Oil for Muncie 4-speed
04-13-2017, 09:30 AM
#1
Intermediate
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Oil for Muncie 4-speed
What is everyone using in their Muncie transmissions. I can't find any 80/90 conventional Gl4 oil. Synthetic will start to leak sooner and Gl5 is bad on the synchronizers. Thank you for any help.
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04-19-2017, 11:05 AM
Instructor
So here is my take. Yes in "theory" GL5 can corrode yellow metals but only if you boil the oil. The only corrosion you will get is a tarnished ring. I have never seen damage to rings using conventional Gl5 fluids.
You will not get corrosion. If anything its a play on words. The ring can just turn to a black color. I've seen black rings typically when transmissions get overheated, possibly with a GL5. But they still work, but just were discolored.
Marketing 101. If you can get someone to switch to your brand because it is better it may be possible you will use their engine oils and diff oils as well. That's how it works. As a result you will notice that in the past 2 years oil companies have come up with specific GL4 oils now to jump in the game. It's this perpectual banter on forums that helps market it even further with people cutting and pasting data sheets and feeling smart about their internet research.
I've built 1000's of transmissions and never seen any proof of this problem. I've always recommended Valvoline conventional gearlube or Royal Purple Max 75wt because both have worked well especially Royal Purple in our endurance transmissions which are non cooled and subject to extreme heat.
However because of forum banter people are asking for GL4 because of what they read on forums. So, I carry the Brad Penn GL4 as well as the Driven Racing Oils GL4. I have done extensive testing with both oils and drivers say they feel smoother shifting with the Driven oil GL4
When it comes to motor oils, you are basically using a lighter weight oil and will feel the benefits from it in terms of shifting and cold weather. You won't see it used in Nascar but you will see lighter weight "qualifying" oils used only for that short run. Transmission journal clearance, gear backlash , and oil flow dynamics all come into play when choosing the right viscosity. Example the T5 5 speed used conventional Dexron III. People who decided to use 90wt lube in them usually ended up with burn't up pilot needles because the higher viscosity couldn't flow through the small oil bleed holes on the input shaft. In regards to motor oils being used, I've noticed that units where people used a 50wt oil ended up with more scuffing on the gear teeth in race applications compared to Royal Purple 75wt Max or the Driven GL-4 which both show no signs of galling or scuffing. Keep in mind these transmissions are getting hot and running sometimes for 6 hours at 100 plus MPH speeds.
Take care,
Paul Cangialosi
GearBoxVideo.com
You will not get corrosion. If anything its a play on words. The ring can just turn to a black color. I've seen black rings typically when transmissions get overheated, possibly with a GL5. But they still work, but just were discolored.
Marketing 101. If you can get someone to switch to your brand because it is better it may be possible you will use their engine oils and diff oils as well. That's how it works. As a result you will notice that in the past 2 years oil companies have come up with specific GL4 oils now to jump in the game. It's this perpectual banter on forums that helps market it even further with people cutting and pasting data sheets and feeling smart about their internet research.
I've built 1000's of transmissions and never seen any proof of this problem. I've always recommended Valvoline conventional gearlube or Royal Purple Max 75wt because both have worked well especially Royal Purple in our endurance transmissions which are non cooled and subject to extreme heat.
However because of forum banter people are asking for GL4 because of what they read on forums. So, I carry the Brad Penn GL4 as well as the Driven Racing Oils GL4. I have done extensive testing with both oils and drivers say they feel smoother shifting with the Driven oil GL4
When it comes to motor oils, you are basically using a lighter weight oil and will feel the benefits from it in terms of shifting and cold weather. You won't see it used in Nascar but you will see lighter weight "qualifying" oils used only for that short run. Transmission journal clearance, gear backlash , and oil flow dynamics all come into play when choosing the right viscosity. Example the T5 5 speed used conventional Dexron III. People who decided to use 90wt lube in them usually ended up with burn't up pilot needles because the higher viscosity couldn't flow through the small oil bleed holes on the input shaft. In regards to motor oils being used, I've noticed that units where people used a 50wt oil ended up with more scuffing on the gear teeth in race applications compared to Royal Purple 75wt Max or the Driven GL-4 which both show no signs of galling or scuffing. Keep in mind these transmissions are getting hot and running sometimes for 6 hours at 100 plus MPH speeds.
