snth. gear oil
bcowanwheels said:
DONT GO WITH ANTIQUE LUBE ! PUT SYNTHETIC STRAIGHT 50 WEIGHT TRANS OIL IN IT LIKE THE MODERN SEMI TRUCKS USE. IT WILL RUN COOLER, SHIFT EASYER AND LAST FOREVER. BOB
Let me warn you all!!! Better DO NOT USE synthetic gear oil in the deuce tranny, unless you want to learn fast, the hard way!
This is what happened to a friend of mine: he got his multifuel deuce in a public auction and it came out the 3053A had a broken 5th od. gear. After replacing the damaged parts he decided to switch to 75W-90 full synthetic GO (Castrol) being very confident that this would be the perfect choice for a modern long-life lubricant to have his gear box run cooler, quieter and well protected against any “abuse”. For the following 2000 miles (work and play) he’d never noticed any bad symptoms or problems, until one day after just a short hwy trip, in 5th OD , loaded, he almost fried his transmission! When it happened, he said it felt like someone invisible had stepped on the brakes and a suspicious smoke and burned smell was coming out from the shifter boot. After disassembly and inspection it appeared that 2nd gear had been severely seizing on the mainshaft, almost welded together! This transmission wasn’t new anyways, so he replaced the complete box with a “like new” takeout, put in the same (long-life?) oil he had drained from the first one (it looked very clean) and went for the next load. After only 20 miles the second tranny gave up it’s ghost, exactly the same failure! (poor lubrication…!?) After disassembly everything looked new except for the blue colored mainshaft where 2nd gear turns. So he took both gear and shaft to a machine shop where they just polished the affected areas. Wear tolerance was still acceptable so everything went back in. This time he went back to the good old SAE 90 gear oil, (who knows, may be…?)
To make it short: from that day on (almost 4 weeks ago) the truck has been running fine like nothing ever happened!
Could somebody please explain? Anyone else with a similar experience?
Since lately I was using synt. oil too (LM 75W-90), I got really concerned. So I consulted the technicians at Liqui Moly in Germany. Two weeks later the answer came: We do NOT recommend using our synthetic gear oils in early transmissions! (for reasons that don’t have anything to do with what happened!) Needless to say I drained mine and refilled with 85W-90 (Chevron), better sooner than to late…
Gerhard