SUBARU R180 DIFFERENTIAL MAKEOVER
When it comes to Datsun differential upgrades, modifications etc. Subaru’s R180 is no stranger. This is a very popular (direct bolt-in) for 510 coupe’s and sedans (wagons came with a solid rear axle).
My first experience with this differential was in my RWD Subaru GC8, which had a 2006 STi R180. The difference between the popular 2004-2005 STi R180 and the 2006 STi R180 is simply the gear ratio. 04-05 had 3.90 and 2006 had 3.54. In 2007 they got rid of the CLSD and went with a Torsen.
This particular differential was purchased through a friend of mine I met through the RWD Subaru community, J.R. Conner. He assured me that this diff was recently rebuilt by a local shop and that the center section was replaced with a Cusco 2-Way LSD. Though the internals were brand new or had little use; the exterior needed a makeover.
What is the focal point of the differential? Well, the cover of course! Originally I was going to use an OEM cover with a cerakote finish, but changed my mind to revisit a company I’ve had a great experience with: Machined Speed. Matt over at Machined Speed CNC’s these billet R180 covers out of 6061 aircraft aluminum and finishes them in type 3 anodize. They are made to still mate to the OEM Subaru gasket and vent. One of the first aftermarket parts I bought for this car was Matt’s CNC’d mustache bar for the R180 so to finally get my hands on his diff cover seems only fitting.
I wanted to give a solid attempt at cleaning any surface grease, dirt, grime etc. before putting down Eastwood’s primer and then following it up with Eastwood’s Chassis Black. This car needs to have sleek and sophisticated color features that all coordinate together. Currently the crossmember and its control arms are powder coated satin black…this will be somewhat the same ;).
I wasn’t just going to stop at some fresh paint…oh no. If we were going to overhaul this diff then we were going to go all of the way. One of the original bearing retainers had a broken ear so I purchased new OEM retainers w/ yellow zinc hardware to add some contrast. In addition to the retainers, I also bought zinc’d hardware for mounting the differential cover to the housing.
Original Subaru R180 diff covers came with 2 studs protruding out to attach to the mustache bar, which is then mounted to the chassis. For ease of removal/install I will not be using studs, but rather these nice 12pt ARP bolts.
Also, the original diff had 1 drain plug and 1 fill that had an ugly temp sensor integrated, both of which are now replaced with (2) -8 ORB Phenix Industries plugs. When Matt machined these covers he used ORB threads instead of NPT for decreased chances of leaking. Phenix Industries has been a partner of ours since 2015 and I stand behind their product and customer service 100%. If you have any needs of plumbing, AN fittings, hose etc. they should be your 1-stop-shop. Tell em I sent ya ;)
Now that I talked your ear off. Here is the finished product ready for install.
