Viscous Coupler confusion (1 Viewer)

[DanMedeiros]

With @Shoredreamer leading the charge we are working on regearing a used Tase rebuilt with under-drive gears and new lower low-range gears. We were working on buttoning up the case tonight and realized that the VC of the donor case was fried. With the center diff unlocked the front and rear outputs were still locked together...


I spent the last hour reading threads about the VC but still don't understand if I need one or not. We have two other cases lying around and could pull one out with a bit more work.

Do I loose awd or ABS if I leave the VC out? It seems pretty common that people take it out. Is it just because its an expensive wear part that eventually fails?

My wife and I do a ton of driving (15 weeks a year typically) on icy roads to go skiing in Tahoe so I'm worried about loosing handling performance in these conditions.

Would appreciate any advice you guys have

 

[baldilocks]

You are going to get opposing opinions on this one. I can see where the VC would improve traction on snow and ice. You will undoubtedly be told that it’s a piece of junk that Toyota put in to take up slack and clunkiness in the awd system beginning in 1993; an effort toward refinement.

If I were in your position, I wouldn’t bother with the effort necessary to have a VC in my T-case unless it has super low miles on it. When on snow or ice, engage the cdl and drive accordingly like we have for decades.. This way you are assured to never have a VC lock up on you ever again, it’s not an issue you need while in Baha.

 

[DanMedeiros]

YEah we were all done with the tcase project and then had to pull the rear housing Was hoping to get the new case in the truck this weekend. It does seem like if it failed in the wrong spot it could be real s***ty.....

 

[baldilocks]

It is frustrating when things don’t work out exactly the way we had planned.

 

[DanMedeiros]

its a situation i'm very used too lol. I don't think I haver ever had a wrenching project just work

 

[LandCruiserPhil]

its a situation i'm very used too lol. I don't think I haver ever had a wrenching project just work

Get better help

 

[LC4LIFE]

I just rebuilt my T-case, and left out the viscous coupler. For some time, I had really thought it made a difference in the snow/ice, but I can tell you that after driving is some very slick conditions yesterday I could not tell a difference. At this point I'd say tires make more of a traction difference that the VC ever will. I do like the fact that I saved about 20lbs of rotating mass inside the transfer case, and I assume I can fit a bit more oil in there now, but that hasn't been confirmed.

FWIW - I know of no one that ever had a VC fail, just heard of the ones on MUD.

 

[LandCruiserPhil]

I just rebuilt my T-case, and left out the viscous coupler. For some time, I had really thought it made a difference in the snow/ice, but I can tell you that after driving is some very slick conditions yesterday I could not tell a difference. At this point I'd say tires make more of a traction difference that the VC ever will. I do like the fact that I saved about 20lbs of rotating mass inside the transfer case, and I assume I can fit a bit more oil in there now, but that hasn't been confirmed.

FWIW - I know of no one that ever had a VC fail, just heard of the ones on MUD.

They go bad as I sold mine after it was removed Remember the earlier tcases didnt use a VC.

Its a pump system and even if you gain an ounce of capacity nothing would change IMO.

 

[LC4LIFE]

They go bad as I sold mine after it was removed Remember the earlier tcases didnt use a VC.

Its a pump system and even if you gain an ounce of capacity nothing would change IMO.

Yeah, I know that it pumps and it also appears that the bottom of the VC sits just about the height of the fill plug. I will confirm if there is an oil capacity difference as I am changing the oil this weekend as I now have enough miles on the new gears, etc. to change it. I will post up my findings.

 

[Tools R Us]

I just rebuilt my T-case, and left out the viscous coupler. For some time, I had really thought it made a difference in the snow/ice, but I can tell you that after driving is some very slick conditions yesterday I could not tell a difference. At this point I'd say tires make more of a traction difference that the VC ever will. I do like the fact that I saved about 20lbs of rotating mass inside the transfer case, and I assume I can fit a bit more oil in there now, but that hasn't been confirmed.

FWIW - I know of no one that ever had a VC fail, just heard of the ones on MUD.

That has been our experience, pretty much worthless. Live in the desert, but make trips to slippery places, can't detect any difference in driving. If it was all of that, why was it removed from the 100 series?

Have seen a few dead, locked up ones, only replaced one. Unless the owner prefers to have it, anytime the rear housing is off, we remove them and toss in the recycle bin.

If the parts are handy, can replace the rear cover with a non-VC part and run the longer driveshaft, reducing u-joint angles, chance of vibration. Parts from a non-ABS (FJ80, etc) bolt up.

 

[DanMedeiros]

Get better help

Lol Most of my help is free! Begger’s can’t be choosers

 

[DanMedeiros]

Well I made a round of calls to all the usual vendors today. Kurt was out but I managed to reach Christo at SLEE. Said I could leave the VC out if I wanted, that I would still have awd, but that if both front tires where on ice I wouldn't be going anywhere. Another reputable shop said I couldn't pull it without converting to part time. I think I'm going to trust SLEE with the definitive answer.

 

[Tools R Us]

Well I made a round of calls to all the usual vendors today. Kurt was out but I managed to reach Christo at SLEE. Said I could leave the VC out if I wanted, that I would still have awd, but that if both front tires where on ice I wouldn't be going anywhere. Another reputable shop said I couldn't pull it without converting to part time. I think I'm going to trust SLEE with the definitive answer.

Removing it converts it to the same as a non-ABS '80 series or an early 100 series. Still AWD, the VC is just a brief acting, weak, limited slip for the center diff.

 

[shocktower]

Pull it add 1 quart of you favorite fluid and drive on, oh do the 7 pin mod

 

[cruiserdan]

My wife's 80 has been running without a coupler for 10 years. I have had a good used one ready to go in for some time but the vehicle functions reasonably well without it. I think the coupler is beneficial as my truck works better than hers unlocked in slimy stuff. That being said it isn't that much better to entice me to take her transfer apart and put the backer in. I would fix my truck however.

 

[DanMedeiros]

@cruiserdan thatsbfornthw advice. I’ll swap in and old one. I drive through a lot of sleet on hwy 80 commuting from the coast to the mountains.

 

[richardlillard1]

...anytime the rear housing is off, we remove them and toss in the recycle bin.

You mean you threw mine out?! That was going to make a great paperweight!

 

[Jim S.]

He tossed mine too.

 

[Tools R Us]

He tossed mine too.

IIRC, there was some discussion about it being the right thing to do? So your gears and VC are sitting on the shelf, in case we wanted to return it to stock.

 

[fumann]

Save some space on the shelf for mine.