HF2A vs HF2AV (1 Viewer)

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Can someone give me a breakdown of these two transfer cases? I've done a bit of searching & research and not found much. The HF2AV is almost always simply referred to as an HF2A which makes it doubly confusing. Obviously the HF2AV has the viscous coupler making it the full time 4WD version in ... all American 80 Series?

If the non-VC HF2A was never sent to America then that clears up a bit of confusion. Or at least why there's very little info out there on them.

But leaves me with one more question: Would that make the non-VC HF2A essentially the same as a Part-Time 4WD modified HF2AV? Or are there other differences as well? Is gearing the same?

My 1990 JDM parts rig has an H151 and HF2A (non-VC) and I'm debating Pros & Cons of running it on my 1995 80. In part to not have to make custom driveshafts...

Thanks!
 

TurboDennis

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You're confused about what VC is.

Both HF2AV and HF2A came on American 80's depending on the year (later years got the VC case). Both are full time cases. Gearing is the same. Both cases have a differential inside (part time HF1A case does not). The only difference is that one case has the VC and the other one doesnt. VC is a device designed to equalize the torque going to both axles (essentially making the differential inside the case a "limited slip" unit). When someone converts the HF2-series case to part time, they remove/disable the differential inside. Viscous coupler has nothing to do with it.
 
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Ah. Ok. I had read several references to the non-VC case as being “open” and that was part of what confused me about it. That clears that up. “Open” as in without LS function of the VC. Got it.

So are there ANY inherent advantages to the non-VC case? Is the VC the weak point at all making the earlier version more durable? Is less general traction during normal driving considered a benefit in any scenarios?
 

TurboDennis

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Ah. Ok. I had read several references to the non-VC case as being “open” and that was part of what confused me about it. That clears that up. “Open” as in without LS.

So are there ANY inherent advantages to the non-VC case? Is the VC the weak point at all making the earlier version more durable? Is less general traction during normal driving considered a benefit in any scenarios?

Both cases are technically "open" (when the diff lock is not engaged). The VC will still allow the axles to turn at different speeds. It just limits/reduces their ability to do so excessively.

As for advantages of the non-VC case.. The only REAL advantage that i can think of is the ability to run a mismatched spare tire (doing so with the VC will fry it).
VC is not really known to fail on its own without the owner causing it (by running mismatched tires, for example).
There is no situation where less traction or excessive spinning of one axle is desirable.
The advantages of the VC far outweigh the disadvantages, IMO. Not only it provides better traction in slippery conditions, but it also acts as a shock absorber in the drivetrain, reducing noises and wear.
 
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So I believe I'm having some t case issues. 93 hdj81 jdm with 1hdt auto trans a343f I believe. It started with a vibration between 80-100kph and NOT under a load, so basically when I would let off the gas a little. As soon as I gave it a tiny bit more throttle it would go away, or if I would let off throttle a little more it would go away. The other day I noticed for the first time my t case is leaking. Not from output shafts but appears to be center of case where they're split. Leak is coming from bottom of case as it is all that's wet. Has the gasket just failed? Side note, I do have a tiny bit of play in rear drives shaft. Not in u joints but where it enters t case (output shaft bearing). Again, it's not leaking there though. Any ideas? Also, what t case do I have? Hf2a or hf2av?
 

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