slingblade Posted May 21, 2015 Share Posted May 21, 2015 going to change out the gear oils soon and wanted to hear some feedback,ive got the 13 speed road ranger and live in Ga and was going to use 89w / 90 EP Quote Link to comment https://www.bigmacktrucks.com/topic/40110-has-anyone-used-the-mystic-jt-7-gear-oil-yet/ Share on other sites More sharing options...
rick harper Posted May 21, 2015 Share Posted May 21, 2015 Fuller Roadrangers use 50W Quote Link to comment https://www.bigmacktrucks.com/topic/40110-has-anyone-used-the-mystic-jt-7-gear-oil-yet/#findComment-290713 Share on other sites More sharing options...
david wild Posted May 21, 2015 Share Posted May 21, 2015 Ya but down here the in south they all seem to want to put heavy gear oil in the trans then bitch in the winter about slow shifting, with heavy loads we have used heavy oils but the lucas seems to stop the boiling over best, yes we have had trans. puke oil out the breather in the summer especially out in TX, rears too. Lucas stops the problem. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/40110-has-anyone-used-the-mystic-jt-7-gear-oil-yet/#findComment-290742 Share on other sites More sharing options...
theakerstwo Posted May 21, 2015 Share Posted May 21, 2015 A lot of guys will tell you to use 85/90 mutigear oil but it will eat the hi/low synchronizer facing. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/40110-has-anyone-used-the-mystic-jt-7-gear-oil-yet/#findComment-290744 Share on other sites More sharing options...
farmer52 Posted May 21, 2015 Share Posted May 21, 2015 Eaton is adement about using 50W lube in their transmissions. Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment https://www.bigmacktrucks.com/topic/40110-has-anyone-used-the-mystic-jt-7-gear-oil-yet/#findComment-290745 Share on other sites More sharing options...
b61mack Posted May 22, 2015 Share Posted May 22, 2015 about 10 years ago for 2-3 years I thought you use 85-140 in my RTO14613 and it seem like the transmission ran hotter then I found out It was to use 50w which seems to run cooler, but like glen said I ate up the synchronizer, when you let of the petal it would fall out of gear. Quote Link to comment https://www.bigmacktrucks.com/topic/40110-has-anyone-used-the-mystic-jt-7-gear-oil-yet/#findComment-290764 Share on other sites More sharing options...
slingblade Posted May 23, 2015 Author Share Posted May 23, 2015 in the roadranger repair manual it recommends 50wt for extreme cold climates,85/140 is a bit too thick here for the winter,they did mention that the EP additives cause seal issues if the oil gets over 250 degrees,not an issue with mine,im already experiencing issues with the hi/lo syncro and slight delay going into hi,i listen for the clunk before going back on the throttle and i does good,sometimes i press the clutch to make sure that theres no preload on the gears when going into hi range which also helps, Quote Link to comment https://www.bigmacktrucks.com/topic/40110-has-anyone-used-the-mystic-jt-7-gear-oil-yet/#findComment-290902 Share on other sites More sharing options...
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