Oil Spec
 

2005 FLHTCI
What oil for tranny and primary?I have 10w40 Mobil 1 Racing 4t for the primary and Mobil 1 75w-90 synthetic for the tranny?Will this work? Or what do I need?Thanks Harry

What you have will work just fine.

Yes both will work fine.

To keep it simple, you can use Formula+ Transmission and Primary Chain case lubricant in both.

Or use Mobil 1 V-Twin 20w50 Syn in all three holes.
It's made for it.
Simple, I have been using it for years.
https://mobiloil.com/en/motor-oils/m...QNWg&gclsrc=ds

Thanks,Harry

Harley recently came out with an 80W-140 lube for transmission and primary. I saw nothing on the label indicating it won't "retro-fit" into older bikes. I mention this primarily to bring up the question about why people use 70W-90 in the transmission when 75W-140 flows about as well cold and retains its viscosity better at high temperature. A caution about gear oil in the primary (not Harley's lube), the extreme pressure additives can have a bad effect on "yellow" metal (a big reason for not using it in engines) and I am not certain if the copper windings in the stator qualify as "yellow" metal.

Did your bike not have an owner's manual included? Unless you live where it is regularly quite cold, Harley recommends 20W-50 for the engine, but 10W-40 for low temperature operation. Many OWNERS have long preferred purpose made lube for each hole, engine oil in the engine, gear oil in the transmission, and primary lube in the primary. Harley is slowly coming around to agree with the owners and no longer pushing the same lube in all three holes. If you have a manual, read it. When asking for advice, you generally get "what you pay for". Everybody has their own opinion.

Harry.....keep the change.

Harry... Think man think. You put your physical address as your location. All you did was advertise on the internet where your 2005 FLHTCI is located. Every thief in the world thanks you.

It took me less than 10 seconds to find out your last name starts with a J and ends with an S and you live in R***land, SC. Now, if you are looking to give your bike away that's a different story.

I would send you a PM about this but you don't have enough posts.

Seriously....what ever oil you have handy to dump in the primary....it isn't going to matter. And ANY gear oil in the trans is going to work as well. Don't over think this...it is an antiquated v twin motorcycle engine. Change the oils and ride for Christ sake.:icon_moped:

I used Amsoil 75-110 in my 5 speed when I had it. Well over 90k and that’s what is still in it.