I have a 99 OBW. Does the lube in the front and rear dif need to be changed periodically?? This was brought to my attention, when watching Goss Garage, on Motor Week, on the PBS channel. Goss said the lube needs to be changed on AWD vehicles as often as every 30K miles. I don't have an owner's manual to look for an answer to this question. Anyone know, and if so, with what recommended product.

 

Thanx,

 

Larry (Rooster2)

Yes, 80/90 W gear lube.  

I've been using the Walmart syn. blend (cause it pours much faster) for years with no issues.

Personaly, I would change it when it starts to change color, since Subaru's have a dipstick this is easy to keep up on. I think 30k is a little excessive though. Good old gl5 80w/90 any brand should be fine. Also if it has a lsd don't forget to add a friction modifier, I like sta lube equatourque

 

As for synthetic gear oil, I don't know about subaru, but have seen many a failed rear end caused by synthetic gear oil. I know Dana rear ends cannot use synthetic gear oil. I was told this would void the warranty when replacing the rear end in a dodge for a customer.

API GL-5 rated gear oil 90w90 or 75w90 conventional or synthetic is fine. 

is it a 5 speed? many people report problems with synthetic oil in the manual trans so, stay with 'dino' oil.

 

on the auto - the diff is completely separate and synthetic is OK. (Redline Lightweight Shockproof in our 03 H6 OBW helped cut diff noise/whine by about half)