Tutorial: removing the viscous coupler (photos)

[RavenTai]

the VC does not react in so many revolutions, it is more sensitive to rate, if a tire was slipping slowly it would not do anything ever, not sure about the "Humping" (locking phase) but the resistance phase is instantaneous and strong and gets stronger with more RPM difference

 

[Rusty Phillips]

Im wondering if you can dissassemble the VC and change / refill the fluid (silicone?) inside it?

kind of like Toys R us was doing with fan clutches

more pics of the removed VC please.....

 

[MikePL]

Do you think oil is the culprit? The VC is seized. The seizing is caused by overheating, so I suppose some elements are bent, melted or broken. But if it is just a question of oil, then I can disassemble it and have a look. I've nothing to loose anyway.

 

[Walking Eagle]

Awesome writeup and photos.

I hope this doesn't ruin your day, but you can get that c-clip of in 10 seconds with the right set of snap-ring pliers.

GuruHayes

yep - from the t-case bearing thread

You'll need a Craftsman Lock Ring Pliers (Sears item #00947386000 Mfr. model #47386)

https://forum.ih8mud.com/showpost.php?p=1002781&postcount=6

might be a better one out there but this one works, though it is tight. I was probably somewhere between 10 seconds and 20 min.

 

[Walking Eagle]

6. Now you have to separate the back of the T-case from the rest. You can use some sophisticated pullers and try to separate it, but you can also go the 'brute-dummy' way and simply point a flat screwdriver to the edge and bang it with a hammer. You will end up with a few dents on the mating surfaces, but you can tap them back to flatness with a hammer. Wiggle the screwdriver around to make sure you gave a gap everywhere. Remember to do it alternatively on both sides (left-right-left-right...) of the case.

There is also an 'ear' on the housing, that you can just use a pry bar on on the drivers side, the passenger side there is a point that you can hit with a drift punch. I tried the rubber mallet mehod, that didn't work worth a crap, then I made a little stap holder to mount into one of the threaded holes on the housing and hooked a strap to the frame to try to pull. Nothing. Pry bar on the tab is waht finally did it for me.

here's where Hayes talkes about using a drift punch

https://forum.ih8mud.com/showthread.php?t=113268&highlight=output+seal

borrowed this picture from that thread - the red arrow I added is the tab / 'ear'. I think anyway...

 

[alia176]

yep - from the t-case bearing thread

You'll need a Craftsman Lock Ring Pliers (Sears item #00947386000 Mfr. model #47386)

https://forum.ih8mud.com/showpost.php?p=1002781&postcount=6

might be a better one out there but this one works, though it is tight. I was probably somewhere between 10 seconds and 20 min.

There may not be a Sears in Warsaw, Poland

 

[MikePL]

I've bought a set of professional lock ring pliers a few hours after the task. I had four kind of such pliers but none of them worked for the tight place where the ring is. Yes, I know I could have written 'get SST no.XXXX and the ring will pop off', but I wanted to do the task with the simplest set of tools possible, to encourage people that such things can be done without a complete car workshop.

 

[UpsideDown]

I just completed this surgery on IronYuppy's 80 series at my shop this afternoon.

It's a very simple job, and in total the VC removal probaly took about an hour and a half to two hours with a few interruptions from the phone, my apprentice, and ensuring that everything was cleaned and inspected before reassembly.

I can't think of anything that would complicate the Re & Re other than forgetting to install the oil pump drive or something similar. In doing a final inspection of things, I have also decided to replace the rear u-joints as they are not totally smooth anymore (original units still in place).

Anyhow, thanks for the write up and photos. I could post photos as well, but they'd look almost exactly the same.


John

 

[Romer]

Did this fix Ironpuppy's binding issue? If so, pictures of the coupler with a guess what caused it would be useful in this thread.

 

[concretejungle]

Did this fix Ironpuppy's binding issue? If so, pictures of the coupler with a guess what caused it would be useful in this thread.

yes, please do tell. I have a terrible suspision that i may be having some of the same issues.

When i turn sharp in a parking lot, i feel an almost wiggle as if a wheel is loose, or an inner wheel is binding.

 

[CJF]

yes, please do tell. I have a terrible suspision that i may be having some of the same issues.

When i turn sharp in a parking lot, i feel an almost wiggle as if a wheel is loose, or an inner wheel is binding.

Don't forget that it's easy to test...

 

[landtank]

I get a groan from somewhere when I shift from D to R or vice versa. I've suspected the VC for 4 years.

 

[IdahoDoug]

Rick,

I get a muffled groan also once in a while on D to R in the 97 - never on the 93. Almost a brief hydraulic whine - perhaps .5 seconds.

Hey for you guys thinking of opening your VCs just a word of warning to be cautious in case there's a pressure buildup of some sort in it. I honestly don't know if it can still exist after the unit's cool but I know in operation they can have tremendous internal pressure from heat. Use caution, eye protection, condom, etc

DougM

 

[UpsideDown]

Did this fix Ironpuppy's binding issue? If so, pictures of the coupler with a guess what caused it would be useful in this thread.

I'll post an update after a test drive.

If IronYuppy gives his permission, the VC unit may have a play date with Makita and Zip Cut

 

[concretejungle]

Don't forget that it's easy to test...

I've checked for loose wheel bearings, but i have not tried to put it on jack stands and try to lock the CDL and see what's spinning.

 

[IronYuppy]

I'll post an update after a test drive.

If IronYuppy gives his permission, the VC unit may have a play date with Makita and Zip Cut

Hell, yeah, let the autopsy begin!

 

[IronYuppy]

I've checked for loose wheel bearings, but i have not tried to put it on jack stands and try to lock the CDL and see what's spinning.

Don't rely 100% on that test. I did the same thing, and everything appeared normal. I guess it depends on how much resistance the viscous coupler gives when you're spinning the wheels freely.

The hard-boiled test was to lock the centre diff lock in high range, remove the front shaft, and go for a drive. In my case, disengaging the front axle from the drivetrain cleaned-up all the noise/binding issues, so that proved the problem was somewhere at the other end of the driveshaft.

 

[CJF]

Don't rely 100% on that test. I did the same thing, and everything appeared normal.

You did the following test, and the raised wheel spun freely??

Another way to find out if your VC is dead is to raise one wheel (tranny in N, transfer case in N). In the N/N position the wheel should move rather freely when you rotate it by hand.

 

[IronYuppy]

You did the following test, and the raised wheel spun freely??

yup.

 

[RavenTai]

Don't rely 100% on that test. I did the same thing, and everything appeared normal. I guess it depends on how much resistance the viscous coupler gives when you're spinning the wheels freely.

that test works great to find a locked up VC, if you are getting binding from the VC wile driving but not static you should look very closely at all your tires and make sure they are all the same size.