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Transfer Case Reduction Box vs. Front & Rear Gears

Discussion in '80-Series Tech' started by Beast II, Feb 4, 2004.

  1. Beast II

    Beast II

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    I'm basically "gear challenged" and don't quite understand the difference between a transfer case reduction box and lower front and rear gears for a FZJ80.

    Here's the link to the transfer case reduction box: http://www.marlincrawler.com/dual_toybox.html

    Since the FZJ80 is always in 4 wheel drive, wouldn't the transfer case reduction box be like having a super low range lever alongside the low range and high range levers ?

    What's the difference ?
     
  2. PHAEDRUS

    PHAEDRUS

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    Beast,
    until they make one for the a440f the a442f or the a343 on your truck I dont think these will help you much. marks adapters in oz was working on one for the 80s but from what I recall it is not ready yet, ask dan kunz he was spearheading that info gathering.
    as to the difference the net result is the same when off road. on road there is a night and day difference. the diff gear is constant. not adjustable so you take your 4.11 gear ratios and make them 4.56 ratios. this will effectively lower the output to the wheels. this will effect your top end on the highway and effectively lower it. not that this is a bad thing. on that unit the main range was 1:1 so no net effect on the wheels when not engaged. it sounds cool and I was salivating as well until I read what transmissions it mates to.
    I could be wrong here but I dont think so.
    Dave
     
  3. Chris_Geiger

    Chris_Geiger

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    The ToyBox we sell here at Marlin's does not currenty fit on 80 series trannys. We have looked at doing this but it would be a lot of work including notching or replacing the gas tank.
     
  4. FJ809496TLC

    FJ809496TLC 80 series addict GOLD Star

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    I thought Advance Adapter have crawl box for 80s cruiser already? Arctic Trucks have been using double low on some of their 80s years ago. When you switch to a bigger diameter tires, you need to change your ring and pinion gears to stay with factory ratio or close to it. Randy's ring & pinion has a chart that tells you the RPM for a certain diameter and ratio and so on. The lower the crawl ratio is, the better for climbing. :)
     
  5. landtank

    landtank SILVER Star

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    Automatics don't need ultra low gearing as do manuals. This is do to the fact that the torque converter acts like a multiplier and adds gear reduction when it's slipping. I run 315 w/4.88 gears. This is an overall change in gearing of 8%. The truck drives like it is 1000lbs lighter. Gas mileage hasn't changed do to the fact that the truck moves easier now. The rpms are higher but not so that I can't cruise at 85 contently. And towing is also easier. Regearing the diffs will benefit all aspects of driving the truck.
     
  6. Big_Moose

    Big_Moose

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    [quote author=The Beast II link=board=2;threadid=11034;start=msg99286#msg99286 date=1075936275]
    I'm basically "gear challenged" and don't quite understand the difference between a transfer case reduction box and lower front and rear gears for a FZJ80.[/quote]

    A transfercase reduction box is the samething as "dual transfercases", or it is just another transfercase inline - either before or after the Original transfercase. So this would give you the option of low range using the orginal TC, low range of the added second [transfer case reduction box] case, or low-low range with both cases engaged.

    Lower gears for the front & rear??, assume you mean the ring & pinion? (higher numerical) lower geared ring/pinion is used with larger tires / bringing the engine power band / rpms back to the normal operating curve.

    As Chris mentions, Marlins toybox is not produced for the 80's, its mainly for the H41/42, SM420, SM465, TH350, etc. tranny's used in other landcruisers / forerunnere / mini's, etc.

    The added second transfercase would not effect the "fulltime 4WD" system, since it would be maintained in high (1:1) range until engaged. However, the major problem is that the second transfer case would have to mount in front of the "Fulltime" transfercase to avoid gear windup / binding, etc. Then you have to consider clearance around the floor pan, gas tank, body lift, placement of second case shifter - may have to use pneumatic / electrical / cable actuation, etc.

    Marks in Australia has a crawler geared transfer case product that mounts on the back of the transfercase, and uses the transmission output shaft after it passes through the input gear of the transfercase.

    Joe :beer: