CM2250 gear lube reccomendation

[flatbed94kid]

(10-06-2017 )JMBT Wrote:  Ok, I just finished re-reading Rawze's thread about gear lube. I demandated a few months back and have changed the oil 3 times in the last 30K to try and clean out all the soot from 600,000 miles of EPA ignorance. Now the oil is clean as a whistle and I will go back to 15-18K intervals. Now that the engine is cleaner inside I am ready to start adding some gear lube for the added benefits Rawze has spoke of.
Should I run a GL-4 or GL-5 since I am demandated? What viscosity 85W90? Also, do you guys running gear lube adjust the type or amount in winter vs. summer? Is there anyone out there running a Deman CM2250 that can tell me what they have found works well?
Thanks!

I just poured some 85w 140 supertech from walmart in mine today. Pretty thick stuff.