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Discussion Starter · #23 ·
Welding was on the outside of the bell housing where it mounts to the engine, so it is unlikely that any chips came from there. I did find some rabbit pellit sized chips when I took off the gear to remove my VCU. The gears surrounding the pellits looked fine. I would really like to find the rabbit. Feel free to take a guess.

IMG_20141113_082700.jpg
 

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Discussion Starter · #27 ·
To get the VCU housing out you need to pull the gear and taper bearing in the next shaft over. Tried the pry method. Maybe it works on the 6 speed?

I have included a few more pictures but still have not had time to pull out the VCU and examine it. Hopefully tomorrow.

Hopefully you can see that the bits are not needle bearings.

DSC_0291_bits.jpg

DSC_0293_gear.jpg

DSC_0294_gear2.jpg
 

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Discussion Starter · #28 ·
To get the VCU housing out you need to pull the gear and taper bearing in the next shaft over. Tried the pry method. Maybe it works on the 6 speed?

I have included a few more pictures but still have not had time to pull out the VCU and examine it. Hopefully tomorrow.

Hopefully you can see that the bits are more square than round.

View attachment 166938

View attachment 166946

View attachment 166954
 

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Discussion Starter · #31 · (Edited)
You're disassembling it assbackwards
My initial plan was to just replace the rear cover. I never planned to do a full rebuild. Now I would love to just take it apart enough to find out what is wrong and hopefully repair it, without messing anything up. If I had more special tools and experience I would do a full rebuild.

What is the downside to taking it apart in this manner? Am I going to pull a pin and have parts flying everywhere or something? Does it make sense to replace the rear cover? It seemed to me the the shaft assemblies are pretty self contained anyway.

A. Full rebuild kits cost 900.00.
B. Low mileage JDM transmissions are 1000.00.
C. A Rebuilt transmission is 2500.00.

Backup plan is B, if I can find one.
 

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Discussion Starter · #32 · (Edited)
Dug in a little farther. The VCU seems to have the goo leaking out of it. Also the VCU did turn by hand but it was pretty stiff at about 30 ft-lb of torque at a very slow rate of rotation as measured with my calibrated hands.

Just read a reference that said about 90% of all 1g cars have a failed VCU. Also said that after 20 years the goo attacks the rubber seals even when on the shelf. That said people still drive them and only experience minor drops in their launch speeds? Need to do more digging into the VCU mystery. The thread I read was from 2008 so hopefully someone has figured out how to replace the seals and put the goo back in. Funny hearing people describe what happens when a rebuild might fail. They say it explodes! I am guessing the goo just comes out again.

DSC_0300_vcu_housingcover.jpg

Back of VCU housing cover. Is this marred area normal?

DSC_0301_vcuhousing.jpg

DSC_0302_vcu1.jpg
The goo escaping.

Found places to rebuild the VCU.

http://www.ninjaperformance.com/nin....html?osCsid=8bd4fdaad46b114c77a328dec41bff9e.

http://www.3sx.com/store/comersus_viewItemBundle.asp?idProduct=28685

Not exactly cheap, but more options than were around in 2008
 

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I have an ego problem
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Put it all back together, fill with fluid...add Gorilla Glue....
 

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Discussion Starter · #34 ·
Put it all back together, fill with fluid...add Gorilla Glue....
I agree if you mean fill the VCU with gorilla glue. Thought about just drilling a hole in the case and filling it up. Instantly locked VCU!

Not sure if I am thinking about this correctly but If your tires never slip, the power never get's to the rear end. To activate the viscous coupling there needs to be a significant difference in rpm between the front and the back. If all the tires are traveling straight forward then they all rotate at the same rate. If you are going around corners at a decent rate without slipping your rear end should be tracking the front end.

So, the VCU only sends power to the rear end when the following occurs:

Driving in the snow
Driving in Mud
Pushing your car to the limit so hard around a corner that you lose traction at the front or back.
Bad launch causing a tires to slip.
In a parking lot, cutting the wheel so hard that your rear tires navigate a smaller radius than your front tires.

I guess it is no wonder that 9/10 of our vcu's are not working properly and nobody seems to notice until they see the goo.
 

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Discussion Starter · #35 ·
Tested the VCU. It holds about 2 ft-lbs or torque. Just shy of the 75 ft-lbs required by the specification. My 30 ft-lb guess was pretty far off. I made a video but there are already other videos showing the test.

So the VCU is bad. That said I still have not found the source of the chuncks of metal.
 

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Granny Shifter
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I agree if you mean fill the VCU with gorilla glue. Thought about just drilling a hole in the case and filling it up. Instantly locked VCU!

Not sure if I am thinking about this correctly but If your tires never slip, the power never get's to the rear end. To activate the viscous coupling there needs to be a significant difference in rpm between the front and the back. If all the tires are traveling straight forward then they all rotate at the same rate. If you are going around corners at a decent rate without slipping your rear end should be tracking the front end.

So, the VCU only sends power to the rear end when the following occurs:

Driving in the snow
Driving in Mud
Pushing your car to the limit so hard around a corner that you lose traction at the front or back.
Bad launch causing a tires to slip.
In a parking lot, cutting the wheel so hard that your rear tires navigate a smaller radius than your front tires.

I guess it is no wonder that 9/10 of our vcu's are not working properly and nobody seems to notice until they see the goo.
Does that mean the car is pretty much FWD 99% of the time?
 

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From what I always understood, the VCU just lets the amount of torque vary slightly from front to back. Like 55/45 or 45/55. Not completely 100/0. If it was welded locked, it would just stay at somewhere very close to 50/50. The VCU just has the fluid in it that can change the... friction? Like, the heat from spinning the tires heats up he goo, creating more friction (or something along those lines), so the rear tires' drivetrain pathwag can grab on.

I'm not a drivetrain expert by any means, but this is how I've always understood it to work. Correct me if I'm wrong. I would like to know more about the drivetrain anyways.
 

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Slowly rebuilding...
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Viscous Coupling - HowStuffWorks explains how a VCU works.

The teeth on that shaft look pretty bad. If you want to go the rebuild route, I would look take a look at all of the gears and just buy ones that are missing chunks like that plus a new shaft (I believe that gear is part of the intermediate shaft...) Clean up the case, put in all new bearings in it, (I would suggest) rebuild the synchros, and if the crack is only in the bell housing get a non-cracked one.

It's tough to tell but my guess is those "rabbit pellets" are from the chipping in the gears.

Transmissions can take a surprising amount of abuse. It wouldn't surprise me if that trans worked without any noises even if you fixed it without replacing any gears or the shaft.
 

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Discussion Starter · #39 ·
Does that mean the car is pretty much FWD 99% of the time?
Definitely true for everyone with a blown VCU( again about 9/10 of us).

Probably true for those with a working VCU also. Just sent the ninja a request to see an awd dyno plot of the system. My guess is that initially the front wheels have all of the power until the coupling kicks in, because they are not all rotating against the same surface. I think the power split only occurs after slipping, although I am no expert either.
 

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Granny Shifter
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Definitely true for everyone with a blown VCU( again about 9/10 of us).

Probably true for those with a working VCU also. Just sent the ninja a request to see an awd dyno plot of the system. My guess is that initially the front wheels have all of the power until the coupling kicks in, because they are not all rotating against the same surface. I think the power split only occurs after slipping, although I am no expert either.
Bummer. That means the VR4/RTTT is pretty much a heavy FWD-TT 99% of the time.
 
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