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Posted By: Hermit Bronze-friendly gear oil recommendation? - 05/17/18 12:12 pm
I've been to five auto parts stores, three big-box stores, and two ATV shops looking for bronze-friendly gearbox oil. No luck.

So it's down to ordering gear oil online. Amazon lists two gear oils that say they are yellow metal safe, and I'm wondering if anyone has experience using either one of these products, or has another recommendation. If they SAY the product is yellow metal safe can I depend on that?

Note that the Red Line product is "full synthetic". Is that suitable for '69 T120R gearbox?

PJ1 11-90 Hypoid 90W Gear Oil, 1 L
https://www.amazon.com/dp/B0036GK8R...Q3029&psc=0&ref_=lv_ov_lig_dp_it

Red Line (50304) MT-90 75W-90 GL-4 Manual Transmission and Transaxle Lubricant - 1 Quart
https://www.amazon.com/dp/B000CPCBE...Q3029&psc=1&ref_=lv_ov_lig_dp_it


Also, is all fork oil synthetic? That's all I seem to be able to find. Is sythetic fork oil ok for 60s vintage forks?

Posted By: htown Re: Bronze-friendly gear oil recommendation? - 05/17/18 4:13 pm
You want to use the Gear oil not the Transmission Fluid. The latter has additives that your GB won't like. Synthetic or mineral doesn't matter. I've used both. That PJ you show says it is for motorcycle driveshafts. Not sure that's what you want. Almost all modern gear oils are compatible with yellow metal.
In theory any gear lube of the correct weight than labeled MT is ok... I use Redline 75-90 in my race Triumph...You may find it contributes to a bit more crunch going into first gear than non synthetic oils....Brad Penn Classic gear oil is a GL 4 that works fine, I have used it ...
Now for my experience...I know guys using GL5 oil in older stuff with no problems...Anyone have proof that the GL5 erodes yellow metal , like many situations, not just one example ? A lot of this comes from older car transmission with brass/bronze synchronizer rings...It's not that the oil erodes the metal, the additive package in GL5 oil is too slippery for older synchros to do their job...Triumphs don't have synchros but they do have a few yellow metal thrust washers and a bearing...
I thought that you could only use oil up to GL-4. I use the cheapo comma brand of mineral GL-4 oil in the box but it is fine.

Dave
Posted By: Sam Re: Bronze-friendly gear oil recommendation? - 05/17/18 5:40 pm
I use GL1, 90 wt mineral oil from tractor supply, yellow metal friendly.
Posted By: htown Re: Bronze-friendly gear oil recommendation? - 05/17/18 8:42 pm
I use Lucas oil synthetic 75w90 gear oil. Says for diffs and gearboxes. Buy it at Autozone. You might want to go with the multiweight in your location if you do much cooler weather riding.
My Velo has yellow metal in the transmission. I grew up with twins and triples and was used to using hypoid in the trans. The book for the Velo said to use 40 wt. I couldn't believe at the time that was a good idea. Somewhere I was advised that you didn't have to worry about hypoid effecting yellow metal as long as it was a modern hypoid, so that is what I used for 20 years. Last year I read on the Velo forum a number of folks claiming that they were getting a yellow sheen when they drained the oil if they used hypoid. I never had a yellow sheen, but I was in the midst of trying to make the shifting sweeter. So I contacted Bel-Ray. They told me that I should avoid hypoids, old and new, in transmissions with yellow metal. They also said the Velo would be fine with 40 wt, but they recommended their Gear Saver 80 wt, which is a non hypoid. I put that in and have been using it ever since without issue. I continue to use Valvoline hypoid in my Trident, my BSA twin, my Norton twin, and my unit singles.

Ed from NJ
I think this is one of those subjects people worry about unnecessarily. If it says EP80 or EP90, and it's a well known brand, bung it in, it'll be fine. As for whether modern oils will work in machinery made before they were invented, it seems an odd question. Old machinery worked OK with the simple oils that were available back then, so with the better stuff available now, they'll work at least as well,if not better.
Posted By: Hermit Re: Bronze-friendly gear oil recommendation? - 05/17/18 10:43 pm
htown - yes, I see now - I had the transmission lube, not the gearbox.

Hillbilly bike - I found the MT-1 designation (https://www.oilspecifications.org/api_gos.php) - it provides "protection against the combination of thermal degradation, component wear, and oil-seal deterioration, which is not provided by lubricants in current use meeting only the requirements of API GL-1, 4, or 5." So my understanding would be that I'd have to find a bronze-friendly oil and if it happened to be MT-1 that would be icing on the cake. Redline 75-90 and Brad Penn Classic - I'm taking notes.

Sam - GL-1 90W for tractors sounds promising. Gl-1 MT-1 would seem like the ideal ticket. There is a Tractor Supply chain store within striking distance so that's a possibility.

