[TR] Synthetic gear oil

Randall TR3driver at ca.rr.com
Fri Dec 20 21:28:09 MST 2013

> Does anyone use synthetic gear oil in the transmission and/or 
> differential of
> their TRs?  Any comments on the pros and cons of using synthetic oil?

I've been using Valvoline full synthetic gear oil in all my Triumph diffs for a long time.  The diff in my 59 TR3A was already well
worn when it came to me in 1984.  20 years and perhaps 200,000 miles later, it wasn't any worse.  ISTR I changed the pinion seal
once, but otherwise it was still working fine when the car got wrecked.

More recently, I switched to using Redline MT-90 in the transmissions and overdrives.  It improved the synchro action, and so far no
problems, at least not that I attribute to the oil.  I have had a few failures, but they clearly had other causes.

But I wouldn't use a synthetic in the transmission that wasn't designed for a synchronized transmission.  Reportedly some of the
gear oils on the market are too slick and interfere with synchro operation (which requires a certain level of metal-to-metal

Only "con" I see is increased cost.  The MT-90 in particular is worth shopping around for, as prices vary quite a bit.  Compared to
the cost of new synchro rings, it's a bargain.


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