TRANNY LUBE ?

[arty]

I have been using syn 75-90 gear oil in the gearbox on my 2004 Heritage for a few years.  I am wondering if I should go back to syn 20w-50w syn twin motor oil.  I have no problems with either but I would like to hear the consensus out there on the subject. 

[L-]

Try some Redline Shockproof Heavy.  Put 18-20 0z's in there.

[Caper]

Use your 20w-50 for the engine and stick with gear oil in the tranny.

[dakota224]

What he said..  20W50 in motor only

[arty]

I was doing the spring changes - engine-primary & tranny and somehow I must have dumped way to much gear oil in the gear box.  It was leaking out through the output bearing shaft from the tranny to the primary.  I took out about 4 ounces and it stooped the leak.  I thought that I might need a new inner primary seal which was not a fun thought right now.

[HDSlowride]

I used Heavy Shockproof for years but I changed last winter to Mobil 1 75W-140 SUV gear oil. I ride all year long and that Shockproof is some thick stuff. If I only rode in the summer, that's all I would use.

[Sonny S.]

Amsoil 75/110
tried 75/90 & 75/140 in multiple brands.
75/110 seems to work real well year round

[harleyjt]

I recently tried some Redline shockproof in my 08 Ultra when I did the 10k.  I have been using BelRay 85-140 Hypoid gear oil (same as their VTwin trans fluid) for the last 10 or 12 years in each of my other bikes.  At the next service interval, I'm going back to the BelRay. I think it shifts smoother than the Redline, and gives me quieter (5th gear noise) operation than the Redline. 
jt

[1JITSU1]

Also AMSOIL 75-90

[Ultrashovel]

Belray 85-140 is excellent for shifting. I prefer a gear oil. 20-50 is not good enough for a tranny, IMHO.

[Phu Cat]

Tranny lube has different requirements than engine lube.  That tell ya anything? 

PC

[Milehog]

Gear boxes like additives such as sulpher that would kill a gas engine. Typically multi purpose engine-gear oils only have a GL-1 (gear oil) rating. Treat the tranny to real gear oil (GL-4,5), save the real engine oil for the engine.

[Hawg Holler]

So many people equate heavy with good. But heavy oil especially in cold temperatures does a very poor job of lubrication until it gets really hot. Just because it's used in racing, which is a specialized application, doesn't make it good for everyday operation. Unscrupulous used car dealers used to pack rear ends and trannies with really heavy oil or even sawdust to quieten them down until they could get a sucker to drive them off the lot. STP is nothing but an oil thickener that gums up the lifters and other parts to keep them from rattling around, but it doesn't lubricate better.

Oh no, I got involved in an oil discussion. Forget  I said anything. Whatever you use is exactly the right lube. Everybody else, including the Moco, is wrong.