Gearbox Oil

[sam12]

i have read somewhere not to use synthetic gearbox oil,i am currently using synthetic is this doing any damage /do i need to change.

thanks,sam

[baldilocks]

I think it depends who you ask !

I'm not trying to be funny, some dealers use synthetic, there is info on the Gas Gas USA website advising people NOT to use synthetic as it reacts badly with the clutch plate material and to use Dexron 3 ATF. I noticed last week that Trial and Enduro Direct are now selling Motul ATF which they recommend.

When I next change oil I'll try ATF, my 09 looks like it has synthetic motul in and to be fair its been fine so far.

Edited December 2, 2008 by Baldilocks

[peterb]

Hi sam and Baldilocks,

Jaan had the same question on the site a while back that I forgot to respond to. It has been said that Al the Spanner has advised that a synthetic oil is ok in the PRO gearbox, I have a lot of faith in Al and trust his judgement, he has worked on GG longer than I have and is a superb mechanic, a good lad too. I also trust the report on the GG USA site. I always use a mineral oil in the PRO (and previously in my older GG motors) gearbox, 10 weight, hard to find though, so I recommend the ATF rated to Dexron III as an alternative.

When the first model PRO's eventuated, there were problems with the clutch fibres swelling (amongst one or two other things), now this would not matter to any other type of clutch except in the case of the pro, it has a diaphragm type spring and lever arrangement to compress the plates together, in lieu of conventional springs and any swelling of the fibres seriously affects the release action of the clutch - by altering the mechanical advantage of the levers. It was found that synthetic oils caused the plates to swell and that was why mineral oil was recommended. This is not to say that only GG plates swell with various oils, other manufacturer's may also do this but because of their coil spring arrangement, the action is not affected by any noticable amount.

Since 2002, GG have had many clutch plate material revisions, it may be that now there is no longer any problem with synthetic oils in the later PRO gearboxes, though I have not heard of any recommendation to say so.

I have worked on and ridden GG for the last 16 years and have always used mineral 10 weight in the gearboxes, without any problem, I am a bit old fashioned in some respects, and like using stuff that works well if you know what I mean. I still run 50:1 for the fuel/oil. Anyway, it works well for me. The first fill fluid for all the PRO's is from GRO, I can not say if it is a mineral in the gearbox for definate. Hope this helps.

Bye, PeterB.

[beatabeta]

Was always advised to use Dexron III ATF which I did and never had any problems. Know most of the top GG riders also use this.

[sam12]

i am using putoline gp10 synthetic sae 75w gearbox oil,is this suitable?

[peterb]

Hi sam12,

I would say no.

Bye, PeterB.

[jse]

Hi sam and Baldilocks,

Jaan had the same question on the site a while back that I forgot to respond to. It has been said that Al the Spanner has advised that a synthetic oil is ok in the PRO gearbox, I have a lot of faith in Al and trust his judgement, he has worked on GG longer than I have and is a superb mechanic, a good lad too. I also trust the report on the GG USA site. I always use a mineral oil in the PRO (and previously in my older GG motors) gearbox, 10 weight, hard to find though, so I recommend the ATF rated to Dexron III as an alternative.

When the first model PRO's eventuated, there were problems with the clutch fibres swelling (amongst one or two other things), now this would not matter to any other type of clutch except in the case of the pro, it has a diaphragm type spring and lever arrangement to compress the plates together, in lieu of conventional springs and any swelling of the fibres seriously affects the release action of the clutch - by altering the mechanical advantage of the levers. It was found that synthetic oils caused the plates to swell and that was why mineral oil was recommended. This is not to say that only GG plates swell with various oils, other manufacturer's may also do this but because of their coil spring arrangement, the action is not affected by any noticable amount.

Since 2002, GG have had many clutch plate material revisions, it may be that now there is no longer any problem with synthetic oils in the later PRO gearboxes, though I have not heard of any recommendation to say so.

I have worked on and ridden GG for the last 16 years and have always used mineral 10 weight in the gearboxes, without any problem, I am a bit old fashioned in some respects, and like using stuff that works well if you know what I mean. I still run 50:1 for the fuel/oil. Anyway, it works well for me. The first fill fluid for all the PRO's is from GRO, I can not say if it is a mineral in the gearbox for definate. Hope this helps.

Bye, PeterB.

Peter,

I have an 02' 280 Pro with a later clutch pack in it and have been using the GM AutoTrak II for several years now with no fiber plate swelling (the stock 02' fibers tended to swell). I understand the GM transfer case fluid is a synthetic but has been no problem as far as my experience is. I've found that the Ford Type-F ATF works well in the late model clutch packs with the lighter springs, but a lot of riders use the Dexron II ATF with no problems over here.

Perhaps the reason my clutch lasts is that I usually try to change the fluid every 5-12 hours of use and run a magnetic drain plug top and bottom. I read in one of the GG owner's manuals they recommend trans oil change every 60 hours, which seems way off the chart for a competition engine and I was sure it was a misprint.

Jon

[thumperbob2002]

I bike shop near me has recommended Rock OIL Gear Oil 10W/30 , a semi synthetic oil for two stroke gearboxes- I havent used it yet- would you say this is suitable for my `02 pro?

Cheers

Bob

[jse]

I bike shop near me has recommended Rock OIL Gear Oil 10W/30 , a semi synthetic oil for two stroke gearboxes- I havent used it yet- would you say this is suitable for my `02 pro?

Cheers

Bob

When I lived on the West Coast, I used Rock Oil products a lot in my Trials bikes (and the Pro MX bikes I built) with very good results, but I get a blank stare from the parts guys at the shops here in the Midwest when I ask about it. Since it's designed for bikes and will have the appropriate additives and modifiers for a wet clutch environment, I'd say give it a try and see how you like it. The main thing is to change it often to keep it fresh and clean, which in the long run, may even be more important than what type of oil you run, especially in the crank bearing and internal bearing transmission split-shaft-lubed, small capacity Pro transmissions. Your 02' only takes about 350cc's and it has to lube a lot more parts and dissipate extra heat than any other two-stroke Trials tranny.

Jon