Fred,
The oil weight is a long story:
1. The OD manufacturer originally spec'd 30 wt straight mineral oil--no EP
additives.
2. Standard Triumph originally used 30 wt oil in the early gearboxes with
or without overdrive.
3. S-T changed to specifying 90 wt gear oil in all gearboxes with or
without OD sometime in the early TR3 era. (My TR3A owners manual specifies
90 wt gear oil and the OD manufacturer's manual never changed from the 30
wt recommendation.)
4. The English TSOA club book "Technicalities" recommended using 50 wt
straight mineral oil to get around this conflict. I used a 50 wt
motorcycle oil for some time but couldn't get it anymore.
5. Over a year ago, someone on the list mentioned the NAPA 90 wt gear oil
and I switched. GL1 rated oil is just mineral oil--no hypoid EP additives.
These additives can harm the overdrive according to the manufacturer--even
though Standard-Triumph spec'd 90 wt standard gear oil, as in the
differential.
I'm still confused by it all.
Brent
>Brent, I can't tell you why the O/D has a problem, but I have never heard
>of anyone using that heavy a oil in trans., even the orig. owners
>handbook says 30 wt., just maybe after a year it has finally caught up.
|