... it was lack of bearings being able to bear the loads.

Ball bearings have a very tiny contact patch and what IS in contact is under terrific moment/loads constantly ... at the same time spinning in a very hostile environment.
 

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Discussion Starter · #6 ·
I can see why the ball bearing idea you mention didn’t last long. Back on the CV grease though: when I go to rebuild that unit, I’ll definitely give the CV grease a go. Any old generic OK or do you recommend a certain brand? Or maybe a better question would be “which brand(s) might you avoid?”

I can be king of the overthink at times. Past experience has taught me that my overthinking can result in the appearance of no thinking having happened at all!
 

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I think any specific CV joint lube would be great - especially from a larger company like Castrol or Veedol --- although I've been out of the CV-joint grease installation business for over 16 years now. If it says it's for CV joints, then I say go for it.

Believe me --- if your lucid enough to know you're crazy, you're really sane in the first place.
 

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Within the next 6-12 months I intend to fully rebuild the splined disconnect
My experience has been that you can count on replacing the shift-fork; you can "almost" count on needing at least one needle-roller bearing; and the "gear" that bearing rides on is likely to be scored as well. And, of course, a couple of grease seals.

I re-pack the thing with standard wheel-bearing grease. NLGI "GC-LB #2". I've used "red" GM-Chrysler grease, next time I'm gonna experiment, try the "grey" Ford moly-fortified grease.





By the time you buy a shift fork, bearing, gear, two seals, and the anaerobic gasket maker, and then add your labor to change all that stuff, "most" folks would pitch the old one in the scrap heap, and merely cram a brand-new axle disconnect in place. About a hundred dollars, sold under several brand-names with varying warranties. My suspicion is that they're all made by the same factory, but put in differently-labeled boxes.

Of course, the "new" unit is a Chinese knock-off of the Genuine GM part; and God only knows what kind of grease--or how much--they slather inside.

The aftermarket shift fork may actually be an improvement over the Genuine GM fork. Both shift forks are crappy, soft aluminum with no steel or bronze inserts on the contact pads. The aftermarket unit has three contact pads instead of GMs two contact pads. When it's me, I put the aftermarket fork in the GM housing, with mainly GM guts. SOMEDAY, I'm gonna collect all the worn-out shift forks, and see if I can't rebuild them with a brass/bronze wear pad like they should have gotten to begin with.

Be sure to anti-seize the housing where it presses into the oil pan, so it comes off easier next time.
 

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I did exploratory surgery on the transfer case in my '86 K5 ---- just because I wanted to.

Since the High-Low shift fork had worn through the nylon-ish antifriction pads, I just split some copper tubing and formed it around the inside of the "C-shaped" fork and brazed it into place at the ends.

I have done this repair multiple times and never had any troubles. I wonder if the forks on our TBs would accept the same treatment with smaller tubing?
 

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Can't solder to aluminum. I don't think aluminum can be brazed, either. MAYBE there's enough material for installing brass/bronze flat-head screws into the contact pads, to be a wear surface.

I don't have a good solution beyond TIG-welding fresh aluminum to the worn contact pads. Which is why I haven't progressed with the idea.
 

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Discussion Starter · #11 ·
I just bought an aftermarket disconnect with actuator attached for $76 on an eBay. It was a new, open-box return, make-an-offer score. If I can spare the time I'll start a thread and post photos as I disassemble my original unit alongside the new. But if life lays on the typical bitchslap to my spare time I may cave and just slap in the aftermarket and save the OEM for a future rebuild. I've got lower arms, upper ball joints, struts (MOOG 81114 springs),hub units, tie rod ends, end links, outer axle seal , the whole 9 yards all incoming so that I go in once, and completely.

I appreciate the feedback gents, the idea of brass screws as a wear surface on the fork was especially intriguing and sounds like it might be the best-fix situation for the weak fork. - Cheers -
 

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I re-pack the thing with standard wheel-bearing grease. NLGI "GC-LB #2". I've used "red" GM-Chrysler grease, next time I'm gonna experiment, try the "grey" Ford moly-fortified grease.
Of course, the "new" unit is a Chinese knock-off of the Genuine GM part; and God only knows what kind of grease--or how much--they slather inside.
I remember correctly, the GM recommends filling the cavity of the inner intermediate shaft bearing housing with 55-65 cc (1.86-2.20 oz) of grease, GM P/N 12377985 or equivalent
 

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GM P/N 12377985
GM "Chassis grease", (not "wheel bearing" grease) NLGI rated, but without the rating actually being printed on the tube. At least, I can't find a rating. Being chassis grease, it'll be "L" but theoretically could be LA or LB, LB is both "better" and enormously more common. Wheel bearing grease would be "G", with quality grades of A, B, or C. "C" is best, and again, most common. It's pretty easy to make a grease that's dual-rated and high quality--both LB and GC, like the two I pictured in the earlier post.

(I have NO idea why GM wouldn't specify a dual-rated grease; that way it wouldn't matter which application you were using it on. I buy dual-rated grease in 14 oz tubes for grease-gun/chassis use, and the same grease in one-pound tubs for wheel bearings, exactly as pictured in my previous post--so if I run low in the tub, for example, I can squirt the same stuff from my grease-gun and finish the wheel-bearing job. Or if I ran out of grease in the tube, I could re-fill from the tub. Saves on inventory hassles and reduces my trips to the parts store.)

Similarly, it could theoretically be #1--#5 for viscosity, but virtually all "chassis grease" and "wheel bearing grease" is #2. Lower number is lower viscosity. I've got a tube of engine assembly lube that's rated as "00" which I think is thinner than the official NLGI rating system goes. #5 grease would be about as "hard" as a block of cheese.

www.amazon.com/Genuine-Fluid-12377985-Chassis-Grease/dp/B000QIVOMY

 
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Discussion Starter · #14 ·
Schurkey:

There's also a needle-roller bearing securing a "gear"; when I rebuild the unit I always replace the needle-roller bearing with a wider one, and the old bearing usually destroys the machined surface of the "gear" that it rides on. So it gets a new "gear" to go with the new, wider bearing. MOST of the time, a bearing, a "gear" and a shift fork, plus fresh grease and seals, is all the thing needs to work like new.
I read the above on another thread, do you have a part number or direction to look for that wider needle-roller bearing? I tried to spare you the question by searching around but have as yet come up empty handed.
 

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"I" have had this work. Far as I know, no-one else does this. That may be a warning to you. Or not.

The housings I've worked with have JUST BARELY enough room to cram the wider bearing in place. Maybe the Chinese housings have more--or less--room for the bearing. Maybe I've just been lucky.

Koyo bearing HK4016

Note damage on bearing surface of the old "gear". Gotta replace the "gear" along with the bearing.

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GM "Chassis grease", (not "wheel bearing" grease) NLGI rated, but without the rating actually being printed on the tube. At least, I can't find a rating. Being chassis grease, it'll be "L" but theoretically could be LA or LB, LB is both "better" and enormously more common. Wheel bearing grease would be "G", with quality grades of A, B, or C. "C" is best, and again, most common. It's pretty easy to make a grease that's dual-rated and high quality--both LB and GC, like the two I pictured in the earlier post.
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The descriptions I've seen for 12377985 suggest that it's chassis lube, not for use in wheel bearings.

But using a GC-LB rated grease isn't going to hurt anything, because it still meets all the requirements for LB-rated grease in addition to all the requirements for a wheel bearing lube.
 
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