rb0804 Posted March 8, 2010 Report Share Posted March 8, 2010 I am confused the last time i overhauled and automatic transmission i seen alot of gears in them. A motor oil is not meant for wet clutches, and the last time i overhauled a car engine i didn't see many gears in there just timing gears with a chain. ATF is however designed for wet clutches since there are on the average 4 clutch packs in an automatic and 3 sets of planetary gears. ATF is more of a hydraulic oil. Automatics also have pumps and oil passages that apply 'pressure' to the drums to eliminate slippage. A lot of the aftermarket shift kits up the working pressure of the transmission, making it harder for the clutch pack to slip. As far as the bike goes I use SAE 30. Quote Link to comment Share on other sites More sharing options...
firebanshee Posted March 8, 2010 Report Share Posted March 8, 2010 (edited) ATF is more of a hydraulic oil. Automatics also have pumps and oil passages that apply 'pressure' to the drums to eliminate slippage. A lot of the aftermarket shift kits up the working pressure of the transmission, making it harder for the clutch pack to slip. As far as the bike goes I use SAE 30. ATF has friction modifiers in it to help the clutches grab. Type F and B&M trick shift are the most aggressive types of atf. I am painfully aware how an automatic trans works, i have been working on them and overhauling them for over 20 years. Edited March 8, 2010 by firebanshee Quote Link to comment Share on other sites More sharing options...
sketch2 Posted March 8, 2010 Author Report Share Posted March 8, 2010 Alright thanks guys for all the good feedback and info, helped out alot Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted March 8, 2010 Report Share Posted March 8, 2010 ATF is more of a hydraulic oil. Automatics also have pumps and oil passages that apply 'pressure' to the drums to eliminate slippage. A lot of the aftermarket shift kits up the working pressure of the transmission, making it harder for the clutch pack to slip. As far as the bike goes I use SAE 30. Yea but most light duity manual transmissions in cars and pickups specify ATF. No oil pump, no clutches just gears to lubercate. There is no way I would run a SAE 30 weight oil. That isnt even recomend for most engines (other than small yard equipment) built after the 50's or 60's. Just use a oil that is SPECIFICALLY designed for a 2 stroke tranmission. You can put just about any kind of oil in the transmission and it wont lock up. Quote Link to comment Share on other sites More sharing options...
rb0804 Posted March 8, 2010 Report Share Posted March 8, 2010 The thicker the oil, the more HP your are going to be losing to parasitic drag. Quote Link to comment Share on other sites More sharing options...
klever209 Posted March 8, 2010 Report Share Posted March 8, 2010 I ran a 10w30 motor oil once because it was all I had on hand after a clutch swap. BIG MISTAKE! The thing was slippin so bad I drained it out, put 10w30 motul tranny fluid. Ended up flushing the thing about three times and re-adjusting the pancake bearing to get it going right. Never will I use anything but a TWO STROKE transmission fluid/oil. Just not worth the headaches. It is a bit pricier though, but I only ride about six to eight times weekends per year. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted March 9, 2010 Report Share Posted March 9, 2010 I ran a 10w30 motor oil once because it was all I had on hand after a clutch swap. BIG MISTAKE! That is what happens when you use an oil designed for car engines. You can run yamalube 10w30. If you run engine oil then you need to make sure it is wet clutch compatable. You get better shifting with an oil that is made for a 2 stroke transmission though. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted March 9, 2010 Report Share Posted March 9, 2010 The thicker the oil, the more HP your are going to be losing to parasitic drag. That is true but the Bel Ray Gear Saver 75w, 80w, and 85w's have an engine oil viscosity from 10w30 to 10w40. Some time shake a quart of Gear Save 75w then shake a quart of 10w30. The gear saver isnt thick like the weight numbers emply. ATF is thiner but it gets dirty faster. Quote Link to comment Share on other sites More sharing options...
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