spottedog Posted August 24, 2016 Report Share Posted August 24, 2016 I am tired trying to get a straight answer about putting API/GL4 oil into our Datsun manual transmissions! I live in Midpines Califoria, a very small town (population 120) no stores, no nothing just a post office. I drove 42 miles to the nearest actual city and argued with the salesmen in 7 different auto parts stores about transmission oil and "gear oil" for a Datsun 5 speed trans. I got shit like "oh, we can't find Datsun in out book" or "whats a Datsun" :yawn: Three stores said "GL4 has been phased out and is no longer available and has been replaced with "GL4/Gl5" oil. One guy said "GL4 has bad chemicals in it" One size fits all. Having enough smoke blown up my ass I went home with 2 quarts of Valvoline GL4/Gl5 oil. Went home made lunch still thinking putting this modern shit in my 720 just does not feel right. Then I rembered I have a friend back in the bay area that works for a oil refinery in Richmond so I called him, he said he would call me back. He is a "92F Petroleum Supply Specialist" He called me back and told be no, don't put that crap in your truck! He asked if I have heard of Oakhurst (another hick town 32 miles further up in the Sierra) He set it up so I could go there and buy "the real deal" oil that they had in stock. Sta-Lube SAE 85W90 Hypoid Gear Oil APL/GL4 For manual transmissions, not corrosive to non ferrous copper, bronse, bearings or bushings. Extends life of gear teeth. Since 1933 (83 years?) :thumbup: Product number SL24239 $64.62 a gallon ($35.29 with my firefighters discount) Used by CalTrans equipment, the State owned outfit that maintains all the roads in California, and the Military. Sta-Lube and CRC are the same company. Expensive, but I bet cheaper than rebuilding my trans. Napa was where he sent me, the manager said they keep it in the back room not on the shelves, just ask for the part number. He also said Harly guys com in and buy it. :confused: Quote Link to comment
banzai510(hainz) Posted August 24, 2016 Report Share Posted August 24, 2016 I know what Datzenmikes says GL4 But I just run what they sell as I need it now as better than no oil in trans 1 Quote Link to comment
Doctor510 Posted August 24, 2016 Report Share Posted August 24, 2016 Royal Purple or Redline MT90 1 Quote Link to comment
Lockleaf Posted August 24, 2016 Report Share Posted August 24, 2016 Yeah. I work in the auto parts industry for O'Reilly. If not for my time working on datsuns I would never have learned about the all important "yellow metal safe" issue. I was taught in the company exactly what you were told, gl5 is just an update. That being said, we stock a pentosin gl4 75-90 at many stores, apparently used by a bunch of euros. But it's $25 a litre. Quote Link to comment
HRH Posted August 24, 2016 Report Share Posted August 24, 2016 Says the NAPA guy: GL4 doesn't have active sulfur, which pits brass/bronze. Datsun has bronze synchros, hence, over time, GL5 gear oil WILL pit them. It won't happen instantaneously. You have several options. Stalube makes a 85-90ish GL4 gear oil still which is sold at NAPA. Royal Purple gear oil is yellow metal safe. Redline MT90 is yellow metal safe. Or, you can run regular motor oil in your transmission and change it more often. 10w40 is a good weight. I run motor oil in all my Datsun transmissions, don't have any issues. Been running them for 3 years or more. Also much less expensive than gear oil. Autocross car has motor oil in it too. Aside from having 160k on the transmission (synchros grind at 6500+rpm anyway) it works fine everywhere else or if driven "normally." Also, 40 weight motor oil is almost exactly the same viscosity as 85-90 gear oil. Difference are the EP additives. (Extreme pressure) Quote Link to comment
]2eDeYe Posted August 24, 2016 Report Share Posted August 24, 2016 GL5 says right on the bottle that it is corrosive to bronze synchros. 2 Quote Link to comment
Draker Posted August 24, 2016 Report Share Posted August 24, 2016 Why drive... when you can amazon. https://www.amazon.com/CRC-SL24229-GL-4-Multi-Purpose-Gear/dp/B000KKHO86/ref=sr_1_2?ie=UTF8&qid=1472063179&sr=8-2&keywords=sta-lube+gl-4 1 Quote Link to comment
Draker Posted August 24, 2016 Report Share Posted August 24, 2016 That is.. unless you like the feel of smoke up your ass. Or you have hours to waste. Quote Link to comment
