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TR6 TR6 gear oil

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Gerry M

Gerry M

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Original specs call for GL4 (90 weight) in transmission/overdrive & diff. The only gear oil I can find in Ontario is GL5. From what I've been able to determine through some web searching is:
1. GL5 is not the same as GL4 (extra EP additives in GL5 are hard on yellow metals in transmission - not sure if diff has any yellow metals).
2. OD does not like synthetic gear oil.
3. Motor oil (as alternative to gear oil) does not provide EP protection (gear oil does).

Does any one have any recommendations/suggestions on where I can source GL4 gear oil (preferably in Ontario)?
Do the results of my web search represent the common consensus among TR6 owners?
 
You should be able to mail order the Redline MT-90, which is a GL-4 rated oil just like Triumph recommended. Although it is synthetic, it works fine in both the gearbox and OD (either A or J type). And it does actually improve the gearbox operation a bit, over either motor oil or regular GL4. Only downside I can see is the price (and to me, the improvement is easily worth the price).

Personally, I would NOT follow the recommendation for non-detergent motor oil in the article that Ken linked to. If you want to use motor oil, pick something with a good anti-wear additive (ZDDP), like Valvoline racing oil. Triumph did at one time (before about 1960) recommend motor oil, but switched away from it because of early gearbox failures.

The differential does contain "yellow metal". But it will work just fine with synthetic GL5, as long as it doesn't use the "active sulfur" additive that is usually found in conventional (non-synthetic) GL5 (and GL4). I've been using Valvoline full synthetic gear oil in mine for a long time, and it works quite well. If you can't find the Valvoline, look for something that is rated "MT-1". The MT1 rating itself really doesn't have anything to do with differential service (it's for heavy duty non-synchronized manual transmissions), but it does have a long life stability requirement that the "active sulfur" additive cannot meet.
 
Is the Valvoline racing oil their VR1 oil?
Has anyone had any experience with CRC's StaLube GL4 multi purpose gear oil - good/bad choice for tranny with overdrive?
 
VR1 is racing oil for street driven cars..They have a 'not legal for street' (whatever that means) Racing oil.
https://www.valvoline.com/faqs/motor-oil/racing-oil/
I've used Stalube GL4 in the OD tranny and differential. Other than my belief that Redline MT90 is better in the tranny, I would still be using it there.
Right now I also have something differernt in the diferential, but Stalube gave me no problems. I think if you want one fluid for both..Stalube is a good choice.
 
poolboy said:
VR1 is racing oil for street driven cars..They have a 'not legal for street' (whatever that means) Racing oil.
Click to expand...
VR1 has the full additive package to meet API requirements (and allow full oil change intervals); the "Not Street Legal" stuff does not (meaning it has less detergent and less ability to fight acid buildup). Valvoline warns against using the NSL stuff in "wet clutch" applications, which might make it a poor choice for overdrives.

BTW, CRC bought Sta-Lube in 1993, they're the same company today. Also, I've got over half of a gallon of Sta-Lube (with the CRC logo) 85W90 GL4 that I found while cleaning the garage. It's probably over 10 years old and the bottle is pretty grubby, so I was just going to pitch it. But if anyone wants it enough to pay shipping, it's yours.
 
In my TR250 with overdrive, I tried 30awg non-detergent, NAPA GL1, and StaLube GL4. I have had the best luck with the StaLube GL4. I also use that in the diff. I also use the GL4 in my non-OD TR3A. Here in North Carolina it stays fairly warm and I did not think the 30awg oil was giving enough lubrication of the transmission gears, they were making a lot of gear noise. Therefore, I much prefer the StaLube GL4. I did not try the Redline since I heard it leaks out more.
Regards,
Bob
 
TuffTR250 said:
I did not try the Redline since I heard it leaks out more.
Click to expand...
FWIW, I did not notice any more leakage in any of the 3 Triumph gearboxes (two Stag with J-type, one TR6 with A-type) that I've converted to MT-90. But they had all been rebuilt within the past 10 years or so, it might be different if you have really old seals.
 
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