has anyone tried "Spectro Heavy Duty Platinum 6-speed Transmission Oil"
in a 5 speed trans? might be overkill, I dunno... I don't think my 5 speed trans is smart enuf to know if I put a '6 speed' oil in it...

I'm running Redline shockproof heavy in my trans now, but I ride a lot in colder weather and finding neutral is sometimes problematic. thought I might try a little 'runnier' gear oil.

http://www.spectro-oils.com/products...oducts=cruiser

I searched here and didn't find anything specific to this product.

 

I don't use it but there are a bunch of guys on here who swear by it. I have never heard one negative about it either. The RL SPH is pretty thick. So try the spectro and see what happens. I use the RLSPH but right now have some BelRay 85w140 in there from the dealer. Runs fine.

 

I used it once in my 6-speed as it was advertised to reduce gear whine. Didn't notice any reduction in 5th gear whine over the RLSPH it replaced, so when change time rolled around I went back to Shockproof as it was $5/qt cheaper than the Spectro Platinum. Wear, as determined by metal particles on the mag plug, was comparable to Shockproof, i.e. practically nil.
It's a good oil & should work well in your 5-speed.

 

I'm not sure, but I thought the 5-speeds need to use motor oil rated GL1 and the 6-speeds use gear oil rated GL5.
I thought I read this somewhere.
I would check on this if I were you.
I use spectro HD 6-speed. It was formulated specifically for the 6-speed.

 

I'm pretty sure the 6-speed is rated for GL-1 as well, which is why HD allowed Syn3 to be used in it. The recommended tranny oil (Formula+) is GL-3, per an Amsoil VOA I saw awhile back.

The HD tranny is a fairly benign environment, 5 or 6-speed, and doesn't require much in the way of specialty oils. I know several long-distance riders running plain old $3/qt gear oil in their trannies that have over 100k on their bikes with nary a problem...

 

Heavy Duty Platinum 6-speed Transmission Oil
Designed by Spectro in response to complaints from Harley owners about the great but noisy new 6-speed transmission, this full synthetic provides ultimate lubrication protection. Formulated to significantly reduce gear noise and provide easier, smoother shifting, this SAE 75w140 formulation eases shifting even when cold. High loads and extreme heat do not affect the oil, so it performs well when pushed hard and long. A.P.I. GL-5 rated 75w140

 

I tried Bel-Ray 80-140 Hypoid GL, once a couple yrs ago, dealers where saying it helped the 5th gear whine which I didn't really have, I had to listen for it to hear any.

Problem I had was on cold mornings it shifted really stiff for the first 10 mins or so after starting.

That Bel-Ray GL is not a SYN oil so I dropped it after about 1500 miles and put in some MOBIL 1, 75-90 GL and really like it. Been using it for the last 20K.

 

What about another brand besides Spectro? Is Amsoil 75-140 ever tried and did it resolve the noise?

I, too, have a very noisy, clattering 5th gear in my '08 Heritage. I did a total oil change on my bike last year and I used the Amsoil Synthetic 75W-140 gear oil in the 6-speed tranny. I used it only because it was a synthetic and I was in the shop that had it so I bought it. This all occurred before I discovered that the 5th gear in my tranny was very noisy.

I now only discovered just how bad my tranny is even with the Amsoil oil in it. It isn't a gear whine noise, it is a real chatter, clatter noise. Now that I have been reading about everyone's issue with the noise I wonder if the Amsoil is as good as or equal to the Spectro. I suppose that I am just about due for another oil change and I don't want to change out the tranny oil only to discover no difference between the two brands.

 

been using it for about 5 years and over 100K in my bikes it works
But so do all the others.
I use it because HD dealer sells it at a fair price