New super diff review


Well-Known Member
new york
First off you need a IRC CNC Diff cup set and ONLY USE THIS KIT ONLY!!! and a new set of HPI diff gears and do not use clone gears or results will not happen. Build the diff dry and use the sealed bearing in shaft bores and see if you can add one shim one each end that comes with kit , If not leave out for now. Next fill 1/2 the diff with peek metal polish paste and bolt halves together without gear on and chuck up on one drive cup and keep the main body from spinning and run in one direction for 20mins at very low RPM, Stop. clean out the now black compound and clean. refill with fresh and bolt back up and now run the other way for 20mins at low RPM,Stop. clean out again but this time add shims to both halves to almost lockup ruff turning when dry fit and refill with fresh compound and bolt back up and run in at 10mins this time at ultra low RPM , clean out, add fresh and run it at 10mins going other way, stop. now on this tear down keep track what gears and plates came from where and clean perfect. knock out bearings and o-rings and toss in trash . again clean, clean, clean. Now use the bushings and new o-rings when building this time and not bearings use the shims that you used during burnish run in and build diff dry . It will feel wicked tite but smooth . Now here is the kicker as now fill the diff 3/4 full of John Deere hy-guard hydro oil !!. with the gear pack now burnished in to ultra close fit you can now use thin hydro fluid and it will gear pump like it has thick diff snot. The nice thing about hy-guard oil is it has a wetting agent in it to shed heat to housing and a anti-foam to keep the action the same from the start to finish of run. Again only use the IRC kit and true new HPI gears and you will be amazed at the results and how well a diff SHOULD work with the right fit and thin oil.........