Can I run a gear lube in my sportsters primary/transmission box? The manual says to use HD primary drive lube but I would prefer a GL5 for the gears. What do you guys/gals run?

 

I'm running as of now Mobil 1 75-90 syn gear oil.

 

How many miles have you been using M1 75w-90 in the chainbox/tranny? Clutch still works OK?

 

Same here Mobil 1 75-90 syn gear oil. It's spproved for the trans/primary. Gear shifts are quieter since I changerd from 20w-50.

 

Who approved it for the trans/primary? My fear is around the wet clutch. How many miles have you been using it?

 

The Mobile 1 syn 75w-90 bottle reads "Exceeds requirements for API GL-5". What is it don't you understand? I've only been using it for 6000 miles. I installed it at the 1000 mile change. If you read some of the prior posts here regarding oil, there are peeps here that have been using it much longer.

 

I know the big twins use gear lube in the tranny but they don't use gear lube in the primary. What I don't understand is if gear lube is OK for the sportster's combo primary/tranny box. Many gear lubes have high concentrations of antifriction additives like Moly or Boron which can cause slip in the clutch (leading to premature clutch wearout). Some clutch materials don't care (like those found in eaton type differentials) and some do.

My owners manual only says to use HD formula+ primary and transmission lube. I'm glad you're having success with Mobil 1 75w-90...that gives me hope.

 

Sportrans Harley fluid . Never had a problem...Mark...

 

An alternative might be to go to Red Line Oil's site.

 

There are dozens of previous posts on this forum about oils. Mobile 1 GL-5 works great in the sporty primary/trans. If you want to run Citgo oil then by all means buy HD brand oil. If you really want to read up on the subject I suggest tryingthe Search button at the top of the page and query oil, synthetic, oil primary, etc. I don't at all mean to sound rude, but there is tons of information already here if you search for it.