Can the Transfercase VC be rebuilt? (1 Viewer)

[Rusty Marlin]

I don't currently have any problems (knock on wood), but thought I would ask.
The search function shows all manner of threads on yanking it out, but nothing on rebuilding it.

 

[Pin_Head]

No.

Get along without it or get another one.

 

[TurboDennis]

Yes.

You have to drill a hole (or 2) in it, flush out all the caked on oil inside (through the hole(s)), then refill with oil and weld up the holes.

 

[Rusty Marlin]

OK, thank you.

 

[Kernal]

What type/weight of oil, where do you drill the holes, how big are the holes,
what solvent is used to flush it out, how do you weld it back up, ----

 

[TurboDennis]

What type/weight of oil, where do you drill the holes, how big are the holes,
what solvent is used to flush it out, how do you weld it back up, ----

You drill the holes through the flat section (near the input shaft). 3-4mm is usually sufficient. If you make them too small, it will take forever to flush out the old oil. If you make them too big, they will be harder to weld up. Make sure you use a nice, sharp twist drill and controlled pressure to drill, so that you get a nice continuous chip. You don't want small chips falling into the hole.

Gasoline seemed to work best for dissolving the old cooked oil.

Use silicone 10,000 CsT oil to refil. Will need about 80-100ml.

To weld it back up: you take the welder and.. weld up the holes.

It takes a while to dissolve all the old oil and flush it out - old oil will be caked on from overheating, causing the VC to become seized. A good technique is to put some gasoline in, shake it around, let is sit for a couple of hours, shake some more, then shoot compressed air into one of the holes and watch the goo come out the other hole. Once the VC is unseized, spin the two "halves" while flushing. Repeat a few times, until the gas comes out clear and the VC spins with NO resistance. I suspect if you had access to one of those paint can shakers that they use in paint stores, it would probably speed this up quite a bit. Before filling with oil, flush with brake cleaner and dry completely.

This procedure is quite common with the Land Rover crowd. It's pretty easy to do, and the "rebuilt" VC works as good as new.

 

[Kernal]

Good information.

So there's no clutch pack-type lining that gets damaged (like an automatic transmission), just steel plates in a stack?

 

[Rusty Marlin]

According to my research, that is correct. It uses an effect called boundary layer resistance to spin the plates of the slower drive shaft.
The oil heats up where there is "slippage" between layers and gets exponentially more viscus which causes the slower drive shaft to be sped up by the amount of energy the faster drive shaft gave up to heat the coupling fluid. When hot the VC is essentially locked across the drive shafts because of the change in viscosity.

About Viscous Couplers | Quadratec

www.quadratec.com

 

[inkpot]

I don't currently have any problems (knock on wood), but thought I would ask.
The search function shows all manner of threads on yanking it out, but nothing on rebuilding it.

Or just install/use a CDL switch and toss out the VC when it fails, or if you are already in the transfer case for other reasons. We have pulled/disposed of several dozen of them. We already have plenty of doorstops.

 

[LC4LIFE]

I sent @scottryana my old, but still good VC. He was going to see if modding was easy. Not sure where he is on that process.

FWIW, I can hardly tell a difference it's no longer in my transfer case, regardless of conditions.

 

[inkpot]

We have cut one in half, and from what we saw it looked like old RTV between the friction plates. I cant imagine ANY amount of gasoline/solvent flushing EVER getting all that dried up buggersnot out of the housing. There is just enuff room for a thin coating of fluid between each plate.

 

[Kernal]

If someone wanted to give it a try there are solvents designed specifically
to remove silicone oils, but they aren't cheap. Seems easier to pick up an old
working unit that's about to be tossed in the dumpster.

Document Viewer

www.dow.com

Silicone Oil Cleaning | Industrial Silicone Remover Solvents

www.nugentec.com

 

[shocktower]

If someone wanted to give it a try there are solvents designed specifically
to remove silicone oils, but they aren't cheap. Seems easier to pick up an old
working unit that's about to be tossed in the dumpster.

Document Viewer

www.dow.com

Silicone Oil Cleaning | Industrial Silicone Remover Solvents

www.nugentec.com

I was thinking of opening one up and cleaning it and put it back together but if I can clean one without I am wanting to try it, just do not need 6.4 gallons of solvent

 

[scottryana]

I think you would have to get to it before it becomes too gummed up.

We have cut one in half, and from what we saw it looked like old RTV between the friction plates. I cant imagine ANY amount of gasoline/solvent flushing EVER getting all that dried up buggersnot out of the housing. There is just enuff room for a thin coating of fluid between each plate.

 

[ccslider]

I have 2 of them I took out for part time kits

 

[Pin_Head]

I guess it depends on what your time is worth. You could spend a couple of days trying to rebuild one or you could get a good used one from someone that is going to throw it away. The truck drives well without one and good used ones are cheap. Your choice.

 

[scottryana]

Yeah but it is eventually a loosing battle. With age and miles there won't be good used ones. I would like to see some people experiment with different viscosities of oils to increase the "limited slip" factor of the VC, much like the clutch fan. Probably not a big deal for people in the rocks that should just lock their TC but in wet snowy conditions in high range could be a good idea...

I guess it depends on what your time is worth. You could spend a couple of days trying to rebuild one or you could get a good used one from someone that is going to throw it away. The truck drives well without one and good used ones are cheap. Your choice.

 

[TurboDennis]

Or just install/use a CDL switch and toss out the VC when it fails, or if you are already in the transfer case for other reasons. We have pulled/disposed of several dozen of them. We already have plenty of doorstops.

If you live in Arizona, then you should be OK without one. But it's quite helpful in the snow.
Besides that, it has an added benefit of dampening the clunking from the drivetrain. On most USDM trucks it's not very noticeable, because the TQ in the auto tranny helps with that. But if you're running a stick shift (like i am), it's almost a must have. It makes a HUGE difference - you can hear/feel a lot more clunking without the VC.

I also find it quite annoying how so many members here dont appreciate the engineering that went into building these trucks. It seems like everyone wants to just delete everything when it needs service or costs money to replace. It's small things like the VC that made these trucks stand out among all the other crap on the market in the 90's, and i personally take pride in maintaining it to a high standard instead of just deleting all the goodness. /rant over

Either way, this thread is going way off topic. The OP asked if the VC can be rebuilt. It absolutely can be. And it doesnt take a "couple of days". Maybe an hour or two of work in total. You dont have to sit and watch it for hours while the solvent is doing its' thing..

 

[scottryana]

And yes THANK YOU for sending me the VC, I have not had the time to get around to messing with it. I am currently living at the hospital and coming home just to sleep, but I promise I will get around to it and I will document the process! My plan is to drill a hole, drain with solvents and compressed air, and then tap the hole and install a small set screw.

I sent @scottryana my old, but still good VC. He was going to see if modding was easy. Not sure where he is on that process.

FWIW, I can hardly tell a difference it's no longer in my transfer case, regardless of conditions.

 

[Pin_Head]

If the Toyota engineers had intended the VCs to be rebuilt, they would have put a drain plug in them.