CK5
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Synthetics
- Thread starter AkMudr
- Start date
From my experience rebuilding heavy truck transmissions...
It's apparent when you disassemble a high-mileage gearbox, whether it was run on petro or synth oil. Wear patterns on the synth-lubed gears looked cleaner & smoother. Everything in the unit was cleaner. In general, there were more re-usable gears & parts from a synth box than a petro box.
But the worst were the ones that had a mix of petro & synth oil in them, and were run hot. The heat caused the synth to react with the petro and "cook" it, causing heavy sludge/tar-like deposits on everything. Quite a few of the trannies I saw in this condition were removed from the truck due to "won't shift". Well no kidding, there's tar gumming up the sliders on the mainshaft that's so thick & nasty I can't remove it with a hammer....!
The moral of that story - Don't mix synthetic and petroleum lubricants in the same unit.
It's apparent when you disassemble a high-mileage gearbox, whether it was run on petro or synth oil. Wear patterns on the synth-lubed gears looked cleaner & smoother. Everything in the unit was cleaner. In general, there were more re-usable gears & parts from a synth box than a petro box.
But the worst were the ones that had a mix of petro & synth oil in them, and were run hot. The heat caused the synth to react with the petro and "cook" it, causing heavy sludge/tar-like deposits on everything. Quite a few of the trannies I saw in this condition were removed from the truck due to "won't shift". Well no kidding, there's tar gumming up the sliders on the mainshaft that's so thick & nasty I can't remove it with a hammer....!
The moral of that story - Don't mix synthetic and petroleum lubricants in the same unit.
I have thought about only runnin synthetic in my tranny, I figure the extra clutches and shift kit could use the good lube. But, $100 a pop to fill the damn thing doesnt really make me happy lol. I guess thats the price you pay.