datzenmike Posted August 25, 2016 Report Share Posted August 25, 2016 GL-4... This is what using GL-5 will do. Not right away but it will slowly tarnish and erode the copper in the alloy.... All EP (extreme pressure) oils have an anti scuff sulphur additive in them. The sulphur bonds with the top layer of atoms and forms a brittle hard wearing surface. This is good on steel alloys but copper is very soft and under even a light load this layer will crack off like a layer of ice on a pond. The next layer will form and again crack off and so it will continue. GL-4 has roughly a 4% anti scuff component that the brass synchro rings can tolerate without harm to them. GL-5 has a 6% anti scuff component in it and this is the problem. It's way too strong a mix and it will attack the copper. A 2% difference doesn't seem like much but it isn't 2% more. Six is 50% more than 4, if you think about it. Transmission oil should be changed every 30K miles or 5? years. GL-5 is used in primarily in differentials where the increased level of sulphur additives is needed. Yes GL-5 is much better than GL-4 and a definite up grade in protection, but beside the eroding of the copper alloys it simply isn't needed in our transmissions as the gears work much differently than a differential. I may be wrong but Redline and Royal purple... are they synthetic? The problem with synthetic oils is they were developed long after our transmissions were designed. To put it simply these old transmissions never had to deal with how thin and slippery synthetics are and they may begin leaking at the seals and more likely on older worn seals. If you run it and there is no leaking or wetness near the driveshaft that's great. Just watch and check regularly. I had a synthetic in a transfer case and the rear driveshaft seal leaked so I replaced the seal and it was fine. Then the front started leaking so replaced it and then the top input. Once I had new seals it was fine. I'm currently running GM Delco Syncromesh oil and the tail is damp even with a new seal. I drove to Canby and put about 2K miles on her last and this year when I checked the level it was still ok. I think it wise to just keep an eye on it unless running 80w90 GL-4. 2 Quote Link to comment
Longtooth Posted August 25, 2016 Report Share Posted August 25, 2016 Has to say yellow metal safe. Royal purple makes it. 1 Quote Link to comment
racerx Posted August 25, 2016 Report Share Posted August 25, 2016 I would stick with what our manuals says. Found mine at winchester auto. Yes, u might have to call around or shop on line but not worth getting wrong type of fluid for tranny or rear end. Quote Link to comment
datzenmike Posted August 25, 2016 Report Share Posted August 25, 2016 You can run just about anything in it for short term, you know to get you home. Even GL-5 in a pinch, just drain it later and get the right stuff. ATF works but is very thin. It works to lubricate all the gears in an automatic but then again it also has an oil cooler. Engine oil around 40w is the same viscosity as 80-90w gear oil but does not have the EP (extreme pressure) rating. Again, in a pinch it's fine but with GL-4 certainly available, it's not a substitute for it.. 1 Quote Link to comment
scooter Posted August 30, 2016 Report Share Posted August 30, 2016 +1 on the gm synchromesh. Makes anything shift like butter with no noise. No grinds with 7500rpm shifts, not hard to shift when its cold. I wont use anything else in my trannys now. Its expensive shit though. With a new seal and a new yoke, i can see that the yoke isnt dry, but its not very oily to the touch, and its not dripping or flinging.. Theres a stripe from u joint grease flinging but thats about it. For diffs i usually just use castrol hypoid... Quote Link to comment
datzenmike Posted August 30, 2016 Report Share Posted August 30, 2016 I think I paid about $34 CDN for2 liters, which is enough for a 71B. Quote Link to comment
MikeRL411 Posted August 31, 2016 Report Share Posted August 31, 2016 Most synthetic motor oils are natural gas derived, One up for domestic production, not so sure about longevity given doubts about additives. Remember when Penzoil bragged that they were Pennsylvania oil field stock derived and that the "greenish" color was due to the sulpher content? Quote Link to comment
MicroMachinery Posted August 31, 2016 Report Share Posted August 31, 2016 That is.. unless you like the feel of smoke up your ass. So THAT'S where he's been.. 1 Quote Link to comment
racerx Posted August 31, 2016 Report Share Posted August 31, 2016 spottdog, Amazon carries them. You don't have to go far and look. Maybe even Jegs or summit carries them Quote Link to comment
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