Anyone know if Spectro 75W-140 6-speed transmission oil is on the street yet? If so, where can I get it? I see it advertised in magazines but can't find it anywhere online and Spectro's website pretty much sucks for providing any useful information.

I want to try it to see if it'll dampen the gearbox noise my '07 has in 5th & 6th gears.
Original fill H-D oil was pretty good & noises were hardly noticeable. Dealer put Amsoil in all three holes at 1K service & tranny noise is much louder now. The Spectro oil says it specifically addresses tranny noise, so I figured I'd give it a shot before going back to the factory H-D oil.

Thanks!

 

Engine oil has no business in the transmission....I don't care what brand it is. Amsoil, SYN3, and even Mobile 1.....no business in there.

Gear Lube is the only thing that should be in there. You are looking for Spectro.....I do not know where to find it, but you'll be better off with it than any engine oil.

 

If you want to quiet that trans down put Amsoil 75W140 in. My won put Amsoil 75W110 oil they just came out with lately and it was considerably quieter than the HD oil but it was harder to find neutral with it so he put the 75W140 in and it was a improvement over the 75W110. The heavier 75W140 seems to work better in these trans. Had good luck with BelRay oil in the past. There are lots of better oil out there than the HD oil.

 

I agree with EVORider that a gearbox should be lubricated with gear oil. I switched to Royal Purple 85w140 and it made a big difference in the 6-speed noise issue in my '07 SG. I feel that any heavy synthetic gear oil will perform similarly, so you might want to try something that's easy to find, like Mobil 1.

 

Thanks for the responses.
The tranny does have gear oil in it- it has dealer-installed Amsoil. That's why I asked about the Spectro oil- the Amsoil isn't working for me.

If I can't find the Spectro I'll likely just go back to the H-D oil that was in there from the factory. 5th gear whine was barely noticeable and there was no 6th gear rattle can noise with the OEM oil.
I've also heard a lot of good things about Royal Purple as Iclick mentioned, so I may give them a try.

I emailed Spectro yesterday & asked if the Platinum 75W-140 6-speed tranny oil was on the market yet- hopefully they'll get back to me with an answer soon...

 

If your dealer installed Amsoil engine oil in the tranny and Amsoil is easy for you to obtain, try their heavy gear oil of similar viscosity (??w140). I think it is more a factor of the viscosity than brand. FWIW, a friend installed Torco ??w140 in his '94 Dyna and claims it quietened his 5th-gear noise in that old Evo tranny.

 

As mentioned- the tranny already has Amsoil gear oil in it. My dealer carries 75W-90 & 75W-140 gear oils and I saw them putting it in, I just didn't note the exact viscosity at the time. (Probably the viscosity the manual calls for.)
The engine got Amsoil 20W-50 engine oil.

 

The manual calls for Formula+, which isn't a gear oil and its viscosity is about 10w30. The 75w90 gear oil is the equivalent of a 10w30 engine oil, and the 85w140 about a 20w50, so there is a big difference between the two. I had RP 75w90, then changed to 85w140 and noticed a big difference, and I wouldn't blame Amsoil for not working up to expectation if you're not sure which was installed. Some have tried other ??w140 gear oils in 6-speed trannies and haven't reported as good a result as I have received, but I still think it is a factor of the viscosity than brand. I could be wrong, but I don't like making statements that the oil I use is "the best," as there's too much of that subjective practice on these forums already, and I don't know for sure if it is the brand or viscosity, or a combination of the two, that made the difference.

 

100% true. Glad I'm not the only one who feels that way.
25+ years of wrenching professionally has provided me with an experience base to draw on and I do have my own favorite lubricants, but I'm not about to tell everyone they are "the best."
In this case, "the best" will be whatever quiets my transmission down.

I may just blow off the Spectro and try the R-P that you're using- if I can find a vendor around here. If it works as well for me as it works for you I'm good to go. If not, I'm only out a few bucks and I can always go back with the H-D recommended oil- it did a pretty good job of quieting the noises...

 

try www.ironpony.com for Spectro oils