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Vac disconnect


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Its unlikely the actual Vac disco itself is causing this problem. More likely a faulty part for problem with the fork or possibly even the T case itself.

 

What is the actual symptoms?

 

BTW, all the disco does in engage front axle. The Tcase shifter inside the truck puts it in 4WD. Hows the chain in the T case? How many miles?

 

CW

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You can lock the axle in the engaged position. Someone posted a write-up, complete with pictures, awhile back. It's easy to do -- we've done it on trail rides.

 

As Longshot noted, though, that only locks the axle. If the transfer case is jumping out of 4WD, you have other problems than the axle disconnect.

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Pop the c-clips off the shaft on the CAD motor inside the housing. Slide the shift fork over and shim it with a stack of washers, and reinstall the clips. It takes a bit of fiddling until you get the right amount of washers.

Jeff

 

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  • 4 months later...
OOOOR you could get 1 piece shafts with the 297x ujoints, and not have to worry about the u joint failure. Thats what I did.

 

yeah, but the shaft is no thicker than a normal shaft. so, by getting a 297 shaft, the ears are drilled out more for the larger ujoint caps, and your problem IS no longer ujoint failure, but major shaft failure

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but...(and there always is a but ;) ), if a shaft breaks that's it...just the shaft. If the UJ fails, it takes both the inner and outers ears with it, generally, and can even fubar the ball joints and/or knuckle. It's all in planning the failure :D

 

I just scored a 95 YJ outer with the 297 a few weeks ago. It's now stashed in the parts pile, and it will go in along with a 297 equipped driverside shaft when I lock the front. I'm keeping the CAD and unshimming it so I can lock/unlock it with a manual vaccuum switch. That's all on the '08 calender plan.

 

Jeff

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I use blue on lower temp, non-gasoline contact surfaces, like the disco housing cover. I use it on diff covers too without any problem. I've used it on the VC before, but I can't say it does the greatest job.

 

I've got a paper gasket on the D44 diff cover now, and it's working swell. When I regeared it, the install kit came with a paper gasket and I tried it for the first 500 mile break-in. Not a single drop, so when I drained and refilled it, I went with another paper (Felpro, I think it was). All is still good so far.

 

The key, regardless of what you use as a gasket, is surface prep. Make sure both surfaces are flat and squeaky clean, and if using RTV or similar, do not overtorque. I prefer cleaning the surfaces with brake cleaner.

 

Jeff

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OOOOR you could get 1 piece shafts with the 297x ujoints, and not have to worry about the u joint failure. Thats what I did.

 

yeah, but the shaft is no thicker than a normal shaft. so, by getting a 297 shaft, the ears are drilled out more for the larger ujoint caps, and your problem IS no longer u joint failure, but major shaft failure

 

Dude where do you get this stuff..you should be a comedian!!! :D :roll: :eek:

 

The problem that usually occurs is the axle flexes or twists. This twisting causes the caps to get "spit" from the U joint. Once this happens the trunnion slams into the side of its bore and either snaps off or holds and takes out the ears of the shaft. This happens with 260 as well as 297 Joints. Its just slightly less likely with the 297's. This flexing/twisting is also why most brakes happen on the short axle shaft. Its stiffer so it flexes less and breaks more.

As you know, by going to the 297 joint you get a larger turnnion, stronger casting of the trunnion and slightly bigger caps. Bigger makes it a bit stronger.

But the weak link is usually still the joint or more directly the 3/4 clips that hold in the U joint caps in the axle. Notice all alloy or afetrmarket shafts take full circle clips? Less likely to get "popped"!

 

SO, the issue or weak link is not a "drilled" out axle shaft...... :roll: :brows:

 

CW

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The factory U joint is the weak link. 260 or 297 no difference, they are weaker than the axle shaft. They are weaker still when the wheel is turned, weakest at full lock.

Can you break a axle shaft and leave the U joint intact, SURE but its FAR MORE likely the U joint will fail taking out the shaft in the process.

the problems your speaking of happen when people add HD joints that are WAY strong. THEN the weak link moves...could become the ring gear or Pinion or the axle shaft.

 

On my TJ, I added the Hi Pinion axle like on our MJ's only I went with a newer one piece shaft version. Then I added a WARN 5 on 4.5 hub kit and alloy inner shafts. The kit comes with alloy outers with full circle capabilities. Then some slightly stronger solid 297 joints and of coarse full circle clips. My weak link will be the hubs them selves. I WANT this because I am in control of what breaks and this hub is relatively inexpensive and SUPER easy to change!!

 

Image Not Found

 

I cannot find my pics of three shafts we broke one right after the other on the same obstacle. All U joint failures.

 

 

CW

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