Front differential fluid help
 

Need some help and thought I'd see if a few of the well knowledged Subie owner here could help.

What is the recommended front differential fluid for an 03 Subaru WRX?

Four days ago, I got my tranny serviced at Jiffy Lube. Several things have me very concerned since then.

First was the lady working in the front that opened the door and yelled into the shop "Just do it" in a very scary demanding voice. Followed by...

Four mechanics standing over my car staring at the turbo with a perplexed look on thier faces. (At this point I went out into the shop asking whats wrong). Standing over them the remainder of the time till they completed the filling of the tranny. Whick leads to my third concern.

I've only driven the car a couple of times for maybe ten miles total since. Both times I've had a little smoke come from the hood while stopped and the dreaded burning oil smell. I've traced this to fluid being spilt on the turbo. What really concerns me is its harder to engage reverse and first while stopped. While driving I now have to practically use force to get it into first while moving. Much harder to shift into first while rolling now. Even shifting between 2-5th does'nt seam as smooth as before the defferential service. Feels "clunky" I guess you could say.

I bought the car used and don't have an owners manual. Can anyone help me with what fluid is recommended for the tranny, so I can go back up to Jiffy Lube and find out what they put in.

I've checked the tranny and oil levels three out of the last four days since the maint. and they seem fine. Also not a single drop of fresh fluid in the garage. The rougher shifting is what really concerns me.

Certainly open for suggestions.

There's no such thing as "front differential fluid". The front and center diffs share gear oil with the rest of the transmission.

Many of us use Redline Lightweight Shockproof. Unfortunately it's not rated GL-... um whatever the manual recommends, but it works great. Just don't put it in the rear-end.

The choice of transmission oil will have a huge effect on the way it shifts. Like Scott said, use Redline Lightweight Shockproof. I used it in my old WRX and now my STi, and it made a big difference in both cases.

Since I used to get a good discount at a dealership, I run OEM tranny fluid. I like the way the tranny shifts, although I do have to try a couple times to get into Reverse...no biggie. But it seems normal gear oil is too slippery for the WRX transmission. You could add some synchromesh to give the synchros more grip, so I've heard.

Hummm,

Very interesting. Maybe the previous owner changed the tranny fluid to something a little smoother. All I know is the tranny is much rougher shifting now since the fluid change.

I'll do a little research. Thanks

Gear oil has to be slick enough for the bearings and grippy enough for the synchros to...grip.

Why not?

It's not very slick since it has to allow the synchros to grip. Mobil-1 is good for the rear.

The rear end needs a friction modifier (or lack of friction modifier, I can't remember) or it won't work properly.

Ask Deede, S-Squared put Shockproof in her rear diff and it drove like shit. :(

Errr hopeful Deede will chime in and defend her rear end.

That lil blast of smoke is more than likely the small amount of oil that dripped down block when they changed the oil and filter and is burning off. I was the asst Regional Manager for q-Lube now jiffy lube for 6 yrs. It was very common to have some "Frame Drips" even after we wiped the excess off. I haven't checked the manual for exact viscosity and GL ratings for my subie yet, but redline is a good product, and in the 6 yrs I was slingin lube around, Subaru always had something different than the norm.

The rear diff fluid only really matters if you own an STi. The WRX and older RS had sealed viscous units, you could throw anything in there that can legally be called "gear oil" with no ill effects provided it's GL-5. Same with open diffs. Because of that I don't think I ever bothered with rear diff oil on the RS. My Miata has standard Redline 75w90NS (no friction modifier) for the Torsen. Or maybe it's 75w90... whichever one is slipperier... I can never keep Redline's gear oils straight.

say that 5 times really fast!

hahaha. Nice.

I don't know what the effects are in the WRX, but the STi for sure is bad to put the wrong gear oil in the diffs. The correct stuff for the rear diff. has to be specially ordered from the dealership IIRC. I'd recommend getting the Shockproof stuff for the other diffs. like the guys recommend. It is awesome! The car shifts alot smoother.

If you put the wrong stuff in the car it makes all kinds of weird noises and drives really awful.

Hopefully nothing is wrong with your vehicle. I wouldn't drive it too much until you fix the problem. Good luck.

I have Thursday off work. I'll return to the shop then and find out what exactly they put in and go from there.

My biggest concern is the wrong fluid is in the tranny. YIKES! It could be the previous owner was running a better tranny fluid and I got use to the smoother shifting. The shop might have put the correct fluid in, it just does'nt shift near as smooth.

I've awoken in the middle of the night in a cold sweat dreaming about that woman swinging open the door and screaming " just do it!" Oh that voice.