ATF vs Gear Oil ( Form motorcycles)

[desmond197]

I have been doing some reasearch with my fellow Mechanical Engineers on the use of AFT in manual transmissions. With the low stress and realativly low power output of our vintage bikes I have concluded ATF is the way to go. The trick is change it a couple of times a year and you should be good. The wear factor for the temperature and loads we are running in our transmissions is the same for ATF as it is for synthetic gear oil. For years I ran Mobil 1 motorcycle fourmula in my gear boxes but at $10.00 a quart it gets a little expensive.

I have found that Ford and Mercedes use ATF in thier racing cars manual transmissions. Puch recomends ATF in the Puch 125 and 175's back in the day and they were right.

Nevery use regular motor oil in your gear box. The additives will destroy your clutch.

[G Ellis]

desmond197.. I have use ATF in all of my Pentons for years, 1400cc on all of my bikes. I change it every two races. On my GS6 if I run in a CC where there is alot of water,I change it every race. I byu mine by the 5 gal from Walmart. Later Gary

[John Ehrhart]

That's all I've ever used in the KTM motors. Less clutch drag and it helps you find those small cracks when you've bashed a rock!

1969 Husqvarna 400 Cross
1974 Monark
1975 Jackpiner
1978 GS6 400
1981 250 MX

[john durrill]

ATF is what Lorain recommended back in 72 for the gear box. It helped a lot with clutchs at checks in enduros. The checker didnt have to run beside you to write on your card . chuckle chuckle
John D.

[Speedy]

quote:Originally posted by desmond197

I have been doing some reasearch with my fellow Mechanical Engineers on the use of AFT in manual transmissions. With the low stress and realativly low power output of our vintage bikes I have concluded ATF is the way to go. The trick is change it a couple of times a year and you should be good. The wear factor for the temperature and loads we are running in our transmissions is the same for ATF as it is for synthetic gear oil. For years I ran Mobil 1 motorcycle fourmula in my gear boxes but at $10.00 a quart it gets a little expensive.

I have found that Ford and Mercedes use ATF in thier racing cars manual transmissions. Puch recomends ATF in the Puch 125 and 175's back in the day and they were right.

Nevery use regular motor oil in your gear box. The additives will destroy your clutch.

We have used ATF in all Zuendapp trannys (and forks)since day one.
But OPTI 30 in our SACHS 7A engine.
Speedy------->>>>>>>>>>

Helmut Clasen KTM
162 Hillcrest Ave
L9H 4Y3
Dundas Ontario Canada
Ph.905-627-5349
[email protected]
http://speedy_c.tripod.com
Sachs GP-GS 250-7A reeds
Hercules 350-7A
Hercules 250-7A
Zuendapp 125 GS
KTM 200 EXC 2003
KTM DUKE 96 Spec.
KTM Adventure 02

[Lew Mayer]

I also used to run ATF but the question I have is what is the best type to run? Back in the day, I was told to use Type F. Any thoughts on what type of ATF is best for trannies and clutches. Dexron? I?,II?,Type F?,Mercon? (Now my head hurts.)[)]

Lew Mayer

[G Ellis]

Lew I received the backing plates today. I use Dextron III with good luck. On the cost to fix the backing plates, just an arm and leg. If I can get out to my shop, we received 6 in of snow tonight. I will have to put the bikes on hold and get the snowmoblie out and have some fun.[][][] Later Gary

[Dwight Rudder]

quote:Originally posted by desmond197

I have been doing some reasearch with my fellow Mechanical Engineers on the use of AFT in manual transmissions. With the low stress and realativly low power output of our vintage bikes I have concluded ATF is the way to go. The trick is change it a couple of times a year and you should be good. The wear factor for the temperature and loads we are running in our transmissions is the same for ATF as it is for synthetic gear oil. For years I ran Mobil 1 motorcycle fourmula in my gear boxes but at $10.00 a quart it gets a little expensive.

