Land pride 5615 rotary cutter gearbox oil?

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Aug 15, 2018
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Texas, United states
Hello all and thanks for the add to the forum. I'm a small engine mechanic and competition bbq cook. I just recently purchased a new rotary cutter and have about 40 hours on it now. In the book it says to use GL-4 hpypoid or better 80w-90 gear oil. I'm a avid believer in synthetic lubricants. Recently I read a study done by currie enterprises about why the high end racing rear ends had failed using synthetic gear oil and currie made a jig that measured the temperature of the actual gear teeth. They came to the conclusion that regular dino oil dissipated heat better out of the gears into the differential housing while the synthetic did not. Even though the synthetic gear oil is a little lower in temp, the gear itself was alot higher. With that being said I'm kind of at a crossroads here..... im contemplating running some mobil 1 SAE J2360 high dollar gear oil to deal with the extreme Texas heat and extended intervals. My shredder cuts worlds better @ 600pto rpm versus the regular 540pto rpm. The other day after a 40 acre pasture the gearboxes were so hot they almost sizzled my finger. I read that SAE J2360 gear oil is not reccomended for GL-4 applications because of the possibility of messing with syncronizers. I'm not worried about any of that. This thing has 3 gearboxes and one main divider box. I am hard on my equipment. I use it hard and run it hard. But I want to provide every bit of insurance I can to this $18k rotary cutter as far as thermal protection and shock loads from hitting random stumps, ant nests or whatever I run over. I read one key thing about running synthetic gear lube is better for seals since they run lower temps...... or is did Currie enterprises disprove that theory? Is there anything to gain by using this top end gear oil lubricant or should I just stick with regular old tried and true dino 80w-90?
 
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CT8

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Are there synchros in the gear boxes of the brush hog? I replaced a gear box on a 6 foot cutter last spring . I took apart the old box and there were no synchros. The gear boxes are all made in china. I run 85w-140 gear oil.
 

Jmoney7269

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No syncros...... those are to my knowledge only in transmissions..... not rotary cutter gearboxes. A rotary cutter gearbox is really nothing more than a differential that slings blades. Just wanting to know if there will be any long term benefit to running a really good synthetic oil like a SAE J2360 over regular gear oil?
 
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Beautiful setup. I'm a Kubota fan myself. I have no experience with this, but I believe a member here reported a while back that after sitting a while, their PTO driven gear boxes that had been filled with synthetic gear oil had light rust on the internals whereas the ones filled with mineral oil did not. Long term benefit? Change it when the manual says to and I'd argue to say no.. I'd venture to say you'd be fine with a GL-5 too as I doubt there's any yellow metals in the gearbox. NAPA has Sta Lube. It's a mineral 80w-90 GL4. By far the easiest to find here anyways. I've just used whatever has been on hand. GL-5 synthetic included.
 
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Oct 28, 2017
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Nice setup! I used to run a similar setup mowing roadsides for our local county public works. Make sure you have the mower deck adjusted properly, exactly as the manual states. I always ran at 540 rpm and it cut very good. In fact, it did a better job than the Alamo Flex-wings. Mystic JT7 or Shell Spirax are good gear oils.
 

Jmoney7269

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Aug 15, 2018
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Thanks MPARR! I did alot of research and always kept coming back to land pride. This thing cuts really well and has the double deck design that keeps the exterior from getting dinged up. Also it has one counterrotating blade that helps with winnowing. So the GENERAL CONSENSUS is to to use any EP 80W-90 and I will be fine? And no benefit from running the SAE j2360 gear oil which is one of the highest standards for military spec?
 
Joined
Apr 22, 2017
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South Texas, USA
I realize this is an old thread, and you may never read this but,,, My thoughts are: If you turn the gears faster, they get hotter. If it has "Omni" boxes like most of em seem to,,the 80w90 is borderline in out Texas heat according to the omni manual . They get too hot to touch just sitting in the sun. I am changing mine to 85w140. It don't get too cold for 85 weight here in south texas. I'm using a ModernAG 15' with probably the same boxes as you have. It cuts good even at 450rpm, but if the grass/weeds are tall and thick, it tends to windrow a little. Good luck.
 
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