Z31 driveshaft and other driveline compatability information


  • Z31 driveshaft and other driveline compatability information

    I figured this was needed because of the shear number of driveshaft and driveline part related questions I answer for people. All of my knowledge comes from working on Z31's so if I have something wrong, please feel free to correct me and we will make revisions over time!

    These are the dimensions of an early 2 seater manual turbo (T5) driveshaft:



    All manual transmissions are the same length, so hence all manual driveshafts for two seat cars are also the same length.

    Transmissions each have their own unique slip-yoke on the driveshaft, and length for their application:
    ~Automatic
    ~NA manual
    ~Turbo manual (T5)
    ~87+ turbo manual (90A)
    ~Automatic, 2+2
    ~NA Manual, 2+2

    In addition, the joints are not the same size in the N/A and turbo (at least manual) shafts; turbos are bigger so you cannot simply swap yokes or diff flanges on the shaft. On a side note I have only seen replacement-type joints listed for the turbo driveshaft's joint sizes, not the NA. It's easy to see from this information that if you want to put a turbo manual transmission in a 2+2 car, you will need to have a standard turbo driveshaft lengthened (re-tubed) or a custom unit made

    There are two diff flanges:
    Early (rectangle)
    Late all 87+ (round/square bolt pattern)

    You can swap the differential companion flange on the diff relatively easily with a steering wheel puller. Be sure to re-torque the pinion nut after swapping the flange!

    All Z31 differentials will interchange and spline to all Z31 halfshafts; the only notable exception being the SS viscous LSD and half-shafts which are unique.

    The half-shafts
    themselves are only different between turbo and non-turbo models. Aside for having a different type of joint, Nissan also chose to change the style of flange on the outboard flange that the half-shaft bolts on to. This flange is known as the axle stub companion flange because it splines directly onto the axle stub. NA cars have 6 bolts, while turbo have 4:



    If you are swapping turbo halfshafts into an NA car, you will need to obtain the correct companion flanges for not only the correct model (turbo/NA) but also the correct year group, as they were changed for the 87-89 cars.

    The axle stubs
    appear to be the weakest link in the otherwise very strong rear end. http://www.modern-motorsports.com makes upgraded units, but they are rather expensive.

  • #2
    I can measure the 30a 2-seat and 71c 2+2 for you at some point....

  • #3
    Good info, thanks.

  • #4
    Axle Stubs and Companion Flanges have always haunted me as I have nevewr had the luxury of changing them on the z31's untill today. I read that the book time for the changing of the bearings was 2.8hrs and Based on everyones responses, complaints, etc..over there at z31.com, I thought I was in for a real PITA.

    **With the proper tools, these things pop right apart, "piece-a-cake". (I love how the FSM goes through the complete steps..hahah, yeah, right!)

    Here was my method that worked real well:

    The biggest thing is popping the companion flange off first in the direction of the differential after impacting the stub axle nut off with a 30mm socket. I used a decent slide hammer to do this then pulled the axle stub out the opposing way with the same type of tool.
    It actually only took a couple hours to do, start to finish.
    **The inner wheel bearing and grease seal came out and went back in with the same slide hammer method. Quick and Easy.
    The next issue is the outer bearing…getting it off the axle stub and then back on.
    **This requires a large bearing seperator and a press**

    ^^Half the battle is having the proper tools and the proper instruction^^
    >>>>I hope everyone else has as good of luck doing these as I did
    I am here to help…

  • #5

  • #6
    Jason84NA2T wrote:
    If you are swapping turbo halfshafts into an NA car, you will need to obtain the correct companion flanges for not only the correct model (turbo/NA) but also the correct year group, as they were changed for the 87-89 cars.
    Companion flanges are different between 84-86 and 87-89? Are you talking about 4/87+ (W series) cars? Wow, I was planning on swapping my 84T flanges into my early (non-W) 87 NA for my home-made halfshafts. So according to this, they won't fit? Whats different between them? I have never heard this before…
    "produce first.talk second."

  • #7
    excellent… so distilled this means
    84-86 - rectangular flange
    87-89 - square flange
    2 seater - 34" length
    2+2 - 42" length
    71c yolk - 1.38" diameter
    30a yolk - 1.655" diameter
    90a (t5) yolk - 1.5" diameter

  • #8
    I will add all of this information to the first post. Thanks guys!

  • #9
    Am i reading correctly that 87 halfshafts do not swap into 86na car, even with the proper 87 flanges?
    Praying....

  • #10
    1SickZ wrote: Am i reading correctly that 87 halfshafts do not swap into 86na car, even with the proper 87 flanges?
    the front end is tranny specific, the rear end is year specific, combine

  • #11
    so to clarify something for myself, if I'm going to swap an 71C into an 88 Turbo auto, I need the differential flange and drive shaft and thats all?

  • #12
    SpeedyZ wrote: so to clarify something for myself, if I'm going to swap an 71C into an 88 Turbo auto, I need the differential flange and drive shaft and thats all?
    read the chart again.... you may not need the flange

  • #13
    As long as were talking driveline compatibility:

    If swapping a BW T5 into your 87-89, or if swapping a 30A into your 84-86, The transmission mount will need to be modified. The holes need to be slotted in the mount and/or the transmission to allow alignment with the tunnels mounting points.
    "produce first.talk second."

  • #14
    Like Mike said, "as long as were talking driveline compatibility:"

    You cannot hybrid z31 half shafts with 90-96 q45 half shafts simply by pulling the two apart and mixing and matching pieces. If you could it would enable you to run the beefier Q45 diff in the z31. But you cant. You also cant just drop in the Q45 diff and half shafts. The shafts are different lengths. It is not impossible but requires fabrication. I am going to see if the carriers will swap over. If they do without a problem, then all that is required is cutting half shafts, shortening, sleeving them and welding them back together.

    EDIT:

    The carriers do swap over just fine, so like I said all you have to do is shorten the half shafts and splice the z31 and the Q45 half shafts together and weld. Or you can have a custom axle made that allows the Q45 CV on one side and the z31 CV on the other side. Each one of those axles cost's approximately $200 a piece to have made. Yes you need two of them.
    85 Z31 6.0 LSX turbo 766whp/792wtq
    04 GTO, LS6, big cam, porting, N20… underway for summertime daily driver.

  • #15
    Is there a difference between the left and right side axles on an 86na. im trying to buy new axles, autozone sent me one correct one, the other one they sent me was for some type of front wheel drive car. so they say it was boxed wrong and they send me another, which of course is the same wrong one they sent me in the first place. I know there are different part numbers, but maybe ::crosses fingers:: they are the same so i can tell these idiots to just send me another one of the axles i got that was actually right.
    Ride it like you stole it…
    1986 300zx NA2T - CM 3" turbo back, Pathy 3.0 Engine, Custom cold air intake, 255lph Walboro, T3 turbo, 90 shot of nitrous, 30A trans, 88t LSD, Poly everywhere, SS brakelines. 288whp 336wtq
    2001 YZF600 - Sold for Nitrous and Exhaust Upgrade…
    1993 Toyota Corolla - The invincible daily driver, off to greener pastures.
    2002 Nissan Maxima SE - New daily driver