[TR] Synthetic gear oil

[Tony Drews]

I've had a long series of e-mail conversations with Steve Yott who 
knows more about our trannies than most of us have forgotten.  He did 
some testing where he had a window into the gearbox to see what was 
happening.  One think I wasn't aware of is that different lubricants 
"foam up" more than others.  He strongly recommends the Redline MT90 
- it foams less and is compatible with the synchros and 
overdrive.  When the lubricant foams up it doesn't lubricate as well.

So, another vote for Redline MT90.  As infrequently as the lubricant 
gets changed in the tranny, the ~$15 per quart is cheap insurance.

Cheers, Tony

At 10:28 PM 12/20/2013, Randall wrote:
> > 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
>friction).
>
>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.
>
>Randall