I have found that Ford and Mercedes use ATF in thier racing cars manual transmissions. Puch recomends ATF in the Puch 125 and 175's back in the day and they were right.

Nevery use regular motor oil in your gear box. The additives will destroy your clutch.

I agree fully with never using automtive oils in your motorcycle.
But what is your background in saying that ATF is what you and your friends recommend.  What sort of testing have you done ?  
Why would you say that ATF is better than specifically designed gear oil for motorcycles ?  I know some bikes like the Zündapp has to have ATF or it won't shift right but what about other transmissions that were designed for gear lube. ?  I know it will work but is it the best for transmission longivity ?  ATF like automotive oils have changed formulation over the past 30 + years.
Why do you say that our vintage bikes transmissions are lightly stressed ?  If they were then nobody would ever break gears or other transmission components.  And we have destroyed our share of gears over the years.  Even vintage bikes put out more Horsepower per CC than any auto engines.  If a Good running Sachs 125 put out 21hp, that would mean that a 2500cc auto engine would put out 420 hp.   I doubt it.  They rebuild racing transmissions on factory race cars as much as they rebuild the engines.  So that isn't a good comparison.
So, I just want to know how you came to this conclusion.
Cher'o,
Dwight Rudder
7 time ISDT / E medalist
8 time National Enduro Class Champion.

[OUCWBOY]

Dwight,
Back in my street drag racing days, in the era of the pony cars, I would have sold my soul at that rate, my 427 would have be running 1176 HP WOW. Very good way to make your point. Good Job

Donny Smith

[desmond197]

Dwight I have a BSME and I was talking to some SAE certified lube engineers about this question. One of the guys gave me this thread on one of the engineering forums.

//www.eng-tips.com/viewthread.cfm?qid=5862&page=3

What interested me were the results of the 4 ball wear test.

It is true that the vintage bikes do put out a lot of HP per liter but they are not as stressed as a modern racecar mainly due to the higher temperatures.

I must say that I am impressed by the design and manufacture of the gears in a Sachs motor. They were desinged for a lot more power then they generaly have to deal with. Do a hardness test on them some time they are about as hard as you can get with out being brittle. I wished they had designed a better selector mechanism.[}:)]

[Dwight Rudder]

Part of the problem with SAE standard is that it doesn't take into account motorcycle wet clutches. Thankfully now the JASO standard has a MA and MB motorcycle rating.  The MA is for wet Clutch motorcycles and the MB is for Motorcycles with separate engine and transmission lubrication.  

Here is a reply from one of your friends on this thread :

romke (Automotive)     
17 Apr 01 14:46
the load carrying capacity of an ATF will no doubt be lower then with a conventional gear oil (with usually a higher viscosity). However, in most gearboxes, load carrying capacity is not of prime importance and hence ATF's can be used quite well with usually a better cold shift performance. In the long run wear may be somewhat higher, but there are automakers who have employed ATF in manually shifted gearboxes for years (Mercedes-Benz!). For racing applications the outstanding thermal stability and antioxidative properties of an ATF may also be very welcome, together with the improved shift "feel" and, due to the lower viscosity again, sligthly lesser powerloss in the geartrain...and of course - gearbox life in racing is counted in hundreds of kilometers and not in 100000's of km.

This alls add up to a very useful alternative to conventional gear oil. If an ATF is really too thin, a 5W-30 engine oil or a modern synthetic SAE 75W-80W gearbox oil might give the extra load carrying capacity you need.

==================================================

What I gather from that thread is that you can use a ATF but it isn't the best to use in the long run.

I will continue to run ATF in my Zündapp because that is what is required for it to shift properly, but for other applications I will use Motorcycle light gear oil. 75w or 80W.  Similar to 30Wt SAE. in viscocity.  
Thanks,
Dwight

Dwight Rudder
7 time ISDT / E medalist
8 time National Enduro Class Champion.