Transfer Case Differences on 80 Series (3 Viewers)

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BarnFab

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So I never paid much attention but I always thought that the majority of the 80 Series Transfer Cases where the same but just found that not to be the case so am looking for some info.

I have two Cruisers sitting here one is an Auto FJZ80 from 1993 and the other is a Manual HDJ80 from 1993.

The manual one has a significant;y shorted rear housing on the T-Case and a PTO Cover plate, the Auto has the usual long housing and blanked PTO area.

Can anyone shed any light on what the differences are ?

maybe @cruiseroutfit since the gears I got off him are heading into them and hopefully they are the same .

Is one better than the other ?
 
Your 1993 FZJ80 case is HF2AV. It has a viscous coupler in the rear housing, that's why its longer.

The HDJ80 can have 3 different cases depending on the market where it came from. Most likely either the part time HF1A (in which case the gears you bought will not be compatible), or the HF2A, which is the same case as the HF2AV, but without the viscous coupler. PTO access plate makes no difference in your case (other than the obvious fact that you wont be able to bolt the PTO to the case without it).

Which one is better will depend on how you're using the truck. I personally think the HF2AV is the best case, but some people have a different opinion.
 
Last edited:
TurboDennis said:
Your 1993 FZJ80 case is HF2AV. It has a viscous coupler in the rear housing, that's why its longer.

The HDJ80 can have 3 different cases depending on the market where it came from. Most likely either the part time HF1A (in which case the gears you bought will not be compatible), or the HF2A, which is the same case as the HF2AV, but without the viscous coupler. PTO access plate makes no difference in your case (other than the obvious fact that you wont be able to bolt the PTO to the case without it).

Which one is better will depend on how you're using the truck. I personally think the HF2AV is the best case, but some people have a different opinion.
Click to expand...

Ok so the HDJ80 came from France and it doesn't have FWH on the front and has a center diff lock switch.

How does it work in AWD without the viscous coupling I thought that was what allowed it to drive around in AWD and not bind ?

Based on your description I am guessing I have the HF2A
 
Definitely HF2A then.

Differential in the transfer case is what allows you to drive in 4WD without binding. Both HF2A and AV have it. HF1A does not.
Viscous coupler is a device designed to equalize the torque going to both axles in the event where one axle loses traction. Essentially making the differential inside a "limited slip" unit .
 
Sort of a continuation of this, but can you take an HF2A and put the housing for the VC on it and run it in a vehicle that originally had an HF2AV so as to not need driveshaft mods?
 
So if the HF2A does not have a viscous coupling in it I presume it sends the same torque to both axles, if this is the case then how does it not bind on the sealed roads like a split case if it is in 4WD ?

The Manual setup has a shorter front drive shaft and a much longer rear drive shaft being manual is shorter than the auto and it also seems to have the HF2A which is several inches shorter than the HF2AV further lengthens the drive shaft in the rear.

I am guessing the only difference between the HF2AV and the HF2A is in the rear case so both fronts appear to be the same meaning you could swap them over .


mjosoba said:
Sort of a continuation of this, but can you take an HF2A and put the housing for the VC on it and run it in a vehicle that originally had an HF2AV so as to not need driveshaft mods?
Click to expand...

I am going to say NO since the Manual transmission is shorter than the Auto even in the T-Case was the longer HF2AV the front dive shaft would be shorter and the rear would be longer since the transmission is shorter it all sits further forward.

It does look like it will bolt together though and the front half of the housing is the same on both
 
So this is the HF2A on the Manual Trans

2a6cec94afce4700134dd3aa9e335e84b51d05af-1.jpg

This is the HF2AV on the Auto Trans

5e0451e20f3a3d811b04d4b96eead8d4fdb772a0-1.jpg
 
No, the differential is open so it doesn’t send the same amount front to back, that only happens when the center diff lock is engaged. The viscous coupler basically is a shock absorber for the system, at least that’s how it seems to me. The transfer case works fine without it.
 
BarnFab said:
So if the HF2A does not have a viscous coupling in it I presume it sends the same torque to both axles, if this is the case then how does it not bind on the sealed roads like a split case if it is in 4WD ?
Click to expand...

It works the same as any open differential. It sends power to the shaft with least resistance. If your from wheels are on snow and spinning, and rear on asphalt, it will send power to the front wheels.
With open centre diff, open front and rear diffs, you're essential in a one wheel drive.

The t- case locks the centre differential when you engage low range giving equal torque to front and rear shafts
 
Is there anywhere that has a plate on the transfer case that tells you which kind it is because I have an RHD HDJ 81 from September 1992 and it has an A442F with the four solenoids transmission and I am curious which version mine is as well.
 
84lumberman said:
Is there anywhere that has a plate on the transfer case that tells you which kind it is because I have an RHD HDJ 81 from September 1992 and it has an A442F with the four solenoids transmission and I am curious which version mine is as well.
Click to expand...

Being hdj81, that transfer case will also most likely have synchro rings on the high range gears. USA 80 didn't.
Synchros mean you can shift to high range while on the fly . . . Er, on the crawl
 
That's why I was trying to find the exact transfer case or if there's some sort of distinguishing plate on it so I know exactly which one it is. I will either have to get another transfer case or find some sort of rebuild kit for the exact model that I have. I don't want to have to pull it out and then find out and not have the parts. I would prefer to have a rebuild kit or another transfer case ready to go in. The problem is that whenever I shift into gear it grinds and sounds like something Metal has fallen out inside and I originally thought it was my transmission but when I put my transfer case in neutral or low it works perfectly fine but just not in high so it must be a transfer case problem
 
84lumberman said:
That's why I was trying to find the exact transfer case or if there's some sort of distinguishing plate on it so I know exactly which one it is. I will either have to get another transfer case or find some sort of rebuild kit for the exact model that I have. I don't want to have to pull it out and then find out and not have the parts. I would prefer to have a rebuild kit or another transfer case ready to go in. The problem is that whenever I shift into gear it grinds and sounds like something Metal has fallen out inside and I originally thought it was my transmission but when I put my transfer case in neutral or low it works perfectly fine but just not in high so it must be a transfer case problem
Click to expand...

Grinds while you are changing gears? Or after?
Auto or manual transmission?
 
84lumberman said:
The problem is that whenever I shift into gear it grinds and sounds like something Metal has fallen out inside and I originally thought it was my transmission but when I put my transfer case in neutral or low it works perfectly fine but just not in high so it must be a transfer case problem
Click to expand...
Not necessarily, have you eliminated the front drive flanges being stripped? Being an 'import' I'm not sure about the mechanicals on your truck, but the US spec trucks can have stripped drive flanges, and the problem is masked in low range when the center diff is locked. Similar to what you are describing.
 
-Spike- said:
Not necessarily, have you eliminated the front drive flanges being stripped? Being an 'import' I'm not sure about the mechanicals on your truck, but the US spec trucks can have stripped drive flanges, and the problem is masked in low range when the center diff is locked. Similar to what you are describing.
Click to expand...

This was an issue for all markets prior to '94 (late '93).
 
I think @-Spike- may have picked it

Check your drive flanges on the front hubs. The splines on the birfs and the drive flanges wears out, particularly on early models.

They will wear out to the point we the splines will strip, and you'll lose drive.

When you shift to low range, this locks the centre diff in the transfer case, so the rear wheels will give you drive.
In high range, centre diff is open, so all drive will go to the wheel with least resistance. If a flange has stripped, drive will go there.
If you have a CDL button, try locking the transfer case when in high range, see if you get drive then?
 
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