How well does the "AWD" system function with the viscous coupler removed (1 Viewer)

[rc51kid]

How well does the "AWD" system function with the viscous coupler removed in real world driving in slush, ice and shallow snowy roads? I am 99% sure that i will toss the VC when i install gears in my transfer case. I am not really 100% interested in a full part time system but not 100% opposed to it. It just sounds like extra cost for very little benefit.

I do drive on mountain roads that get snow and are not plowed. Usually they just let it melt off in a few hours. I dont worry about getting stuck, i just want to keep it as safe as possible driving around. I know with the VC remove i will basically have 3 open diffs. How will a three open diff system drive in poor traction compared to a RWD truck that has done the part time conversion? Will it be any better at all? Or is it really just going to be as soon as any ONE wheel slips that wheel will get all the power?

 

[cme4lyt]

I think this is one of those ‘how long is a piece of string’ questions ?

If you have experience with 4x4’s, you know how to drive in different weather conditions, you know how to read/judge the road, you’re experienced at this sort of thing, ......it will be no big deal.

Now, if someone without your experience and hindsight drives this rig, that’s a whole different question....

 

[JeepinPete]

I find the VC to be about useless in the snow. It drives like the transfer case diff is open. I just push the button on the dash and lock up the transfer case, find it drives much more predictable in the snow that way.

 

[Pascoscout]

Please correct me if I am wrong here but as I understand the way the VC works is it transfers torque from the axle that is slipping to the axle set that is not slipping. It's basically two metal plates with fluid separating them. As one plate spins faster (wheel slipping) it turns the fluid faster which causes the other plate to try and catch up thereby transferring the torque to the non slipping axle. Removing it would require you to either have another way to connect the plates or lose the ability to drive that axle at all. Seems to me that if you just took it out you'd only have 2wd in high range and no 4wd high option at all. Think that's where the part time kit comes in as it give you 2wdH, 4wdH and 4wdL. So without the VC or a part time conversion it would not be like 3 open diffs but would be essentially a RWD truck. Once in 4wd low it should be the same as stock since that would lock the center diff and drive both axles again.

 

[rc51kid]

Please correct me if I am wrong here but as I understand the way the VC works is it transfers torque from the axle that is slipping to the axle set that is not slipping. It's basically two metal plates with fluid separating them. As one plate spins faster (wheel slipping) it turns the fluid faster which causes the other plate to try and catch up thereby transferring the torque to the non slipping axle. Removing it would require you to either have another way to connect the plates or lose the ability to drive that axle at all. Seems to me that if you just took it out you'd only have 2wd in high range and no 4wd high option at all. Think that's where the part time kit comes in as it give you 2wdH, 4wdH and 4wdL. So without the VC or a part time conversion it would not be like 3 open diffs but would be essentially a RWD truck. Once in 4wd low it shouTld be the same as stock since that would lock the center diff and drive both axles again.

This is all well documented by people much smarter than me. I also dont know the exact specifics because i have not researched the exact "how to" while i am in the case. But basically it is easy to remove when the case is apart. You then have a system that does not "know" that the front is turning differently than the rear. it just runs with the center diff open. The VC it is a part known to fail and basically leaves you stuck in "4WD" with a lot of binding in the drive line on dry pavement. It might not be common but it does happen.I think maybe you need to add something simple like a CDL but i already have that.

If i am wrong then i stand to be corrected.

 

[clx16]

look at post 13 Tutorial: removing the viscous coupler (photos)

 

[scottryana]

If you do decide to go Part-time, and you are just going to throw you Viscous Coupler in the garbage please PM me. I have an experiment I would really like to try.

Thanks!

 

[rc51kid]

look at post 13 Tutorial: removing the viscous coupler (photos)

Thanks. That is what i understood. I guess what i am asking is does it make much difference in real world driving.

 

[clx16]

I still have mine and is in good working condition so I can only vomit what I have read and understand. Without the VC you could introduce some clunk that some (not all) have reported, and you may want to pay 50-60 dollars to install a center diff lock switch if you haven't already for the rare chance you have one tire have way less traction than the others.

If mine goes bad, i would rather buy a 900 dollar parts rig than buy a new VC for the same money. but I would likely just delete like others are saying. I've read other people saying that at a certain tire size or lift (i can't remember which) the VC has to come off.

You mentioned snow... I think it is generally recommended to have the center diff locked for all snow and sand driving but I could be wrong on that. It has not been stated that you only lock it if you have an older 80 or you did the VC delete, just standard rule to lock it.

 

[LC4LIFE]

I have experience an 80 with a VC and without on icy roads. I experienced that the one without the VC would act like a rear wheel drive vehicle and the one with the VC would not. For example, I was on a slightly uphill road making a right turn. Without the VC, starting out you could easily get the rear to spin, but with the VC and a little more throttle I could get the front to pull a bit. I could not make that happen sans the VC. This is what I experienced although it was nearly ten years ago I remember it clearly as they both behaved differently. I would be less inclined to believe that any VC at 20 yrs old with 200K or so miles on it would perform as well as I experienced. That experience has also convinced me to leave mine in as long as I think it is working correctly. I do live in snow and ice periodically, but if I was in AZ it would be out in a heartbeat in exchange for a part time kit.

 

[Howard705]

It still takes more than a 2x to get spin- NO VC is the exact equivalent to driving older Blazer/ramcharger/bronco or old trucks in 70s that had NP203 tc. That's how they worked. the 80 TC wITH VC functions like a J*** with BW Quadratrack.

