H type helical LSD(Mfactory)

[MK1gGT-Rob]

ok, so mtf is specifically an aftermarket fluid designed to replace atf in mtx's?

Synchromax is recommended for manual transmissions that specify an automatic transmission fluid. It’s also ideal for 4×4 transfer cases and motorcycle gear boxes. Synchromax is fully compatible with all types of friction materials. It provides excellent corrosion and oxidation protection without affecting the soft metals commonly found in manual transmission synchronizers.

[MFactory]

No.

MTF = Manual Transmission Fluid
ATF = Automatic Transmission Fluid

MTX = Manual Transaxle (i.e transmission)

All manufacturers have their own Manual Transmission Fluid. ATF is thin because it was designed to be pumped around the transmission by an oil pump. Manual transmissions do not use an oil pump.

When a manufacturer specifies to use ATF, this is the equivalent of them specifying to use regular 10w30 engine oil (i.e Honda). For a normal run of the mill grocery getter, sure, for a while. For something that will be driven other than by an OAP, no, not suitable.

[MK1gGT-Rob]

ok well even ryan will tell you that our boxes call for atf from the factory. I'm going in my basement to look for an MX6 manual. not trying to start an argument with you...


Synchromax is recommended for manual transmissions that specify an automatic transmission fluid.

[MFactory]

Is your car 100% stock, and only used to go to Walmart?

If not, use MTF. Not trying to start an argument, just giving you advice

[MK1gGT-Rob]

Well I'm listening. I just thought you were denying that some mtxs came with ATF (which I just found in my manual, API service GL-4, GL-5 (SAE90, or 80w-90), or ATF Dexron II)( my manual is 89 tho later ones dont list the gear oil). I had some blowouts with speed shop owners not understanding why a garrett t3 turbo needs a restrictor amongst other things, so I dont know what to expect, lol.

Royal Purple Synchromax sound good then or Torco if I can find it? AmsOil had a disclaimer against limited slip.

[MFactory]

Yes, some manufacturers suggest using ATF (or regular engine oil). I know all about this, as I specialize in Honda's and get into this sort of discussion with customers and tuners everyday.

What they also assume though is that your grocery getter does what it was designed to i.e go get groceries.

MTF is of similar viscosity as ATF, but tends to include a cocktail of beneficial additives for a manual transmission. This is why I recommend you to use MTF in your non-grocery-getter.

The easiest (and cheapest) MTF to get is Pennzoil Synchromesh (Royal Purple Synchromax is 50% Pennzoil, 50% engine oil). Then you have GM Synchromesh (re-branded Pennzoil) and our recommended fluid (but more expensive) Torco MTF.

The Amsoil statement was probably aimed at real LSD's (i.e Plate Type). A Helical LSD isn't really an LSD, as it doesn't function when one wheel is off the ground, whereas a real LSD would. A Helical LSD is actually a TSD i.e Torque Sensing Differential aka Torsen

[MK1gGT-Rob]

thanx. i have to repair a 1/4" crack by my reverse light switch (Hercules wasnt a good mechanic) and then i can refill it. i'm letting it drip dry for a day or two, then I will clean it up and epoxy the crack, refill it to be ready to drive Saturday morning. I'm going to get an exhaust and an alignment. (recommendations on methods to fix the crack welcome, except replacing the case half, i'll do that in the future, just need it to hold for now).

[MK1gGT-Rob]

What is your opinion of Lucas Oil treatment as an additive for mtx?

[Inspector 24]

Jeremy (ragnarock01) and I have been running Redline MT-90, and/or 75w-90 GL-4 gear oil in our H-Boxes for a long time now. Were I to venture a guess, approaching 80k miles between three cars. No issues, always great shifting.

[chief tool]

the H-type box does need a thin oil to get thru to the 5th gear section.

all the german probes with the h-type box run ATF as they all use transmission oil coolers.

I use ATF in my box and alot of other guys do too...its not normally something you would do in an MTX...Mazda only specifiy its use for -10 or less...

However, I have found that useing ATF clears up alot of the shifting issues.

Once I get the new LSD I was planning on switching to a synthetic gearbox oil like royal purple.

I have used 75/90 before and ATF seems to work better.

[jesiotrot]

I've run ATF in my h box with a guru torsen diff before, also run full synthetic 75w90, didnt make **** of a difference when it comes to noise. IMO H boxes synchros dont like ATF.

If I grab my drive shaft and shake it back and forth all sorts of clunking noises eminate from inside the box, just like a stock diff would, are you sure these noises arent being amplified by those AWR mounts?

[monoxidechild]

i do a mix for my trans. a guart of gear oil, and then top it off with high quality atf. thats what ive been doing for years. and ive never had a single trans failure through over 6 running probes in over the last decade. and i do push them alot more then just going to walmart.

the 1 quart of gear oil i know isnt alot. but it gives me that little piece of mind. straight atf still makes me nervous.

[MK1gGT-Rob]

used to be you ran synthetic ATF with a quart of Lucas Oil treatment, right Pat?

[Inspector 24]

God, I love how much fluids in cars are debated!

[ragnarock01]

The Mazda MX-6 manual does say for turbo cars, to use "SAE 75W-90, ATF: DEXRON-II".

However! That is for "All-season." For temperatures above 0 degrees F, it recommends "API: GL-4 or GL-5, SAE 80W-90 or SAE 90". You can view the manual by downloading this PDF.

As Ryan said, me and him have been using Redline MT-90, and/or 75w-90 GL-4 which are perfectly in line with what the manual recommends, except for the part where they're specifically manual trans fluids. The only problems I've had is my trans has gotten stuck in 1st a few times, but that has more to do with it being an old, abused trans . Rob, what weight is the ATF oil you were using? If you were going by the manual I would assume it was 75w-90?