does anyone? or can you run atf in the primary?? someone told me it was good to run in there,, any sugestions?

 

barnett and alto both recommend it for their clutches, its supposed to be better for the clutch friction. Some people think it isnt good for the rest of the primary, but thats bs. It works just fine to lube the chain and keep the stator cool. I've been running it in my bikes from the get go with no problems. ATF-type F is usually what i run in the stock clutch, $5 advance auto brand, works great. I run B&M trick shift on my 1990 with the Barnett extra plate clutch. Hooks really hard.

 

I do. Some like the idea, others don't. Some clutch manufacturers recommend it. Other riders will say its not thick enough for the primary chain but its been doing just fine in automotive transfer cases for years. Also works fine for heavy equipment drive chains.

 

I ran it for a while. I was worried that it didnt contain enough lubricating properties. Switched over to mobil 1 0w20.....steve

 

Do a google search for the major brand atf and read what they say. They are pretty negative on it. Lots of people think since the clutch looks similar to an auto transmission it is OK but a auto transmission clutch has tremendous hydraulic pressure drive it and the fluid is pressure driven for lubrication unlike the washing machine lubed primary. Probably good enough for the roller chain and the clutch is fine with it but the large inner primary pin bearing and the large clutch hub ball bearing need a little heaver oil. Just my opinion. Probably 90% of Harley don't get enough use to matter. If you really put the miles on, drive it in hot weather and such, I would get off the 5 bucks and use a quart of Harley straight weight formula + . There is one brass type sleeve bearing so stay away from the grade 5 hypoid in it and the transmission. Sorry to make this another typical oil thread to be. Remember to do the level, not amount.

 

Here is a good write up on the subject. I "did not" write the article. Stole it after doing research.

First of all I want to state that I'm no engineer and the observations here are from personal experience and 40+ years as a auto and bike repair shop owner/mechanic. In the last 30 years I've built well over 1000 automatics for every application from stock to all out race applications in 1000+hp race cars and monster trucks.

For those of you (including myself) that use ATF in the primary here's some facts that I have verified over the years.
There are approximately 25 types of ATF but I'll cover the 5 most common as the other twenty are either obsolete or very vehicle specific.

Type F or (Ford) fluid was developed for and used in Ford automatic transmissions back when the clutch discs were made of sintered bronze or asbestos and there were no bearings used. All parts were supported by bronze bushings and thrust washers. It is essentially 20wt hydraulic oil (pure mineral oil) with a red dye and that's it. It is commonly sold as Racing ATF under brands such as B&M Trick Shift because it provides the quickest lockup of the clutch packs (Hardest shift). It has no place in 99.9 percent of modern applications unless you're just looking for neck snapping shifts (or in the case of motorcycles used for drag racing where quick and harsh clutch engagement is the primary goal and you're gonna change it very often.

Dexron II and III are the most commonly used fluids with the only difference being additives in Dexron III to make it more compatible with the electronics used in modern transmissions.
They both have an additive package that includes friction modifiers for smoother cluch engagement, oxidation control, viscosity stabilizers, corrosion inhibitors and proper lubrication of bearings and bushings of all types. Since the advent of gerotor pumps and better friction materials such as Kevlar and Aramid, Dexron II or III has even replaced the use of Type F for racing use by most transmission builders.
Dexron III is commonly used in many automotive manual tranmissions and is probably used in more transfer cases of 4WD vehicles than any other fluid.

ATF+3 uses higher quality base oils with the highest content of friction modifiers to prevent torque converter shudder. It lubricates a bit better than Dexron III but can also cause slow clutch engagment (slipping). If you ride easy and your primary goal is smooth clutch engagment then this is the fluid to use in your primary if you're gonna run ATF.

Synthetic ATF comes in many formulations but the most common is Dexron III. It has the same properties of clutch engagement as Dexron III with some advantages.
The main advantage of synthetic fluid is it's ability to resist thermal breakdown. If you ride in extreme heat or just want to extend your primary fluid change intervals then this is probably your fluid.

You may want to think about this too. Although the primary doesn't generate much heat in and of itself that's not the only concern when choosing a fluid.
The primary on your motorcycle is not a seperate entity. It is attached to the engine and it acts as a giant heatsink for that engine. The temps seen on a long hard run are probably within 20-40 degress of the engine oil temp.
Mineral based ATF starts to break down at around 220 degrees and is almost useless as a lubricant at 250 degrees.
On most Harley's the rear exhaust is in close proximity to the primary case and that adds heat too.

I have measured the temp on my primary after a hard run and have never seen temps above 180 degrees but that doesn't mean it doesn't happen. If you ride loaded, two up, in heavy traffic, the desert, or alot of hard pulls in the mountains then you'll probably see temps over 200 degrees.

Most people notice that shifting is immediately improved when they change over to ATF in the primary. This is because ATF is designed for wet clutches. When you pull the clutch in it releases cleaner than with motor oil. You'll also notice that finding neutral is no longer a chore.

Personally I use any major brand of regular Dexron III and change it out every 5000 miles but if I did alot of the riding described above I would probably use synthetic (although I am a cheap old bastard).

I'm not promoting the use of ATF in the primary!
But!
ATF has proven itself in hundreds of millions of auto applications and tens of millions of manual tranmissions and transfer cases.
You almost never see a 4wd transfer case failure anymore and I've personally seen 4wd trucks with a quarter million miles on a manual transmission and transfer case using Dexron III and still going strong.

I feel comfortable using it in my primary and I love not hearing the rattle when I snick it into first. But what I really love is not fussing with trying to find neutral on a cold day. And the over 300,000 miles I've put on primary's with ATF without a single lube related failure doesn't hurt either.

 

wen my spring plate blew I bought a barnett set of plates (friction and steels)

it said atf. so thats what im using. Im happy

 

I ran it for a very short while because of how loud it made my primary noise.....didnt like the racket.

 

I tried ATF and found it ok, better than oil. But in the back of my mind, had reservations. Switched to Mobil diesel syn 5W40 and found that the performance pros of ATF (easy shift, easy neutral, no bounce skiping during shifting, etc) was also apparent with the syn 5W40. so I use mobil diesel syn 5W40. Use what ever you like. I do agree that thinner oils and/or atf cools or heats the stator better.

 

good post perki! Your description of ATF F and B&M matches what I thought. I'm willing to change more often to get the serious hookup that suits my riding style. Temps havent been an issue for me, 2-1 exhaust thats awy from the primary probably helps some. I've probably only got 75,000mi or so since I started using ATF, but I've yet to have anything in the primary(s) fail yet. As long as your aware of the type of fluid you're running, and it's advantages and limitations you'll be good. There's no unicorn blood in Harley fluids that makes them the only thug you can use...