Alberto v05

So is it true that you need to put Dexron iii in your t56 borg warner 6 speed transmission even though that's oil for a automatic transmission??

JaYZeig

iTrader: (11)

yes sir..i run this in my m6 trans..

you also might find a tag on the trans itself saying that this is the correct fluid to use.

Alberto v05

I just find it weird putting auto tranny fluid in a 6 speed?? But why auto what does auto tranny oil do once it's in the m6?

JaYZeig

iTrader: (11)

its just how gm built the transmission, to use this fluid.

really dont have an answer for ya there.

Alberto v05

Okay i see, I'm going to do some research on that to learn more about why auto oil and instead of synthetic gear lubricant LS 75w-90.

If your wondering why i posted this thread my mechanic told me that the m6 runs on automatic oil and i was shaking my head??

Floorman279

iTrader: (11)

Seriously, don't run anything other than dex 3 in ur trans.........not even gm synchromesh.......although some do without issues......

bww3588

iTrader: (49)

Nothing wrong with synchromesh. Many people on this board have used it with great results.


The reason for atf in most manuals today is the design of the synchros. The friction material is the same used in the clutch packs of an automatic which require atf to work correctly. Gear oil will just not cut it in a modern synchronized transmission.

Alberto v05

So is this the reason why my gears don't go in at high rpms when I'm running the car at full potential i try to shift at 6 grand and the gear won't go in??? I thought it was my synchros or the master cylinder or slave master?

MikeFSKSpeed

iTrader: (37)

Ford T5s use standard Type F ATF too

Alberto v05

So as long as i change the fluid it should be good or did i miss up my m6 cause i put mobile 1 synthetic gear lubricant LS 75w-90?

Exidous

iTrader: (11)

While it is possible it messed with your syncro's, you will not know until you put some ATF back in. You can use DEXRON VI as well as DEXRON III. If you are still having issues afterward you may be looking at a rebuild.

ls1 1990 VN

Standard ATF etc can be a bit notchy with shifts, use a good synthetic like Redline high temp ATF, gear changes will be way smoother.

redbird555

iTrader: (14)

well you should never put synthetic anything in a stock t56 if you look on the side of the transmission you will even see a sticker that says dexron III only. anyway you may have messed up the synchros with the gear lube as it will not let the synchros catch and may cause hard shifts also.... remove it immediately and fill it up with synchromesh or some type of good dex III atf fluid.

ls1 1990 VN

What planet are you from? There's nothing wrong what so ever with putting synthetic in a stock T56.
Oooooh the sticker must be 'obeyd' Doesn't the oil filler say Mobil 1...Ohhhh no! all those poor stock engines that have anything synthetic in them.

SSCamaro99_3

iTrader: (1)

It has been a while since I read up on it, but the early LS1 T-56's (I know there is really no difference 1994 up) had conmpressed paper, want to say blocker ring, that swelled in the presence of synthetic fluid.

redbird555

iTrader: (14)

Ding ding ding!!

Umm please do research before you post... I didn't say it wouldn't work I just said it shouldn't be done because as was stated t56s before late 2001 used paper synchros and synthetic fluid does not allow the synchros to function properly... And yes the sticker on the side of the tranny should be obeyed.. Dex III is the fluid it takes not VI, II, or type f i dont recall saying anything about a brand though... And the filler cap does not say Mobil 1 only corvettes had that cap

JaYZeig

iTrader: (11)

jmd

iTrader: (4)

Read this carefully: https://ls1tech.com/forums/manual-tr...ift-3-2-a.html
It's a very real possibility the synthetic isn't a proper break-in fluid for a carbon blocker ring trans. And frankly, if the car isn't being pushed hard upstairs with a lot of power, the synthetic isn't going to be as effective at protecting the headset gears as a sprayer setup.Mobil 1 began in the 90s Vettes to save the cost of an engine oil cooler. The accountants chose that one.

Don't automatically assume everything synthetic is better for every situation.

bww3588

iTrader: (49)

As stated, the synchros do not like synthetic in certain years.

That being said, you can run dex 3 or dex4. All newer transmission fluids have to be able to replace all subsequent fluids. If it calls for dex 4, you can't run dex 3. Works like Microsoft programs.

RevGTO

iTrader: (12)

I replaced the factory fill at 85k with Mobil 1 ATF in my 01 T/A. The 1-2 shift became notchier and even ground sometimes on cold mornings. Drained it and replaced it with Dex III, problem solved. Dex III only for me.