So I put the Lucas gear oil i to the trans and road home and back to my shop, 15 mile round trip.
At the shop I could hear trans noise at idle in gear and in neutral. Very disappointing.
In my other bike I used Spectro Platinum for 6 speed but could not find any, that is why I tried the Lucas.
I called the dealer to see what was used back at the 1000 mile service and was told Formula +, so I drained and filled trans with Formula + and so far back to being quiet, 500 miles into our trip and still like it was before using Lucas.
Could it be Lucas was too thick or because it is synthetic I don't know, but I am just happy the noise is gone.
It isn't because it's synthetic. Most of the best gear lubes these days are synthetic, including that Spectro Platinum you mentioned. As for viscosity, there is no need to use anything more viscous than 80 or 90 weight GL-1. In fact, some claim the heavier lubes do not flow well in a Cruise Drive trans due to smaller passages and clearances in some areas compared to the old five speed boxes.
Formula+ is within the 90 weight gear oil spec btw, as well as the 20w50 motor oil spec. These are the specs for Formula+ for anyone interested. Harley doesn't follow normal industry conventions so you won't see something like 75w90 GL-1 on the label. Harley likes to make people think they can't substitute or make it more difficult by not giving you the industry numbers for many of their maintenance products. This product is one example.
Harley Davidson Formula+Application: recommended for heavy-duty service in manual transmissions where the manufacturer normally recommends either engine oils or GL-1 lubricants.
Specific Gravity: 0.857
Pounds per Gallon: 7.14
Viscosity, ASTM D 445,
cSt at 40°C: 168.04
cSt at 100°C: 20.10Viscosity Index, ASTM D 2270: 139
Brookfield Viscosity, ASTM D 2983,
cP at -26°C - 28,800
cP at -40°C - n/m
Pour Point, ASTM D 97, °F (°C): -60 (-51)
Flash Point, ASTM D 92, °F (°C): 507 (264)
Jerry