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Tranny Fluid - Your opinion

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Getting ready to fill up the 5-speed 71B

 

What's the best oil to use ?

 

Some say ONLY: GL-4 Yellow Metal Safe

Some say it doesn't really matter.

Some say go synthetic.

 

There are a ton of new oils out there now, viscosity varies a lot.

Hoping someone has experimented and can save me guessing.

 

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It does matter. GL-4 only, synthetic is ok to run as long as it’s GL-4. I run Lucas oil synthetic, others use redline or royal purple...all three are quality gear oils. My zx 5 speed shifts better on synthetic.

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Non yellow-safe fluid will eat the brass inside your transmission.

 

 

Yes, it matters.

 

Being in Ohio, it's not like you can easily find another transmission after you throw a few quarts of that magic voodoo Redline in there.

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If going with a synthetic replace the $5 rear seal, only takes a few minutes, and you should do this anyway. I'm using the GM Delco Friction Modified Synchromesh Transmission Oil. You can find it at Lordco a little cheaper than the dealer. It's about 3 times more than regular 80w90 GL4. You need 2 liters for the 71B.

 

I have it in my ZX 5 speed and it allows better shifting when cold, smoother faster shifts and I can now down shift without any grinding. I'm simply amazed with this stuff. Had it for about 5 years now. Best $36 CDN I've spent.

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GL-5 is for differentials. I'll look at the vid when I get home. There's lots of mis information out there. 

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Thanks MIke, 

Good to know, I see the synchromesh fluids and was leery of them because they appeared to be thin like ATF fluid, something I thought would not work well in a gear box.

I changed the front seal but I'm going to pull it because it's a single lipped seal. After putting it in I had wished I hadn't. 

 

Do you think I should pull the front cover and replace the front seal too ?

 

Did you flush your tranny before changing over to the synthetic ?

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If have a manual go by that.

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Here's what the American Petroleum Institute says, what the heck do they know..

API (American Petroleum Institute Classification) GL-4 (Gear Lubricant-4) contains about half the additives of GL-5. Higher concentration of Extreme Pressure additives in GL-5 gear oils may cause the softer metals, such as copper, brass and bronze – which make up the shift synchronizers of a manual transmissions - to suffer premature wear / failure. So, stick with the specified GL-4 classification, in any of your favorite synthetic brands.

 

Mike your fluid, GM Delco Friction Modified Synchromesh Transmission Oil

Synchromesh Transmission Fluid, Friction Modified is a synthetic blend manual transmission fluid designed specifically for use in GM manual transmissions. This fluid has excellent lubrication properties that prevent breakdown over time and reduce friction to minimize transmission wear. All-climate fluid that manages temperatures as low as -40 degrees Fahrenheit (-40 degrees Celsius) to as high as 300 degrees Fahrenheit (149 degrees Celsius)

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It's sure is thinner, noticeably so. I wondered about this also but as long as it's slippery enough it will work. I noticed right away the transmission made a reassuring click click when shifting between gears. Without any added effort the shift was also quicker. Usually the first few up shifts, mostly into second were 'stiff' till the trans had a few blocks distance on it to 'warm up', more so when near freezing but that all went away. I stopped down shifting into second until at the lowest speed when turning a corner or it would need a very firm PULL to synchronize into gear and often the gears would still grumble a little. This also went completely away. It's been almost 5 years and I'm still waiting for a downside to this stuff. Otherwise it's the best $35 I ever spent on the car.

 

I just drained the GL4 out, the drain is at the bottom so a few hours while doing something else and there wouldn't be more than a 1/4 cup left wetting the inside. I've rinsed a transmission out with ATF before by rolling it around on the lawn, then draining it. I doubt it was necessary.  

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I'm going to try this synthetic oil. Hope it work's as good as your GM Delco Friction Modified Synchromesh Transmission Oil.

 

 

Royal Purple 01300 Max Gear Ultra-Tough High Performance Synthetic Gear Oil 75W-90

 

Max Gear is recommended for use in truck and automotive front or rear differentials, manual transmissions and lower gear units of marine engines that specify use of an API GL-5 or GL-4 fluid. It is non-corrosive to soft yellow metals (brass, bronze, copper, etc.) and synchronizer safe. Specially designed to extend gear and bearing life, Max Gear provides superior corrosion protection over competing conventional and synthetic gear oils. Royal Purple engineered this ultra-tough, high performance automotive hypoid gear oil to provide maximum protection to heavily loaded gears while maximizing power throughout the drive train. Max Gear outperforms ordinary gear oils by combining the highest quality synthetic oils with Royal Purple’s proprietary Synerlec® additive technology.

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I'm going to try this synthetic oil. Hope it work's as good as your GM Delco Friction Modified Synchromesh Transmission Oil.

 

Royal Purple 01300 Max Gear Ultra-Tough High Performance Synthetic Gear Oil 75W-90

 

Max Gear is recommended for use in truck and automotive front or rear differentials, manual transmissions and lower gear units of marine engines that specify use of an API GL-5 or GL-4 fluid. It is non-corrosive to soft yellow metals (brass, bronze, copper, etc.) and synchronizer safe. Specially designed to extend gear and bearing life, Max Gear provides superior corrosion protection over competing conventional and synthetic gear oils. Royal Purple engineered this ultra-tough, high performance automotive hypoid gear oil to provide maximum protection to heavily loaded gears while maximizing power throughout the drive train. Max Gear outperforms ordinary gear oils by combining the highest quality synthetic oils with Royal Purple’s proprietary Synerlec® additive technology.

That's what I am using in my 521 4spd.... i actually have royal purple in everything on my datsun.....

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I suspect there is only one maker for this stuff and all they do is add different coloring and containers. I hope it is the same as it works wonders compared to the regular GL-4

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I run Nissan genuine GL-4 manual transmission fluid. Figured they would know what works best.

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Great thread..

 

But the tranny thing is what court my eye

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OK, thought I'd let everyone know the results running the  "Royal Purple 01300 Max Gear Ultra-Tough High Performance Synthetic Gear Oil 75W-90" in my 5- speed tranny.

It's only been a week but the tranny shifts (Up and Down) smooth as butter, it's quiet. I really thought I'd hear a little bearing wine with the synthetic but not so.

​So far so good, I haven't really hammered it while breaking in a new clutch. 

I guess I can turn the radio up now, been nervously listening to the tranny.

Gonna leave it in and see what happens.

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Check every week for wetness at the rear of the transmission, That shit is slippery!! and well squeeze out past an old seal.

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