Differential & Transfer Case Oils

Vehicles will go most of their life without ever getting a diff or transfer case oil change, we had our Adventra for years and since we do work the diff fairly hard in our off road Adventra’s I thought it would be a good idea to see how easy it is to change the oil.

(left) Penrite Pro Gear Oil 75W-85 1ltr (right) Penrite Gear Oil 85W-140 2.5ltr

To my surprise good quality oils are not really that expensive, I purchased both of the above oils for just under A$50 at Super Cheap Auto and this is all you’ll need to do a full oil change on the front & rear diff and center transfer case – believe it or not the 1ltr bottle will give you 3 changes apparently to give you an idea how little amount of oil is actually inside that box. It also might be a good idea to find a hand pump to get the new oil in we picked up something from Autobarn for $20 which you can reuse.

Rear diff drain & fill holes

All you need is a few sockets, undo the drain plug, drain out the old oil and close it up after; open the fill plug and fill the diff up until there is fluid is just starting to leak out the fill hole. I was told it would drain similar to what I put back in but that wasn’t the case for me so I suspect some has gone missing in its life.

Draining rear diff oil

After it’s all empty we used a hand pump to be able to fill it back up, you can see how the oil colors are way different giving you some idea how past due this might have been.

Keep pumping that oil in until its leaking out the fill hole!

Once you’ve finished there you can do the front diff, since that uses the same oil the process is very similar, drain from the drain hole and fill from the fill hole. The front diff for some reason though has a hex screw to be undone.

Front diff fill and drain hole locations.

After you’ve done front and rear diffs you can do the center transfer case, this is fairly easy compared to the first part there is just not a lot of room to get to the fill hole.

Transfer case fill and drain hole.

Overall once you’ve done it once, its very easy to do again and if you haven’t done it on your Adventra yet I would highly recommend, it’s on the list of things to do on a nice day!