Tutorial: removing the viscous coupler (photos)

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Walking Eagle said:
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.

borrowed this picture from that thread - the red arrow I added is the tab / 'ear'. I think anyway...
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I'm by all means no mechanic but wouldn't it be the tab with the green arrow since it looks more accessible? The red arrow looks like it's postion would be at the top and I'm not sure about getting a pry bar up there and getting leverage. Please, please, please correct me if I'm wrong.

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does the fluid refill amount change when the big assed 40 pound viscous coupler is removed from the transfer case innards....

normal fluid fill is 1.7 quarts - yes?

should I put in closer to three quarts when the coupler is removed?

just curious
 
borrowed Waynes shop and tools and used his Lisle flat nose retention ring pliers
snap ring took all of thirty seconds

this job is super easy if you have the proper tools and setup

oif course I have a 1 inch body lift on the truck (helps with the top bolts) and was working in a pit (and not lying on my back in the driveway.

I dont know how much dif fluid I put back in as I pumped it out of a 5 gallon bucket (beats pouring it out of the 1 gallon jug of gear oil I bought for the job)

I wish I would have done this a long time ago.

thanks Wayne
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not trying to open a can of worms, but do you think removing the VC will negatively affect the performance of the truck in the snow? I admit that the 80 is probably the most stable snow vehicle i've ever driven.
 
concretejungle said:
not trying to open a can of worms, but do you think removing the VC will negatively affect the performance of the truck in the snow? I admit that the 80 is probably the most stable snow vehicle i've ever driven.
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That is a very good question.

Would it not perform the same as the 91 & 92 models when removed?
I don't recall anyone who owns or drives both types of drive trains ever making reference to snow driving or any comments, pro or con.

From my limited amount of snow driving with the BFG AT's and in heavy rain and flooded roads with the original stock Michelins, I always found that having the center diff locked helped increase stability at higher speeds.

Having the center diff locked would override the functions of the viscous coupler would it not? The torque split would be different when locked and that may be what makes the difference. The torque split versus traction between front/rear axles and right/left wheels is beyond my understanding so I'm guessing on that.
 
ppc said:
That is a very good question.

Would it not perform the same as the 91 & 92 models when removed?
I don't recall anyone who owns or drives both types of drive trains ever making reference to snow driving or any comments, pro or con.

From my limited amount of snow driving with the BFG AT's and in heavy rain and flooded roads with the original stock Michelins, I always found that having the center diff locked helped increase stability at higher speeds.

Having the center diff locked would override the functions of the viscous coupler would it not? The torque split would be different when locked and that may be what makes the difference. The torque split versus traction between front/rear axles and right/left wheels is beyond my understanding so I'm guessing on that.
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I have not driven an older model but in my experience i have found that with the CD unlocked proved to be the most effect and stable "on road in the snow" driving. I felt like i was in a real big subaru or something.
 
In the original picture of the coupler, I can't see where this looks faulty. I'm guessing my bad one that I will be replacing soon will show no signs of wear either.

What part seizes up with these? Because it looks fine.
 
It's a sealed unit, no way to tell without cutting it open.

Tools cut one open IIRC.
 
Also, what kind of oil does the transfer case require? And do I just fill it to the top line level? (if there IS a top line like there is with diff's)
 
Ahh I didn't know that! So theres moving parts inside it, too. I thought it was just what could be seen outside.
Thanks!

Ebag333 said:
It's a sealed unit, no way to tell without cutting it open.

Tools cut one open IIRC.
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If it has no fluid at all, I wouldn't imagine it'd last very long.
 
I removed the fill plug and the oil looks good, it's an amber colour as opposed to red colour that is in the rear diff.

What oil do I refill the trans case with after I replace the VC?
 
75w90 GL5 grade diff oil.
 
Ok they sent me some sort of FAN instead of a VC.. Tell me I have to buy a whole trans case for like $950 and theres no way I'm doing that.

Toyota want $550 and theres also no way I'm doin' that.

So: With my centre diff lock ON. There is no difference if the VC was in or out, right?
 
crooozer said:
So: With my centre diff lock ON. There is no difference if the VC was in or out, right?
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A seized VC acts just like a locked CDL. So the answer to your question is, yes.

You do not however want either a locked CDL or seized VC with both drive shafts in and on pavement. With only one DS in, you do want the CDL locked or VC seized (as otherwise you won't go anywhere).
 
crooozer said:
So: With my centre diff lock ON. There is no difference if the VC was in or out, right?
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Even with the CDL off there is no difference 99.9% of the time. The VC only comes into play if a wheel is slipping when the CDL is unlocked. It works like a limited slip differential to transfer torque automatically to the end that is not slipping. I'm guessing the Toyota put it in there so that people wouldn't have to know when to push the CDL button. They made it automatic because most of the people who bought FZJ80 didn't want to know that much about how they work. So the bottom line is they aren't necessary and their function can be duplicated by the CDL switch.
 
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