Best Gear oil for NEW tranny?

[RipperXX]

Ok so it's not NEW it's rebuilt. But there are zero miles on it. And I want to reduce the ware as much as possible and it shift as smooth as possible.

I have heard a lot of good and bad stuff about BG Syncromax so I am hesitant to use that. Does anyone have a more conventional solution that works well? ( I don't mean it has to be a conventional lube so long as it is a gear oil)


According to the papper that came with it. Mobile 1 syn, Redline MTL or original Mitsu gear oil is all they warrenty the tranny with. So I am thinking Redline or Mitsu gear oil.

Anyone have anything to say about the two?

 

[TSIfreek]

I have found RL MT 90 works very well and is all I use along with everything else redline in the drive train.

 

[GVR4592]

I've tried pretty much every fluid out there, the two best for ease of shifting, in my opinion, are BG Syncroshift, and Pennzoil Syncromesh. I think Redline gives better protection, and that's what I'm currently using. A mix of 2 quarts Redline MT 90 and 1 quart of BG/Pennzoil would probably work pretty well.

 

[wortdog]

I believe you said you have a Jack's transmission, right?

They recommend Mobil 1 because that's what they've set up all the bearing preloads for, and they also spun it up with Mobil 1 in it for testing purposes. Why would you run anything else?

 

[housegsx]

Mobil 1 synthetic ruined my original transmission. The minute I changed it, it started grinding into second.
I would stick with the pennzoil or redline. I run the pennzoil in my tre.

 

[GVR4592]

Mobil 1 isn't a GL4 fluid and it will destroy yellow metals, like the brass synchro's in our transmissions. GL4 fluids will typically have less than half of the extreme pressure additives of a GL5 fluid. Those additives are corrosive to the synchro's and will tear them up really quick.

 

[wortdog]

GL4 oils have the exact same corrosive additive (sulphur/phosphorus) as GL5 oils. Its just that standard GL4 oils have 10x less of it than standard GL5. Mobil 1 synthetic only has a little more sulphur and phosphorus than standard GL4 oils. Even Redline MTL has a bunch of phosphorus in it, which can also corrode brass/bronze in the presence of moisture. The quick and dirty way of telling how much additive is in a gear oil is to just take a whiff of it, the more rotten the smell, the more EP additive.

The other thing nobody ever mentions is that the sulphur in GL5 and GL4 gear oils doesn't corrode brass at all until the oil is over 230-250 F, which you'll only see if you're trying to set land speed records, road racing, or rallying.

 

[RipperXX]

Sounds like I will go with the Redline MTL, however I am suprised no one said anything about the OEM mitsu oil.

 

[SVP97GST]

The other thing nobody ever mentions is that the sulphur in GL5 and GL4 gear oils doesn't corrode brass at all until the oil is over 230-250 F, which you'll only see if you're trying to set land speed records, road racing, or rallying.

Land speed records...

 

[TSIfreek]

GL4 oils have the exact same corrosive additive (sulphur/phosphorus) as GL5 oils. Its just that standard GL4 oils have 10x less of it than standard GL5. Mobil 1 synthetic only has a little more sulphur and phosphorus than standard GL4 oils. Even Redline MTL has a bunch of phosphorus in it, which can also corrode brass/bronze in the presence of moisture. The quick and dirty way of telling how much additive is in a gear oil is to just take a whiff of it, the more rotten the smell, the more EP additive.

The other thing nobody ever mentions is that the sulphur in GL5 and GL4 gear oils doesn't corrode brass at all until the oil is over 230-250 F, which you'll only see if you're trying to set land speed records, road racing, or rallying.

Were did you come up with this informaton?

 

[Defiant]

http://www.stealth316.com/misc/pennzoil_gl-4gearlub.pdf

 

[JackM]

Use the stuff that was designed for your trans. The factory gear oil shifts better than anything else and has excellent shock resistance. I have people with over 700hp using the factory oil in my trannies and no issues.

Jack

 

[housegsx]

Use the stuff that was designed for your trans. The factory gear oil shifts better than anything else and has excellent shock resistance. I have people with over 700hp using the factory oil in my trannies and no issues.

Jack

Can you show me a picture of a bottle of the Mitsu stuff? A while ago before I even had my transmission rebuilt I went to my local dealer and asked for a couple quarts but they said it's always in bulk in a drum and they don't sell it...

 

[JackM]

Yes, we have to get it in the 5 gal drums too. If you want just a few quarts, and can put some in a container and ship it if that will work.

Jack

 

[Defiant]

Can you show me a picture of a bottle of the Mitsu stuff? A while ago before I even had my transmission rebuilt I went to my local dealer and asked for a couple quarts but they said it's always in bulk in a drum and they don't sell it...

