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78 280z automatic diff side axles


hansonsaid

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i'm a longtime reader and thankfully every question i've had thus far has already been asked and answered on this site.  i've struggled to find anything definitive on this topic, however.

 

after refreshing all the suspension on my 1978 automatic 280z i've been left with a vibration during acceleration over 40mph.  all my work has been quadruple-checked my myself and my brother(lemans crew chief) and the only part that has been affected but not changed are the halfshafts.  the car was lowered less than two inches so i didn't expect cv axles to be a necessary upgrade, but every 40 y/o car is a unique case and all the symptoms point to binding u-joints.

 

even if it doesn't solve the vibration, i ordered the kit made by ermish racing(after double checking that it would be compatible with my r180 diff) and now that it has arrived i find my diff to be different from any photos i've seen.  the diff stubs/side axles resemble the slip yoke at the back of a transmission, not the typical flanged style i've seen in everyone else's photos.  i know there's not a lot of commonly available info out there regarding the differences of the automatic driveline, but i haven't found a single reference to this particular difference.

 

can anyone guide me to which particular diff side/stub axles will fit in my particular diff?  oem or aftermarket options are both fine, my goal is to utilize the cv kit i now own without going so far as installing a new differential.

 

thanks!

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You might give your u-joints a good look.  It's hard to tell that they're loose without really prying on them.  Stick a screwdriver between the yokes and reef on it with a bright light to see movement. 

 

Why do you think that your R180 halfshafts look different from the ones in the FSM?  You can see the bolt head.  Maybe you've been looking at the Subaru R180 pictures.

 

 

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I think that you just need R180 bolt-in axle flanges, instead of bolt-in half-shafts.  I don't really understand which cars have which.  Your thread title is misleading, your problem has nothing to do with "automatic" besides the fact that they came with R180's.

 

jmortensen's thread shows what you want yours to end up looking like.  Clip in versus bolt-in.  Don't know how to get there.  He seems to imply that the older R180's used the bolt-in flanged axle.  So maybe you just need to find an older R180 and take the bolt-in flanged stub axles.

 

http://forums.hybridz.org/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/

 

John Coffey's work implies that the early R180's had the flange you want also.  I think that you just need an old R180.

 

http://forums.hybridz.org/index.php/topic/78123-subaru-wrx-sti-r180-side-axles

 

 

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i see now that there is a difference between the early and later r180 diff stubs.  NewZed you are exactly right, i need bolt in axle flanges from the early r180 to replace the bolt in half shafts my 78 has.

 

my reference to the automatic-spec of my car was to make sure everyone understood what i was working with, i didn't want to send HybridZ on a wild goose chase, and i'm happy to have shown the semi-shallow depth of my knowledge since it led to me easily learning something new(difference in spec of early vs late r180).

 

the ermish kit is exactly as pictured on the slideshow of that link, it's very similar to the driveshaftshop kit and seems to be 100% bolt in with very clear instructions included(unlike reports of the dss kit).  my particular issue with fitment was my lack of knowledge of the differences between the early and late r180 diff stubs.  when i have all the parts necessary i'll make some comments on the install and driving experience of the ermish kit, right now all i can say is troy ermish has fast communication and shipping of what seems to be a solid product.

 

thanks for the help NewZed, much appreciated!

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Good luck.  The 240Z R180 pictures in the FSM's show the flanged axle.  Looks like Nissan was shifting to the complete one piece halfshaft, similar to the ZX CV halfshafts, for the 280Z's.  Learned something new.

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  • 10 months later...

As a matter of fact, the automatic transmission has everything to do with this axle discrepancy. According to the factory parts listings, the half-shafts with u-joint flanges that bolt to the differential stubs were used on manual transmission cars, while automatic cars got "Assy-Yoke Side." In the attached photos, the freshly-rebuilt half-shaft (Assy-Drive Shaft in Datsun-talk) is a manual transmission version, while the rusty dirty ones are for automatics.

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