Not to mention Mobil1 calls it a gear oil since it contains limited slip additives. When I called them they said they don't make a manual trans fluid. Of course SpeedSource uses Mobil1 in their trans but I don't know what. In other countries you can buy Mobil1 manual trans fluid - Mobilube SHC 75W-90
http://www.ibg.ge/lubricant.asp?lubID=14

 

75w30 ? ....................................

I got 3 bottles of MT-90 the other day. cuz I dont really like the idea of mixing it with MTL. I searched and found a lot of post saying that people with *pure MT-90* have some really poor shifting quality issue, Im just wondering how *poor* it can be? is it like grinding(I hate it) or just not very smooth ????

 

As you can see from my sig pic, I race this car. I don't granny shift.

 

then maybe u should get 75w140ns

 

I'm lazy to correct my typo.

 

J, this got me thinking so I looked in the FSM for specified lubes and such. Have I missed or otherwise forgotten the latest info about what is working for us? In the FSM, Mazda lists GL-4 or GL-5 in 75W-90 as an all-season lube for the tranny and GL-5 in SAE 90 for the diff. That's why I use the Mobil1 when I am not experimenting with other lubes.

 

No TSB/MSB that I am aware of - it seems Mazda just quietly changed the recommendation in the owners manuals - probably to not have to pay warranty claims on trans that fail (syncros) due to the use of a GL-5 lubricant.

 

Okay. Thank you, Sir. Was that back when Mazda was intructing the dealer techs to mix the fluids?

 

Not sure what you are referring too on that one.

Best I can remember, the changeover in the recomendation came in 2006 to a GL-4 oil for the trans.

 

Sir, as in a moniker denoting respect. Oh, you mean my other comment....

A couple years ago Mazda told their dealer techs to blend a bit of ATF in with the M/T fluid. I don't recall what the ratios were nor why they were doing it. Probably synchro grinding.

 

I hate reading this site. Always making me 2nd guess anything I've done.

I put this Amsoil gear oil in both my tranny and diff.

http://www.amsoil.com/storefront/svg.aspx

When the weather was really cold (-20C / 0F) I'd get some minor grind if I tried to shift fast until the car really warmed up. Now that the weather is warmer (approx 0C/32F), it seems fine no matter how fast I shift.
Does that oil look ok? And has anyone else seen cold weather shift issues regardless of oil used?

The car is an 04, Oil went in at 46k km [29k mi], just a few months after I bought it.

 

I would bet a paycheck(if I still got them) that your shifting troubles are from that particular lube to be of the "clinging types" that I warn people about. Severe Duty oils, and others like them, often have the tendency to try and absorb the driveline shock by clinging to the synchros and gears as they turn. The problem with this, and this is strictly my own opinion, comes by way of the clinging nature also causing the synchros to fail to spin up or down quickly enough to meet the speed of the shaft they are attempting to mesh with.

 

So the theory is that certain oils will over lubricate the synchros? Reducing the friction to the point where they can't spin the shafts quickly enough for fast shifting? If I have no problems with it in the warmer months, and can live with shifting slowly during cold weather warm ups, I'm guessing I should be fine leaving this oil in?

 

Not exactly.

 

The theory on why there is grinding, or the theory that I'd be ok to leave the oil in

 

AMSOIL Severe Gear is a GL-5 lubricant that is great for your rear diff - and will absolutely, over time kill the syncros in your trans.

For your trans, you want AMSOIL MTG (Assuming you want to use AMSOIL products)

http://www.amsoil.com/StoreFront/mtg.aspx

or for better shifting, you can mix 50/50 with AMSOIL MTL

http://www.amsoil.com/StoreFront/mtf.aspx

As for your other question on trans fluids, Charles is right in that GL-5 fluids do not have the right "grabbiness" (a technical term) for syncros to work efficiently - they do tend to be too slick as they have many Friction Modifiers (FMs) in addition to the EP additives.

But the real issue with GL-5 fluids in a trans with syncros is that syncros use softer metals and GL-5 fluids have way too much Extreme Pressure (EP) additives that actually wear out these softer metals over time, reducing the ability of your syncros to function properly until they just eventually fail.

GL-4 fluids, like the ones I linked above, have some EP adds, but tend to be formulated for the "right" friction for the syncros to work properly and also have much less EP additives (usually different ones as well) to keep from prematurely wearing out the syncro soft metals.

Also, there are many GL4/GL5 combo fluids, like RPs Max Gear, BG Ultraguard, etc, etc, that claim to work in manual trans and diffs. Some use and seem to have successwith these fluids in manual transmissions, but I would shy away from these combo fluids in a manual trans as they will still have too many EP and FM additives (which are required to meet the GL5 spec) for good syncro operation and wear - not all agree with this, but I would rather be safe than sorry as trans rebuilds are not cheap as most of our trans failures seem to be from the syncros failing (or being so slow in operation that we grind the trans gear teeth or break them off completely).

 

Have you ever seen, not heard, but seen anyone blowing their engine because of the oil they picked?
I'm sure $1.49 warren oil from Winn Dixie would do just as well, It's all a bunch of crap just change it regularly and relax. $6 a quart won't make any difference you maniacs.

 

thanks for clearing that up for us..

how did we miss this....

beers

 

Have fun

 

We're talking about transmission and differential fluids right now, idiot.

 

Forgive him, Ray.

There are people on earth who still cannot read.

I told him to have fun already.

Just forgive him

 

LoL Finally someone got ray mad

 

The only person who truly annoyed me on this forum was Tajabaho with his incessant tweaking of his nitrous system. On the other hand, he did prove for me that I am so good at it that even he couldn't screw it up. When I use the terms "*******" and "idiot" they are usually in a big-brotherly, Denis Leary, sorta way.

 

Good old Leary..... I met him in real life once!

 

Hey dude, when you're ready to upgrade your exhaust, you can save tons of money using this device instead of one of those thousand dollar setups.


http://cgi.ebay.com/ebaymotors/Exhau...spagenameZWDVW

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