GL5 in a TR6

[Dave@Moon]

I bought a Triumph TR6 this past summer which was slightly low on gear lube in the transmission. Without thinking I grabbed some GL5 85W-90 from the garage and topped it off. It was about a 3/4 pint low (out of 2.4 pints).

Since then I've read a few times online that TR6 synchros and bushings are made of a particularly soft brass. Also that GL5 has additives that are particularly corrosive to soft brasses, and that only the earlier GL4 rated gear lube should be used. Otherwise the synchros and bushings wear excessively & give out.

Has anyone had this experience? Is this an old wives tale or true? And would a roughly 30/70 mix of GL5 to GL4 be problematic this way?

[Peter J.Heizmann]

Hi, Dave. Hope all is well.

Personally, I have little to contribute to your questions, except, you may want to try the Vintage Triumph Register www.vtr.org

Scroll down to the very bottom of their home page and you will see Technical Help. I just clicked on it and for the TR6 they note one Mark Pelham, Charleston, Ill (<span style="color: #3366FF">slimsqt@ma.rr.com</span>) as the technical guy for the TR6.

Regards,

Peter...

[Dave@Moon]

Hi Peter,

All is well enough here. My '75 needs rebuilt carbs and I have to wait for my arm to get better (tendonitis) before I can get it back on the road. The '70 is still waiting for me to get the garage in order. I hope all is well with you!

(The up side for that is I find better parts for it the longer I wait. I just got a set of Lucas European headlights this week (<span style="font-style: italic">rare left-hand drive type</span>). They're a seperate bulb/reflector type with an additional minibulb that makes the headlights glow with the parking lights the way the early '50s VWs did. That'll look cool on a midnight blue car! )

I'll probably just go ahead and change the fluid to be safe. For one thing I don't know for sure it had GL4 in it to begin with, but the car was restored in the mid-1990s (and then hardly ever driven, which is why the carbs let go) and that's probably the case. I don't think I'll bug Mark for something as trivial as 2 pints of gear lube, but thanks.

Mostly I posted this here to see if the GL5 information I've been reading on the British forums is correct. It's a pretty universal condemnation on those forums, but it has never been mentioned here. It appears nobody has any contary information here either.