Stub Axle Confusion

[Viva Datsun]

Alright, so I bought an R180 diff out of a 720 4x4 pickup truck that had bolt in stub axles. I originally thought that my 240z stubs would bolt in place of them and all would be well. Well, no, they don't. The new diff has 27 spline stubs that are just a touch bigger diameter but with the big CV shaft flange or something. Okay, so that sounds like standard 280z stubs, right? 27 splines and .080" bigger than the 240 and still a bolt in? So I went to the junkyard today to pull them off the 280z there. Hmm, there's no bolt holding them in... Get em back to the shop and turns out they're 29 spline stubs that use a circlip deal... 

 

SO;

1)Could I use the buttons from my 240z R180 in the 720 R180? Or do they not work that way? The 720 diff (the K diff btw) used bigger stubs so I dunno.

2) What the hell is in the 280z at the junkyard? The car seems in no way racy so I cant imagine that actually being an R230 or something. I'm just stupid confused by that.

 

Here's some pictures to explain, 240z R180, 720 K R180 then I don't even know what they are... left to right

 

Last one's of the 240z and "280z" next to each other

 

Thank you in advance for any help on this. I've done a good amount of research on this but I have no idea what just happened to me...

[Viva Datsun]

And yeah that's my rear hatch, any tips for mass bondo removal would be much appreciated...

Edited August 6, 2015 by Viva Datsun

[NewZed]

Okay, so that sounds like standard 280z stubs, right? 27 splines and .080" bigger than the 240 and still a bolt in? So I went to the junkyard today to pull them off the 280z there. Hmm, there's no bolt holding them in... Get em back to the shop and turns out they're 29 spline stubs that use a circlip deal... 

The last one looks like a typical long nose R200 axle.  They clip in.  The circlip is inside the diff.  Not sure about the spline counts but people get hub axle and diff axle spline counts confused often.

 

Here's a link with some R180 stuff - http://forums.hybridz.org/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/

 

Lots of good stuff in the P&D chapters also - http://www.nicoclub.com/FSM/280z/

[Viva Datsun]

Okay, I must have mixed up my info along the way. I'm still lost on the K R180 though

[RebekahsZ]

I used a truck R180 front diff in my 240z a million years ago. I just put new seals in the axle holes on the diff and put the 240z stubs in the truck diff. Didnt leak-no probs. be careful not to over torque the long bolts. I don't recall the spec, but I recall yanking the threads out of one. It's been more than 20 years. Be careful on your first test drive-you will get in trouble fast with the new-found acceleration that a 4:10 diff provides, especially exiting corners. I have a set of crushed wheels and a broken rear hub and airdam to prove it. From the first test drive! You will also be looking for 5th gear a lot, and 6th and 7th. 4:10s kinda suck on the highway.

[RebekahsZ]

Put the 280z stubs up for sale in the classifieds-they are worth $50-75. They won't fit your R180.

[Viva Datsun]

So the 240 stubs worked in your R180? Mine are a little too small and are 25 spline instead of 27 like the stubs that were in there.

[NewZed]

Maybe that 720 180 is actually a 190.

 

http://forums.nicoclub.com/rear-axle-question-t548684.html

[Viva Datsun]

The H190 they were referring to was the live rear axle in the trucks. I definitely have an R180 "K" model. Everything I read about these diffs said you just have to swap the snap retainer to the bolt in button retainer. The diff I bought already had bolt in stub axles but they were 27 spline ones.

I'm thinking I'm gonna have to swap the side gears from my 3.36 r180 into the new k diff. They should be the same size gears right?

Edited August 6, 2015 by Viva Datsun

[BluDestiny]

I put that same exact diff in my 280zx that came with an R180. The axles just fit in. So it may be because you have the early style r180. 

[jthom5147]

I'm thinking I'm gonna have to swap the side gears from my 3.36 r180 into the new k diff. They should be the same size gears right?

Check your R180s. Most R180K ring gears sets are of a different size than the early R180 (non-k). See this post: http://forums.hybridz.org/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/

 

"In addition to the bolt in axle issues, there is another difference between early and late R180s. Early R180's measure 110mm inside the ring gear. 77 and later model year R180s measure 115mm inside the ring gear. This minor change means that the ring and pinions won't swap between the early and later models. If you have an early diff you must use an early carrier, and if you have the later diff you must use a later carrier. It is possible to use a early carrier on a later ring gear with a spacer, but that is outside the scope of this thread."

 

 

 

So the 240 stubs worked in your R180? Mine are a little too small and are 25 spline instead of 27 like the stubs that were in there.

 

You counted the splines on your R180 diff side flanges and they were 25? I thought all R180 center gears were 27 spline, and R160s from 510s etc were 25 spline.  Or are you confusing the stub axles (wheels bolt to the stub axle) which are 25 splines on the 240Z?

[Viva Datsun]

I'm talking about swapping the spider gears that the output flanges spline into if that makes sense. I guess I've been referring to the output flanges on the diff as Stub axles

Edited August 6, 2015 by Viva Datsun

[NewZed]

Maybe your "later" R180 axle is too later.  That's a CV joint bolt pattern.  Could be a viscous diff, with CV's.  Just a thought.  Whatever they are, it just looks like you've assumed that you have certain parts, but you really don't have what you thought you had.  

 

If you set the R200 (280Z) axles, and the 720 truck axles aside and started over, you'd probably get to where you want to be.

 

[jthom5147]

I've never heard of an R180 VLSD, especially one with bolt-in stub shafts. I can take a picture of my 280z r200 stubs and my n/a z32 vlsd stubs next to each other and you can see the length difference required in order to engage the vlsd unit. It doesn't look like what is originally posted.

 

The diameter difference is weird. To confirm, the 720 and 240 stubs are both 27 spline, and the splines on the 720 stubs are 0.080" larger diameter?

 

Can't tell accurately from the picture as visually they look the same dimensions.

[NewZed]

To be clear, I was just making things up, I only know hwat I've read on the internet re R180's..  I'm only interested because it's supposed to be easy.  It seems that either the 240Z R180 isn't stock, or the 720 R180 isn't stock.  That seems to be the crux of the situation.  The R200 axles shouldn't even be here.

 

The difference in the shaft width to the spline shaft width (the step), is obvious in the pictures.  Some Googling of 240Z R180 axles, and 720 axles should tell which is stock, and which is not.

[jthom5147]

I brought up the R200 vlsd stubs at a length reference, not in relation to the diameters or spline counts. 

[jthom5147]

I did find this thread: http://community.ratsun.net/topic/55608-r160-to-r180-510/

 

See image 1 at post 8. 

[NewZed]

My R200 comment was directed at Viva.  He got a 280Z with an R200 instead of an R180.

[NewZed]

I did find this thread: http://community.ratsun.net/topic/55608-r160-to-r180-510/

 

See image 1 at post 8. 

That's a good one.  Look at the step from the splines to the main shaft, on the 3x2 bolt pattern shafts.  Viva's have a smaller step.  Bigger splined shaft.  But all of those in your picture look the same.

 

Anyway, good to learn that there are pitfalls everywhere.  Take your calipers to the wrecking yard.

[jthom5147]

Compare the 720 stub in the linked picture compared to Viva's.

 

Viva's has next to no step down in his picture. Viva's 240z stub has a step down. Viva's 240z step down looks the same to me as the datsun stub in the link AND the 720 stub in the link.

 

I.e. the 720 stubs in the link and from viva don't look similar.