Originally posted by Texas Diesel
From what I have been told, HD motor oil contains phosphorus which is harmful to yellow metal used in synchronizers. Another choice is RP Synchromax which is formulated to go in transmissions (synchronized) and transfer cases and it is 100% friendly to synchronizers, it is suggested to replace ATF and motor oil in transmissions. It is fully synthetic and desingned to be a gear lube instead of using motor oil in a synchronized transmission. I just got a case and put it in my NV-241HD. Now my w4d engagements are 100% grind free. I dont know where to read about ti on the web but if you send your email address I'll send you the Adobe file that describes it.
I feel much safer having a oil designed to go in a transmission than using engine oil there.
Beware: The only approved oil is Texaco MTX (1874), ANY other oil puts your warranty in jepordy.
-- email address removed -- put synchromax in the subject line and I'll email the info.
The Texaco MTX is a fully synthetic 5W-30 motor oil. Cross the API spec on is. The sticker on the side of the transmission can not be enforced by Chysler according to federal law. Go on the FTC web site and look up the Magnusson-Moss Act. In layman's terms it states that an OEM cannot require a consumer to use an OEM part or fluid in order to maintain warranty coverage unless that part or fluid is provided free of charge.
Steve
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