Ah, the usual cooperative, helpful, go stuff yourself attitude of the Mitsubishi dealer.

A decent service manager would say, "Bring her around, we'll drain and fill it for you." Hell, they'd make it back on harmonic balancers that week anyway.

 

[lenny 15]

last month i asked Jon at TRE what the best oil would be to run in my TRE stage two tranny, this is what he replyed:

"We really like the 6 speed gear oil thats used in the EVO MR transmission. It's the whip.
Jon Ripple"

 

[outlawdsm]

That's funny! Jack has been recommending the factory oil for over 2 years now and everyone used to think he was nuts..... Now people are starting to see its potential and also recommending it

 

[RipperXX]

Damn I already got the Redline MTL, well maybe in a few thousand miles I will try to get some of the OEM oil and change it.

At least then I can compare the two right!?

 

[Dream On]

I used 2 quarts of MTL and 1 quart of BG when I last changed it. I don't really notice much difference vs. synchromesh in my stock 142k tranny.

 

[Spoolin4Ever]

I have done pretty extensive research myself.

BG synchromesh says right on the bottle "For Front wheel drive transmissions", that stuff is too thin for an AWD...and the same for all the fluids with synchro in their name. They will shift smoother when cold, but will not protect under the heavy loads an AWD tranny sees.

Redline MTL is also not the correct fluid for an AWD, it's MT90 that meets the specs.

You would be ok for a while with a new tranny...but for the long run, use the MT90, it's thicker so it protects better for an AWD.

OK, so here it is from the Redline website (notice the MTL is only 70w80, not 75W90, which is the factory spec, LOOK IT UP IN THE BOOK):

MTL

This 70W80 GL-4 Gear Oil (SAE 5W30/10W30 engine oil viscosity) is designed for use in manual transmissions and transaxles. Provides excellent protection of gears and synchronizers and its balanced slipperiness provides a perfect coefficient of friction, allowing easier shifting. Popular in many BMW transmissions and in most Honda and Acura transaxle applications.

MTL is the correct product for Big-Twin primary chaincase. Big-Twin transmissions should use Red Line Heavy Shockproof, while Sportster and Buell Tranmission should use Red Line 75W90 GL-5 gear oil.


Here's the blurb on MT90:

MT-90

Popular in Nissan, Toyota and Mazda manual transmissions and transaxles as well as other selected applications, this is a 75W90 GL-4 Gear Oil that’s slightly heavier than MTL. Provides excellent protection of gears and synchronizers and its balanced slipperiness provides a perfect coefficient of friction, allowing easier shifting.


Notice it says excellent protection of gears and SYNCHRONIZERS...? Let's face it, our synchros go out pretty easy....

Anyway, the factory spec'd weight is 75W90, and GL4: that is MT90....

My last transmission failed about 30K after running BG Synromesh in it, from advice people on this board and local dsm club told me: BAD ADVICE, that is thin as water....

The tranny had 99K on it when I bought it and would crunch into second when cold...everyone said use the BG Synchromesh, so I did...Then 30K later, first gear got weak (or is it the main bearing), not sure...what would happen is when I would rev it in first gear up to about 5K, the extra revving didn't equate to more power, it's like it was spinning but not accelerating...all the other gears still worked like normal..well besides the 2nd gear crunchy thing but you know, they still functioned...so I know it wasn't the clutch slipping or anything else but the tranny.

 

[eclipsh]

Odd... I've had BG Synchromesh II in my rebuilt tranny for 20k miles and it still shifts beautifully. I briefly had Mobil 1 in there, drove it one trip into town and drained it right out. It shifted like crap with it. I poured the BGS2 in and it was shifting like a champ again. This is with TRE synchros and properly preloaded bearings.

 

[Defiant]

It would seem our mileages are subject to variation. The Synchromesh I put in when I got the car, 60K and however many years ago, is still working splendidly.
Then again, I shift my transmission, it doesn't just "shift". And, as though you've not heard it before, I double-clutch, synchronizers or not.

 

[RipperXX]

Defiant, I am curious of your openion here about the MTL. Although I am parinoide and will most likely replace the new MTL with MT 90 at my first oil chage.

 

[Defiant]

I'd buy anything Redline makes, after asking them. Give them a call, they're friendly people and won't hand you any crap. I think the same applies to all the small-market makers, although I'm not keen on Lucas.
I'm just not very neurotic about lubricants. The worst stuff you can find today is so many generations better than what was available when these cars were built that it's amazing. You do need to be aware that the additive packages in some gear lubes is not compatible with the metals in our synchronizers, and that the 420A gearboxes are another kettle of fish entirely. I settled on Pennzoil because it's cheap and it's been working for me. I've not had cause to go comparing.

 

[Splitpi]

I'm running Amsoil.