I've been using Redline Heavy Shockproof in my last two Harleys and am sold on this stuff. My new '09 with its 6 speed tranny seems to like it too with typical 5th gear whine really reduced.

I've been reading a bit about Spectro's new 6-speed lube and wonder if it offers any benefits over Redline. I know its viscosity is less than the Redline Shockproof, but other than that I know nothing else. Anyone care to offer experiences with the two lubes? Inquiring minds would like to know.

 

Both are good but the RLSPH is about as heavy as you will find at 75w250.

 

I wonder the same thing, I have an FXDLI , reg hd in tranny, wanna change to syn, best would be redline ?? easire to get for me, I tried to look for spectro's 6 sp oil, no availablity tho

 

I used the Spectro in my 08 Street Bob at my first service. I just swithced last week to Mobil1 75/90, I am happier with the Mobil -- easier shifting, quiter shifting, and when I changed the fluids out, there was some noticeable residue on the drain plug.

 

I run the Redline and I'm very happy with it. In the new 6 speed tranny's you should run a GL-5 gear lube for optimal performance. I have not tried the spectro 6 speed but I'm also considering it. If I do I will let you know what I think.