Well i thought i would go with the ATF type F in the tranny of my bikes. i did this for close to a year on my 95YZ125 and i think my 82RM250 restore has been finished for about 3-5 months.. first off it has to be changed every 2 hours or when the clutch slip starts to bug you......yz125==loose clutch basket gear rivits, badly grooved basket and boss. clutch just totally smoked... rm250==blew out 4th gear totally and 2 shattered clutch disks.... you can take this info how you like. no i don't want to argue about it.... and NO this was not the perfect controlled experiment.... but i',m never running ATF again:ride:

I wouldn't think loose rivets and grooved basket would have anything to do with the type of fluid. Those two items are load/stress related. Me personally I have had no problems with ATF, but I'm like you and don't want to get in a cage match over it. Everbody do what's been working for you.


P.S. Wow you have a lot of schratnell to clean up.

None of the problems you describe are lubrication issues, so there's nothing to argue about. The real test would be to look at the wear surfaces while the trannies are apart. How do the faces of the gear teeth look? The dogs? The shafts?

guess you realize the automatic trans in your car or truck runs wet style clutches and gears in them too don't you ?
and those have been around a while now too ..........................
so i'm thinking it something besides the fluids too .

I personally would not have imagined that using ATF would have caused this level of damage. Although I personally do not think that the cost savings is good enough to consider using ATF.

Lets just say that you are going to change your oil about 10 times this year. If you use 1 quart on average each change, and ATF is $3 per (I think that it's about that... ?) and my Golden Spectro is at $8.50 per. This means that over the course of a year, you will save $55. But for the piece of mind and knowing that not only does my bike shift great, and the clutch is smooth with Spectro ~ I do not think that it's worth giving that up for the savings.

Please guys, I know that this can be a heated subject, with an equal amount of passion on both sides. So let's keep the bad gas out of this.

And let's not forget that my 2 stroke does not have a oil pump, a filter, and a cooler ~ like just about every auto transmission (car or truck).

ya like i said it wasn't a very controlled experiment. but once i got away from the ATF and just ran regular 20w50 4 stroke motorcycle oil i think the oil feels better and lasts longer. the shattered clutch plates on the 250 are not fluid related(had to file the grooves out of the basket) but i wanted to blame it on the ATF:) as far as the rivits and grooves, i don't know i've seen plenty of clutches and i've never seen one that bad. in my opinion the blame is on the ATF. and the blown 4th gear i'm blaming on the ATF also. i rebuilt that motor and 4th looked just fine while i had it apart. i'm starting to think ATF has NO impact cushion and thats why the grooves got really bad and 4th gear went.

ya i think impact cushioning or lack their of is the issue. as far as car trannies its already been disscused and explained that all parts in a car tranny have tighter tollerances therefore have very little accual impact of parts.. i'm still blaming the ATF.. i didn't want to debate but did want to make the point about impact cushioning and not being able to completely dismiss my problems as not fluid related

zig06 said:

I don't use ATF to save money, I use it because I like the way the shifting and the clutch feel with ATF.

And after more than twenty years of using ATF with no unusual wear and zero tranny failures, I just refuse to believe the ATF had any contribution to the OPs failures.

atf is a high grade form of hydraulic oil.i don't think it has the same viscosity as say golden spectro

earthmx said:

ATF is approximately equivelent to 25W engine oil.

Chokey said:

if you read the spec part of the hydraulic oil as compared to the atf there are quite a few similarities.

hydraulic oil comes in a 20wt as well.aw 48 would be equilvilent to a 10wt while an aw68 would be a 20wt.

Chokey said:

I agree. Those failures are not related to ATF. Believe what you want, but it is more than likely that you would have had those same failures no matter what you were running in your trans.

earthmx said:

its basically just a better more expensive hydraulic oil , some people run it for hydraulic oil in machinery . most don't because its just cheaper to get hyd oil .

i always throw a liter the hydraulics to die it red so you can actually see it in the dam sight glass .

Have you given any consideration to the fact that the bikes you are talking about having issues are 14 and 27 years old?

jeffgg said:

and now were on to something lol:lol:

Been using Type-F for about 5 years, all good.

jeffgg said:

lol finally someone said it.

i used to run gear oil in a TRX250R i used to own, i smoked 3rd gear and all clutch components. my conclusion: it was a 25 year old quad, not the wrong oil.

I'm going to agree with the others in that the failures were not caused by lubrication issues.

I like that argument that car transmissions have tighter tolerances than dirt bike transmissions. I've read that quite a few times on here, but would love to see numbers to back that up. Something like a backlash spec for gears, or just anything that can quantified and compared between the two.

Also, there are loads of cars out there that use ATF in manual transmissions and transfercases, straight from the factory. There goes the theory it won't work in high-shear applications. And we all know (or should know) that ATF is designed to work with wet clutches (bands). All in all it's a pretty ideal oil for motorcycle transmissions.

I've been using Type F ATF for years in all of my bikes. Why? Not because of the price, but because I like the way the clutch works and the way the bike shifts. Less clutch drag too (especially in the colder temps we see here).

I've never seen any significant wear or had any problems. Change it at a regular interval and you will be fine.

ATF works fine in my 11 year old bike.