Jump to content

I struck oil!


Recommended Posts

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:

Link to comment
  • Replies 16
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

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.

Link to comment

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)

Link to comment

GL-4...

synchroLarge.jpg

 

 

This is what using GL-5 will do. Not right away but it will slowly tarnish and erode the copper in the alloy....

syncros%20GL5-1.jpg

 

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. 

  • Like 2
Link to comment

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.. 

  • Like 1
Link to comment

+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...

Link to comment

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?

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.