Friday, January 3, 2014

Subie R180 Install

Happy New Year

I picked up the parts to do a STI R180 swap a looong time ago
With some time off of work, now was the time do the swap

The first step is to remove the existing diff
Pics of this are pretty boring so I didnt take any
Below is the best way to remove the diff

"1. Remove the rear wheels and tires and place under the car. (I DIDN'T DO THIS)
2. Unbolt driveshaft (4 bolts) and hang out of the way.
3. Unbolt halfshafts (CLOSEST TO DIFF) (8 nuts) and hang out of the way.
4. Unbolt front diff crossmember (4 bolts) and let diff hang off moustache bar (don't worry about the rear LCAs).
5. Put a jack or your chest under the diff.
6. Unbolt the diff from the moustache bar (2 nuts).
7. Slide diff forward onto the jack or your chest."

There is quite a bit of wrangling to be done to get the diff out.
Do yourself a favor and use the jack if it is your 1st time doing this.
Dont try to be he-man and muscle it.
I had to unbolt my exhaust to get some more room to remove.
But the above directions are basic enough to get you where you need to be.

Future home of the new diff

OK here is what you need to do to swap over.

First you need an WRX STI R180 with the Limited Slip type and gear ratio of your choice
2007 STI 3.54 LSD:

Next you need Beta Motorsports Half Shaft adapters.

Wolfcreek Racing currently sells them.

That's it

Start by removing the old diff and salvage the studs from the old half shafts
I hammered mine out with a plastic mallet.
Do not use a steel mallet as you will damage the studs 

Next install the studs you just salvaged into the new Beta Motorsports half shafts
Again use a plastic mallet to "press" them in

Next step is to swap the input flange from your old diff to the new subie diff
The easiest way to do this is with an impact gun and the appropriate socket
Use the impact gun to remove the input shaft bolts and pull the flanges off the diffs

My old datsun flange slipped right off.

The subie flange required some very light persuasion to be removed.

 Put the datsun flange on the subie diff.
Use the impact gun to tighten the bolt.
That's it. Flanges swapped.

Now install ONE of the half shafts
The "subie" half shafts are unlike the datsuns in that they snap in rather than bolt in
Simply hit the shaft with plastic mallet and it will pop in to place

Now fill the diff with fluid through the hole for the other half shaft
Everything I could find says the diff holds 1 liter (1000ml or 1.1 quarts) of fluid
There is a lot of opinions on what diff oil to use for the subie LSDs.
Do your own research and use what you think will work best.
Here's what I decided on:

Now that the diff is full of fluid install the other half shaft.
While I had the diff out I replaced the front crossmember bushing
Easy peasy

Now we are ready to reinstall
If you can, cut a peice of wood to support both ends of the diff on the jack

Position it in place and slide the bolts on the diff cover into the mustache bar and secure

The rest is simply bolting up everything you had previously unbolted.

The diff I got on ebay 2 years ago is junk.
It howls on deceleration like a banshee.
From what I've read the pinion bearings are shot and the thing could grenade at any second


  1. Hi
    I have just fitted some of these into my subie diff but they stick more compared to my old 240Z this normal ???

  2. I'm having some trouble removing the old r180 out of my 240Z, I unbolted the single nut on the bottom of the front mount (right near where it bolts to the drive shaft), and unbolted the 2 nuts on the rear of the diff going through the mustache bar (as well as the 2 bolts holding the mustache bar itself up) but it seems like there is still something more holding the diff in on the front side. I don't know if I can reach all the bolts on the front mount to disconnect the diff from the mount itself, I was hoping to get everything out with the front mount still attached to the diff?
    Please let me know if you can help,