After 2-3 days of constantly checking my work and making final adjustments, I was able to inch out for a test drive. Butt was clenched the entire time…
There were a number of things to monitor – too many… from brakes all the way through to engine, driveline, suspension and diff… As they checked off, I focused on the new diff setup.
Having had experience with an open diff, Cusco 1/1.5 way and a TRD 2 way, I was eager to monitor the new set up. Set at a 100% lock, the entire test drive involved getting the clutch packs to engage gently with new mineral oil. This was challenging especially with the packs being so new – they engaged even at the slightest turn-ins or clutch pedal movements.
That aside, I’m very impressed with setup so far and how well the oil is responding. The recommended oil to use is Cusco’s own 80w-140, but because it’s been out of reach lately, I had to improvise with what’s available (my orders haven’t been arriving since October).
The oil we’re after here is an API GL-5 spec mineral oil that can handle extreme pressures and contain additives suitable for L.S.D setups (look for EP – extreme pressure label on the bottle). The viscosity 80w-140 or 80w-90.
Two oils available off-the-shelf these days and meet the criteria are:
- Motul 90PA (premium mineral) (not always available).
Motul Motylgear 80w-140 (premium mineral)(discontinued)- Penrite 85w-140 (also premium mineral).
After going back-and-forth, I decided to use Penrite’s gear oil – and have been quite pleased with how it is performing so far. How it interacts between the clutch packs is predictable and the clunking noises are smoother in comparison to my earlier setups – eager to see how this works out longer term. I’ll be using this oil at least until I manage to perform a full break-in (figure 8s).
For synthetics (if I ever end up trying them), I managed to find one that is available locally:
- Castrol Syntrax LSD oil 80w 140 (fully synthetic GL-5 spec).
Note: Do not confuse GL-5 spec with your transmission for AE86s – there are components in the transmission that’s made out of brass (i.e. the synchros) – the sulphurs/ additives in GL-5 spec oils will damage them. If you’re using a stock OEM T-50, the recommended oil spec to use is GL-4.
IAD 