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80 series diff fitted into 73 series!!!!!

Discussion in '70-Series Tech' started by Bluey, Mar 20, 2004.

  1. Bluey

    Bluey

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    first off, must say that this very cool site :D

    i have a '85 bj73 cruiser, and love it heaps. standard 3b no turbo at this stage, stock springs with 33" bfg muddies, and afaik standard diff ratios. so i'm after some info, have oppurtunity to buy diff but not sure if will fit or how much modifying needed....

    from seller
    and
    so, is this right. can i just bolt in and most i'm looking at is to re-drill flange on diff and then i have locker :D
     
  2. beanz2

    beanz2 Moderator

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    will this diff fit my bj73?

    It should fit, even the driveshaft should bolt on to the pinion flange.

    Dave
     
  3. roscoFJ73

    roscoFJ73

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    Re:will this diff fit my bj73?

    Hi blue ,dave. I think your right blue about the flange size bluey.The 1HZ t/case has the larger flange.You can replace yours with a larger flange, or there is also a flange available that has 2 sets of bolt patterns on it.I think it got bigger when the 80 series 1st appeared
    I was talking to a wrecker the other day and he reckons one of his customers found that his later model t/case turns the front diff the opposite way.I dont know if this is bullshit or if it will effect me.Im not worried as I have 2 good t/cases,an 88 and a 96.
    I was also looking at some diffs on a HJ75 the other day and Im sure the pinion was at the top and had different reinforcing fins on the diff carrier.On my 73 diffs the pinion is sort of lower centre .The pics in my Gregories 507 and 513 manuals also show 2 different looking diff carriers.Bolt pattern looks the same so the pinion position probably wont make any difference.The higher pinion would be better for future lifts
     
  4. bad_religion_au

    bad_religion_au

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    Re:will this diff fit my bj73?

    what year hj75? i think they went to the high pinion "smaller" front diff (similar to the minitruck/ hilux) so could be the smaller/ weaker diff than 40 and 60 series cruisers, which use the same diff as the rear axles.
     
  5. Radd Cruisers

    Radd Cruisers

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    will this diff fit my bj73?

    Sounds doable............

    Welcome to the otherside Bluey, you a regular on the Outer Limits?

    I have not seen BJ over on this side lately or even on the Pirates, were is he hiding out.

    Good luck with the pending swap.

    Rob
     
  6. bad_religion_au

    bad_religion_au

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    Re:will this diff fit my bj73?

    Bj's been on outer limits.
     
  7. roscoFJ73

    roscoFJ73

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    Re:will this diff fit my bj73?

    Im not sure of the year of the HJ 75,it had the compliance plates removed but they looked the same as HZJ75 diffs.Its possible the 75 traytops for the mining industry got the high pinion diff while the 73/74 series of the same year kept the low pinion .Just a guess. The I dont think they started using the Hilux diff until the 78/79/100 series.
     
  8. beanz2

    beanz2 Moderator

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    will this diff fit my bj73?

    Hmmm, it seems to me the '85 BJ73 and the 80 series shares the same pinion flange ???

    I've always thought the high pinion diff is not available in the J7 line until the HZJ78/79. Anyway, while moving some axles today, I did a double take at one of the diffs as it appeared to be high pinion. It turned out that the axle was upside down. I didn't notice the drain plug was on the top :)

    The reinforcing fins on the diffs do differ on the year and whether the unit is a locking unit. The thick rib (I suspect this is for the oil channel to lubricate the pinion bearing) is at 6 o'clock position on the pre-90 and locking diff units. On the 1990 and up 9.25" crown gear units they are at 4 o'clock.

    Dave
     
  9. roscoFJ73

    roscoFJ73

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    will this diff fit my bj73?

    The reinforcing on my 73 diffs all run horizontal and vertical .The diffs in my 1HZ manual and the ones I saw on the HJ75 had the fins radiating out from a central point.
    It is possible the diffs off the donor had been added later by the PO.
    The flanges in the pics in my 2 manuals also seem to have differing sizes although the view is not clear.I will be investigating further tomorrow
     
  10. roscoFJ73

    roscoFJ73

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    Re:will this diff fit my bj73?

    I reread your post Dave and I think we are talking about the same thing so maybe the diffs are a transplant in the HJ75.
     
  11. Bluey

    Bluey

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    will this diff fit my bj73?

    cheers, thanks for the replies. i'm definately getting this now. managed to score few bits n pieces on net lately, waiting on tube bar to top it all off :D


    [quote author=Radd Cruisers link=board=21;threadid=13429;start=msg124507#msg124507 date=1079840867]
    Welcome to the otherside Bluey, you a regular on the Outer Limits?

    Good luck with the pending swap.

    Rob
    [/quote]

    yeah, been on outerlimits for couple of months now. use same username as here. saves me confusion if nothing else :D
     
  12. bad_religion_au

    bad_religion_au

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    Re:will this diff fit my bj73?

    "Hilux diff until the 78/79/100 series."

    my mates 92 hj75 tray got high pinion hilux diffs... i know cause he keeps bitching when he busts them
     
  13. beanz2

    beanz2 Moderator

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    will this diff fit my bj73?

    What was I thinking? :-[ You are right, the high pinion started in 1990 in the J7 series. They aren't exactly hilux diffs though, as Hiluxes got standard pinions and standard, not reverse-cut, crown/ring gears.

    Dave
     
  14. bad_religion_au

    bad_religion_au

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    Re:will this diff fit my bj73?

    hilux ring gear size or something... same as the 80 series i believe. i just call em hilux diffs to p!ss this friend off
     
  15. beanz2

    beanz2 Moderator

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    Re:will this diff fit my bj73?

    [quote author=roscoFJ73 link=board=21;threadid=13429;start=msg124603#msg124603 date=1079855504]
    I reread your post Dave and I think we are talking about the same thing so maybe the diffs are a transplant in the HJ75.
    [/quote]

    I know what you mean by the rib patterns on the diffs. Let me see if I can snap some pics...

    Here is one that has the 80 series diff rib pattern. This unit is a factory limited slip but the open diff looks just like it:

    Hmmm, can't get the pic to attach...
     
  16. beanz2

    beanz2 Moderator

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    will this diff fit my bj73?

    LSD diff:
     
  17. beanz2

    beanz2 Moderator

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    will this diff fit my bj73?

    Here is an electric locker unit. Not taken from the same angle but you can appreciate the directions of the ribs.
     
  18. beanz2

    beanz2 Moderator

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    Re:will this diff fit my bj73?

    trying to find one pic taken of a pre-90 diff side by side with a cable locker...
     
  19. Bluey

    Bluey

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    so, the diff arrived yesterday, what i got (and didnt explained properbly) was full diff carrier from pinion flange thru to ring gear. backlash set up, detroit installed, solid pinion bearing spacer machined & fitted. quickly did trial fit of driveshaft to pinion flange and no problems there. then drained oil, today remove axles and removed existing diff carrier and bolted in new one with locker. no modifying needed at all, just bolted up :D. put in new oil and we are away again.

    probably took me about 3 hours, never done this before. took round same time to undo oil filler nut :mad: :mad:

    so tip for anyone else, remove oil filler nut first, then drain nut. if filler nut wont come off, at least you can still drive the car :mad:



    anyway, car now drives like it is on rails, feels awesome. have noticed no noise from the locker, slight on off power tight corners. cant wait to test it out in the bush :D

    took couple of pics, will post up if interested. (none of install stage, didnt want to ruin dad's digi)
     
  20. roscoFJ73

    roscoFJ73

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    Great news bluey ,suspension next??