I changed from OEM at 128,000. Now use Amsoil Series 2000 at 188,455, love it. Keep check with the MagHytec dip stick. No wear.
Preston
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96 3500, Black SLT, 5 speed, turbo diesel, , with US Gear overdrive, Rhino liner, Reese 15,000 lb. fifth wheel hitch, US Gear de-celarator exhaust brake, muffler elimination kit, Amsoil lub. , Mag-hytec rear cover, dual-remote by-pass filters, and Roadmaster Active system, AutoMeter Pyro & boost, Primeloc