Take care,
Paul Cangialosi
GearBoxVideo.com
04-13-2017, 09:38 AM
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Find a store that sells farm tractor parts or big rig parts
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nasteve (04-13-2017)
04-13-2017, 09:45 AM
#3
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Sta-Lube. NAPA has it.
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nasteve (04-13-2017)
04-13-2017, 11:03 AM
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nasteve (04-13-2017)
04-13-2017, 11:54 AM
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The original spec was Mil-L-2105D. This mil spec was cancelled about 20 years ago and replaced with the SAE 80W-90 GL-5 API commercial spec.
Boutique oil vendors promulgate the "yellow metal corrosion" myth to sell you their overpriced products. It's true that the EP additive in GL-5 (which is what causes the pungent odor) can corrode brass, but it's only an issue at temperatures well above the operating temperature of the oil.
I have asked many times: Has anyone ever found corrosion inside and old manual transmission? No one has ever said yes... only normal mechanical wear.
SAE 80W-90 GL-5 is commonly available at any auto parts store and brand is irrelevant. Just make sure the bottle has the "API donut" that states SAE 80W-90 GL-5.
Duke
Boutique oil vendors promulgate the "yellow metal corrosion" myth to sell you their overpriced products. It's true that the EP additive in GL-5 (which is what causes the pungent odor) can corrode brass, but it's only an issue at temperatures well above the operating temperature of the oil.
I have asked many times: Has anyone ever found corrosion inside and old manual transmission? No one has ever said yes... only normal mechanical wear.
SAE 80W-90 GL-5 is commonly available at any auto parts store and brand is irrelevant. Just make sure the bottle has the "API donut" that states SAE 80W-90 GL-5.
Duke
Last edited by SWCDuke; 04-13-2017 at 12:37 PM.
04-13-2017, 12:13 PM
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Yep, Sta-Lube.
You can buy it on the Internet... or go to NAPA.
GL4 only rated.
https://www.finditparts.com/products...DAUaAu2A8P8HAQ
You can buy it on the Internet... or go to NAPA.
GL4 only rated.
https://www.finditparts.com/products...DAUaAu2A8P8HAQ
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nasteve (04-13-2017)
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04-13-2017, 01:25 PM
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SWC Duke is an engineer, I believe. I am not. However, I've been in the auto industry for almost 40 years, and into vintage and antique cars that long. I have seen and handled many, many gearboxes, rear ends, transfer cases, etc. I have a large group of automotive friends and professionals who are in the industry. I have done research. Like Duke, I have never, ever, not even once, seen brass degraded by gear oil of any type. Not even in my 102 year old Ford. The only thing I've seen happen to brass is that spun brass (old car and truck headlamps) tend to fatique and stress crack after about 90-110 years. That's it. But you can immerse them in any gear oil you want for as long as you want and you won't corrode a thing. I have yet to see an objective experiment or test that was actually performed to show how caustic GL-5 is to brass. Nobody else seems to have, either.
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nasteve (04-13-2017)
04-13-2017, 02:03 PM
#11
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GL-5 MT-1 is the designation you want to look for. Valvoline and others make it. Check your autoparts store. This is the oil that Autogear who makes the newer Muncies recommend. They specifically say to not use GL-5 without the MT-1 designation
Last edited by GCD1962; 04-13-2017 at 05:16 PM.
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04-13-2017, 07:34 PM
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04-13-2017, 07:46 PM
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Boutique oil vendors promulgate the "yellow metal corrosion" myth to sell you their overpriced products. It's true that the EP additive in GL-5 (which is what causes the pungent odor) can corrode brass, but it's only an issue at temperatures well above the operating temperature of the oil.
04-13-2017, 10:20 PM
#19
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I think Autogear has a little more experience with what certain oils do and do not do, than you believe. They say nothing about corrosion but rather how the syncros wear with the certain oils.
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GTOguy (04-14-2017)
04-14-2017, 05:56 AM
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big rig trans use the style synchros as our old Muncies and most of them can get 750,000 miles out of them before a rebuild and they are just using a GL-5. Why are you guys worried about it?