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Triumph TR6 - Brassy Fines in Gearbox and Overdrive

During the 75,000 miles since my restoration in 1990, I have always used Valvoline 20W50 engine oil in my gearbox with overdrive. This was the recommendation from Ken Gillanders at British Frame and Engine in Temple City, California. I have never had any mechanical problems caused by this oil.

I drain the oil every 3,000 miles. It comes out looking like it went in. Except, there is a brassy looking paste in the oil that I drain from the gearbox and also later in the bottom of the huge brass plug to drain my overdrive.

1,600 miles ago, I changed to Castrol 80/90 Hypoy GL4 oil. Will I see less of these brassy fines next time I drain it ?

Do others get this ?

Any explanations ?

Is it getting into the ball and needle bearings to cause pre-mature failure ?

Don Elliott, 1958 TR3A
Don Elliott

Hi Don,
I would be very concerned about using an engine oil which is lighter weight than the manufacturer specs for gear oil. I have only used the 80/90 gear oil in my gearbox as probably every other tr6 - or at least those that have had the oil changed sinced the 1970s! Interestingly I think the manuals spec a heavier weight than 80/90 however I dont think it is readily available.

I dont know for sure but the brassy stuff from the gearbox might be wear from the synchros.

Definitely the syncros. They are the only brass components in there.

Don, As long as the amount of brass is small you should be OK for a while. Running the engine oil is not really a problem according to most sources. I too was running a lighter oil from Mobil but have gone back to Red Line 80-90. There are a LOT of brass parts in the assembly. There are the 4 synchros (maybe 3 in your case). There are the brass bushings for 1st, 2nd and third gears on the mainshaft. Lastly you have two brass surfaced thrust washers on the countershaft. Now in the overdrive again, all kinds of brass bushings and thrust washers which wear out like crazy!!! If your overdrive has the 75k on it I would almost bet that the thrust washer between the sun wheel and one way clutch is about 1/2 as thick as a new one! The t-bushes on the main case of the overdrive also wear a lot. As long as things are working and not a lot of extra noise is coming from the box then leave it alone and continue to change the oil. If you start seeing brass pieces and not powder then it is time to overhaul. I have not seen where the brass has caused any definate wear on the other bearings etc. Luckily the brass is much softer and the steel wins that battle. The biggest failure on your setup will be the countershaft (laygear) and the sunwheel bushings in the overdrive. Steve Yott
Steve Yott

Thanks Steve and others. Being a TR3A owner, I have asked this question on the TR3 site up a few lines as well, and have some interesting responses there too.

Ken Gillanders who just did a write up in the latest newsletter for the TRSC (Triumph Register of So. Calif) in the TRSC TRibune, is still very positive about the Valvoline 20W50 - as I am. But I've switched to see if there will be any change.

Ken is starting another long test on the Red Line, but he says it's too early to report.

When I bought my TR3A (brand new in 1958), I used what S-T recommended - straight 30 weight (non-detergent) oil in the gearbox with overdrive and only got 40,000 miles before having to change the layshaft and all the bearings. Then in 1998, while doing my restoration I had to do it all again. So with the Valvoline 20W50, I feel it has been good, to me getting over 75,000 miles with no problem except a bit of brassy fines when i drain it.

But it has popped out of 2nd gear 5 times in the last 2,000 miles, so I too, suspect end face wear on the top-hat bushes as well as from the synchros.

Don Elliott, Original Owner, 1958 TR3A
Don Elliott

With the popping out of 2nd. I would bet that the 2nd. gear top-hat is broken, like they all seem to do! Revington TR has a couple of interesting repair kits available. One is a kit of steel bushings for the mainshaft (late TR6 style) for our earlier gearboxes that they say ends all of that trouble. They also have an uprated layshaft kit that has three open cage needle bearings that they use on the race and rally cars, also very durable. These kits fit right into our early boxes with no other mods. Other than that in my early days I used bunge cords to hold the gear lever! Steve
Steve Yott

Hello all: I have a 1956 TR3 w/ an all synchromesh TR4 transmission. After the car has been up to operating temp for awhile, it gets more difficult to change gears. Coming out of a gear is ok, but getting into the next one takes a second.(and some effort)
When it's cold, it's smooth as silk.
I purchased the car in Nov. of '02, and all fluids are fresh. I use Hypoy 80/90 GL4 in the gearbox. I've yet to check the fluid level since being on the rosd, but there are no leaks, so I'm assuming it's ok.
I've spoken to the folks on the TR3 site, as well as mechanical friends, but it's still a mystery.
Any ideas? Thank you for any input you might have.
Mike Gambordella 1956 TR3
Mike Gambordella

Almost has to be the synchros does it not Mike?
This sounds related to the viscosity of the lube being so high when cold and considerably lower when warm.
At least that's my .02 worth.

Jim Deatsch

Mike, I wonder if your clutch is fully disengaging when it is warm you may want to check fluids on that side. Don E. can be a big help here if he isn't on some 3000 mile tour with his tr3. The 3 has a common reservoir for brakes and clutch and I am not sure if the release arm is the same as on my tr6(multiple holes to push the clutch further) but maybe you need more release when everything gets loose. Maybe I try to think simple things first. Check your reservoir first and make sure you add the right fluid, check your hydraulic fittings 2nd and while the beast is airborne check your tranny fill if it starts to leak when you remove the fill plug put it back in quick. I find that is an indicator that it is ok. (It's a bitch to get that out of your hair). Good luck and enjoy try to make it till Oct. then pull it apart.
72 tr6

Thanks, Jim. I'm not sure how worn the synchros are
(or any other parts) as I've not had the gearbox apart. It does downshift w/o any problems, though. Perhaps this is due to the additional engine revs given between throws on downshifts, but not on upshifts. Time will tell...
Thanks again.
Mike Gambordella


I have driven almost another 3,000 miles with the Castrol Hypoy 80/90 GL4 gear oil in my gearbox. Today I drained it out and found the same amount of brassy or bronze flakes and fines as with the Valvoline 20W50 engine oil that I have been using for 72,000 miles with an oil change every 3,000 miles.

Ken Gillanders told me that the Hypoy GL4 oil will soak into bands in my overdrive. So I have gone back to the Valvoline 20W50 (Racing) oil for my gearbox with overdrive.

Don Elliott, 1958 TR3A

Don Elliott

This thread was discussed between 14/08/2003 and 04/09/2003

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