 

[JeepinPete]

The best vehicle I have driven in the show is a Jeep Wagoneer with a NP229 transfer case. The VC in that case worked exceptionally well. The older Borg Warner case I had in my '79 Cherokee were open diff AWD, didn't hold a candle to that Wagoneer. I also owned a Dodge Durango with a NP242 transfer case, also open diff AWD, was inferior.

I guess I shouldn't be so critical of the LC. It falls between the Wagoneer and the others. Mine is pushing 300k, so it might just be worn out (and no Wagoneer in making 300k miles ), but the rear end on my truck likes to step out if I do not have the center diff locked. OTOH, it never gets to the point of one tire spinning like I experienced in the old Cherokee and Durango.

 

[Douglas S]

I have experience an 80 with a VC and without on icy roads. I experienced that the one without the VC would act like a rear wheel drive vehicle and the one with the VC would not. For example, I was on a slightly uphill road making a right turn. Without the VC, starting out you could easily get the rear to spin, but with the VC and a little more throttle I could get the front to pull a bit. I could not make that happen sans the VC. This is what I experienced although it was nearly ten years ago I remember it clearly as they both behaved differently. I would be less inclined to believe that any VC at 20 yrs old with 200K or so miles on it would perform as well as I experienced. That experience has also convinced me to leave mine in as long as I think it is working correctly. I do live in snow and ice periodically, but if I was in AZ it would be out in a heartbeat in exchange for a part time kit.

I have to say I totally disagree. I've driven my 80 in 2wd and in 4wd with the CDL unlocked (no VC) and I can't stress how differently it drives in 2wd vs 4wd. With mud tires on icy roads my 80 was practically useless in 2wd, I was locking the rear diff just to get through intersections whereas it drives just fine in 4wd with no VC.

OP,
Early 80's didn't have VC's from the factory so I wouldn't worry too much about driving without one. VC is probably marginally better for on road use.

 

[Heckraiser]

I've you've ever driven any other plain-old 4x4 vehicle in the snow, there is your answer. Perfectly fine on any surface other than the binding you'll get doing a tight turn on dry pavement.

 

[nukegoat]

If you do decide to go Part-time, and you are just going to throw you Viscous Coupler in the garbage please PM me. I have an experiment I would really like to try.

Thanks!

I JUST threw mine out. Damn.

 

[Izeloz]

I have a '91, so no VC. I DO have a CDL switch and a LOKKA automatic locker in the rear. I also live where we get snow, ice, and slush. I have never had a vehicle that did as well in the snow. My cousin works as a ski patroller and has borrowed it a few times to get to work when the roads are especially nasty (he usually drives a 2001 TRD Tacoma, and apparently the Cruiser is much better in the snow). I usually don't even lock in the CDL unless things get really bad and I am going slow. I might kill a bus full of nuns soon, but in the meantime I am very happy with the slippy road performance of my setup.

 

[Tools R Us]

Please correct me if I am wrong here but as I understand the way the VC works is it transfers torque from the axle that is slipping to the axle set that is not slipping. It's basically two metal plates with fluid separating them. ...

Never counted, but a few more than two.

As one plate spins faster (wheel slipping) it turns the fluid faster which causes the other plate to try and catch up thereby transferring the torque to the non slipping axle. ...

Kinda works as a weak, briefly acting, limited slip between the two drive shafts.

Removing it would require you to either have another way to connect the plates or lose the ability to drive that axle at all. Seems to me that if you just took it out you'd only have 2wd in high range and no 4wd high option at all. Think that's where the part time kit comes in as it give you 2wdH, 4wdH and 4wdL. So without the VC or a part time conversion it would not be like 3 open diffs but would be essentially a RWD truck. Once in 4wd low it should be the same as stock since that would lock the center diff and drive both axles again.

Without the CDL engaged it's AWD just like any other AWD vehicle. The VC adds a weak, briefly acting, mostly useless, limited slip to the mix. It is a fluid coupling, so like any device of that type, it's best performance was when the fluid was fresh, so in this case, ~20yrs ago. Removing the VC has very little, if any, real affect, nothing else needs to be done. Have removed a bunch of them and carefully placed them where they belong, in the recycle bin!

 

[Tools R Us]

...
OP,
Early 80's didn't have VC's from the factory so I wouldn't worry too much about driving without one. VC is probably marginally better for on road use.

The 100 series also has the same transfer, but no VC, it was only used '93-'97. It's biggest benefit is likely; a somewhat effective, over complicated, prone to failure, drive train clunk reducer!

 

[scottryana]

Did you just chuck that up in a lathe and cut it open?

Never counted, but a few more than two.
View attachment 1833282
View attachment 1833283
View attachment 1833284



Kinda works as a weak, briefly acting, limited slip between the two drive shafts.



Without the CDL engaged it's AWD just like any other AWD vehicle. The VC adds a weak, briefly acting, mostly useless, limited slip to the mix. It is a fluid coupling, so like any device of that type, it's best performance was when the fluid was fresh, so in this case, ~20yrs ago. Removing the VC has very little, if any, real affect, nothing else needs to be done. Have removed a bunch of them and carefully placed them where they belong, in the recycle bin!

 

[Tools R Us]

Did you just chuck that up in a lathe and cut it open?

Yep, that one had internal pressure, when it cut through, the cap flew off and caught the owner in the jewels!