Dave - it was always my understanding, and I'm probably wrong, that GL4 was generally ok, but GL5 could be a problem. I always used 85W-90 GL-4 and never had a problem, but last summer I think I might have used some GL-5 that was lying around.

Anyway, I was surprised this winter when I drained the gearbox and then pulled off the outer cover after finding bronze in the oil. Go to this url and click on the fourth and fifth thumbnails from the top and you'll see what I found. When I pulled everything apart I found those little bronze flakes everywhere and in everything, but 90% of it settled between the inner and outer covers and was trapped there
.
www.hermit.cc/tmc//bb/2018/wtd_1/index.htm

Initially I thought I'd spun the drive side layshaft thrust washer, and it had moved (i'd driven the locating peg down) a little bit, but the only damage to it was a scrape on the backside, about a third of the way around - not enough it seemed to account for all the bronze pictured in the photos.

I measured the thickness of the thrust washers and they were both still in spec. I took high gear and layshaft gear with bronze bushings to a machinest and showed him the specs and he said they were ok. Was the gear oil I used unkind to the bronze in the gearbox? Or was it something else? (Probably something I did according to the odds).

Every gear oil I've looked at around here is GL-4 AND GL-5, and after replacing all the gearbox bearings after just one year I'm a little paranoid about suffering a repeat, and thus my heightened concern about using an appropriate product.

Ed from NJ - I have heard it said not to use hypoid oil, but it seems to work ok for you in your Brit iron.

I guess at the very least I'm going to look for a product that specifically states that it's ok for bronze. Not so easy to do online. My next move will definitely be to visit the Tractor Supply store.

Thanks to all posters for your input!





Originally Posted by Hermit
htown - yes, I see now - I had the transmission lube, not the gearbox.

Hillbilly bike - I found the MT-1 designation (https://www.oilspecifications.org/api_gos.php) - it provides "protection against the combination of thermal degradation, component wear, and oil-seal deterioration, which is not provided by lubricants in current use meeting only the requirements of API GL-1, 4, or 5." So my understanding would be that I'd have to find a bronze-friendly oil and if it happened to be MT-1 that would be icing on the cake. Redline 75-90 and Brad Penn Classic - I'm taking notes.







From the American Petroleum Institute...".The designation API MT-1 denotes lubricants intended for non-synchronized manual transmissions used in buses and heavy-duty trucks. Lubricants meeting the requirements of API MT-1 service provide protection against the combination of thermal degradation, component wear, and oil-seal deterioration, which is not provided by lubricants in current use meeting only the requirements of API GL-1, 4, or 5."
Sounds perfect for a Triumph, LOL

There was a Triumph with very high miles and the owner ,late Pat Owens I think, said the trans wasn't worn because he used some sort of very thick lube...I like what Nick L said.... :bigt
The early EP gear oils used a sulphur based additive which in the GL5 concentrations attacked bronze, but the oil had to be up near 100c to be an issue ref Glacier Metals engineers design manual, the additives have also now changed.
Hi Hermit, I contacted Mobil about synthetic gear oil & they say ok for yellow metals. I also contacted Redline about the Heavy Shock Proof V-twin gear lube. The pink stuff. Could not find it in print though.

In 70s I used Castrol gear oil 90w as I got free from work. Never thought about bushing problems.

Then when got bike out of storage I read about yellow metal issues.

I put in Sta-Lube Multi Purpose Hypoid SAE 85w90 API GL3, GL4. Specifically states on back of bottle not corrosive to copper, bronze or other non ferrous alloy bearings & bushing.

I used the Sta-Lube for some time, then switch to Redline V-twin. The V-twin gave smoother gear pedal motion, but much worse clunk into 1st & other gears as well. Odd since it is supposed to quite engagement on Harleys.

Switched back to Sta-Lube & was back to normal.

Sta-lube is sold at CARQUEST (Advance auto parts), & many independent parts houses in my area east of San Francisco. 1qt or 1 gal depending on store.

How good is Sta-lube? I really don't know.

The pink Red Line V-twin is the exact same oil as Heavy Shock Proof per Redline rep. It foams like mad & leaves a gooy pink residue in gear box. Made it very easy to diagnose gear box seal leak though. However seems very slippery & for sure allowed gears to rotate longer & more freely with clutch pulled at stand still. I didn't like that at all. But maybe the gears would last much longer?
Don
...GL4 is not necessary for most situations. You only need 90 oil, also 85/90. My 48 500 still kicking right with these.
The box is not the engine...
That's what I'm thinking Reverb, something very basic. Will get to tractor supply next week and hope to find something there.

I'm also considering tossing a couple of old thrust washers and bushes into some glass jars with a couple of GL-5 products and see what happens over time.
In the order of things, I don't think it's worth thinking about. I've always used cheap halfords classic 20/50 in all 3 areas. It is cheap enough to replace frequently, which I think is more important than how many GL whatever molecules are available.
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