5eat fluids change can you use extra s

I need to change my fluids in my auto trans. Should I use the redline stuff? But how does this "godly" extra s work for us auto guys. Can I use it in my rear diff?

Also it there tutorial for the front auto trans change? I've read that the front diff oil is in a seperate area than the auto trans fluid. Can anyone confirm this?

Stick with OEM. If you put out of spec ATF in the JATCO 5EAT unit, chances are it might slip and cause damage in the long run. The consensus is that the OEM stuff is great and if you really really want a synthetic aftermarket ATF, then go with Amsoil.

For the automatic, the ATF is NOT shared with the front differential, the two units are separate and each uses it's own fluid. Running extra-s in the auto is asking for trouble. I'd say the automatic is one thing where you definitely don't want to experiment with fluids.

You're looking at any good quality 75w90 fluid for both front and rear diffs.

You're looking at any good quality 75w90 fluid for both front and rear diffs.

What he said.

I think you are. People are using Extra-S because their shifting behavior has changed for the better. Since that's a non-issue for us, just go for, example, Valvoline synthetic 75w90.

Also, the manual guys have to use 75w90NS (non-slip) for the front afaik, whereas we use plain 75w90

There is no center diff on the 5EAT, only on the manual drivetrain. Even in that situation, the center diff is a sealed unit and needs no service afaik.

Two diffs only: front, rear.

So subaru atf for the trans and 75w90 redline for the diffs?

Yes, that is a great combo.

Order the case of ATF from Jeremy at Fredbeans...great service and good price. He might have the redline too.

this is a good thread.

I asked this same question not too long ago.

^not true. the automatic has a center diff. all subarus auto or manual have a center diff. the 5eat has a VTD center diff wich is lubricated by ATF fluid along witht he reat of the auto except for the front diff wtih is seperated and uses gear oil. the 5eat should take subaru ATF mercon fluid. you can put estra-s in the front diff only. gear oil is too heavy for automatic trans' and if you put it in ther, it will not work and you will ruin the trans.

Here is where I got my information from and this is what I know

http://www.subaruspecialists.com/mainframe/frameAllWheel.html

In vehicles with the 5-speed manual transmission, the All-Wheel Drive uses a viscous coupling in a center differential inside the transaxle case

Automatics get this

Subaru vehicles equipped with the 4-speed Electronic Automatic Transmission (4EAT) feature a different type of All-Wheel Drive than with the 5-speed manual transmission. Instead of a viscous coupling center differential, an automatic transmission-equipped Subaru features an electronically managed continuously variable multi-plate transfer clutch located in the transaxle's tailshaft. Power transfer is governed by slippage in the clutch plates, which use a special friction material that easily handles the loads generated during power transfer.

4EAT or 5EAT, same functionality. No center diff, at least not in the same sense. So I think we're talking about the same thing. It's a center diff, but completely different and not called a center diff?

The two drivetrains are radically different, there are more things going on with the 5EAT

The Transmission Control Module (TCM) controls the All-Wheel Drive multi-plate clutch.

The 5EAT also is directly tied into the awd drivetrain via speed sensors, one in the front, one in the back and a third not sure what connected to, but it's in the transmission itself. These speed sensors determine operating and shifting behaviors of the 5EAT. When these sensors fail, the 5EAT falls back on the ABS sensors.

So the difference is not just that one gets a stick and the other a slushbox. If you were to swap the transmission, you'd have to swap most of the drivetrain as well.

More in the link above.

I know that many will disagree with me on this, but I am of the school of thought the drivetrain on the automatic transmission is of a better design under slip conditions. Simply put, the manual is more rigid and it has to be due to the fact that it can't communicate and work as closely because in between the wheels and the engine lies an "unreliable" variable in the form of the driver controlling the stick.

 

The 5EAT also is directly tied into the awd drivetrain via speed sensors, one in the front, one in the back and a third not sure what connected to, but it's in the transmission itself. These speed sensors determine operating and shifting behaviors of the 5EAT. When these sensors fail, the 5EAT falls back on the ABS sensors.

I can attest to this.

you want to prove it to yourself? press the up or down thumb buttons or paddle shifters while in D while slowing down. The car will stay in manual while your foot is on the brake or you're coasting, but the second you come to a compelte stop or you put your foot on the gas it goes back into auto mode.

I noticed this a few months ago and I thought it was kinda cool peronally.. the fact that subaru bothered to take this into account shows that they wer really thinking more than just throwing "features" at a product not designed for said features.

now if only the stock 5eat were beefier we'd be all set.