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Rear Differential Fluid on pre 07 sti

23K views 14 replies 12 participants last post by  rr1911  
#1 ·
30k coming up and i already did my tranny fluid. I went with valvoline 80-90 non synthetic. Ive done alot of research on both tranny fluid and diff fluid changes. I didnt know that in 07 the stis had a different lsd installed so thats why this thread is for all pre 07 stis. I have an 04 witch i belive is the same as all the rest.

Im most likely goin with Motul 90PA as it was reccomend to me and have read godo things about it. So the year is 2009 and we all have had our stis for a while so lets hear what everyone is running in their differentials. Some of us may have tried many different fluids and can chime in with information.
 
#3 ·
for the rear diff on your 04' use the OEM LSD fluid !
 
#5 ·
I dont want to buy , well ill say i cant afford to buy a 5 gallon barrell of subaru xtra s differential fluid. I would if they sold quarts. Like i said i did research and alot of people talk good about motul 90pa. witch is whati will most likely go with. I read good and bad about royal purple so i will skip that coice. Good things about OEM subaru x stuff, but im not buying 5 gallons.
 
#6 ·
^^^The subaru lsd oil (for rear diff on 04-06 sti's) is available buy the litre and available at almost any dealership.

The subaru extra s fluid is for the transmission/front differential (it's only ok to use it in the rear diff on 07+ sti's because they changed to a torsen differential).
 
#7 ·
The Motul 90PA has been great for me with all the track work, general abuse and some occasional drifting I do with it.

This morning we finished suspension work on a friends STi and when he bought the car the rear diff would chatter and grin A LOT. Since I have messed around with the fluid on these cars a bit he took my suggestion and put 90PA and instantly it became 90% better, over the months its become 99% normal, no chatter almost.

I HAVE heard of guys not liking it and get some chatter, once in a while when its been a local car ive checked the level and it was a little high and fixing the level made it perfect. There is only about a quart worth of room in the rear diff.

I would personally recommend trying the 90PA but the Subaru LSD oil they sell in a tin can is pretty good as well.
 
#8 ·
yeah im a big believer in the subaru LSD oil. i use it in my rear diff and mobile 1 full synthetic 75w90 in the tranny, which was like night and day in my tranny, it fixed some chattering sounds i was having.