2019 C7 'Ray, M7, no eLSD non-Z51 (although applicable to most if not all C7 M7's)
At 29,000 Km's, and before winter hibernation I did the usual twice-annual Oil & Filter change - plus a full M7 drain and refill on Transmission and Differential. Examination of the trans oil showed that it was still fairly RED in colour with no discernable metal but lots of sludge on the drain/fill plugs. The old diff oil was silvery-grey in colour, and also with a fair bit of sludge on the lower plug.
My mechanic (the guy's a genius with engines and trannies - builds his own race engines and configures his own racing transmissions - although he's a Dodge fan I don't downgrade him for that) made sure to purge the diff with new 75-90 after draining with the plugs still out, to make sure any remaining contaminants were mostly gone - and did the same with the tranmission.
In went the synthetic 75-90 to the differential. The transmission got an infusion ofliquid gold Royal Purple Synchromax after purging with new off-the shelf Dexron III ATF with the plugs still out, again just to flush out as much of any remaining contaminants as possible. I thought the Royal Purple was overpriced at first, but have changed my tune on that after feeling the results.
What a difference in the shifting! Where the transmission was extremely notchy when cold, and even a bit when hot, it was so smooth on my extended drive back home that you could almost mistake it for an automatic, no hesitation with the shifts, smooth run through the gates, no need for extended clutch work or clutch disengagement time. It even slipped right into 1st at a stoplight with no resistance - it's never been that good before even when new coming off the dealer lot.
Now I can't wait for next season to really give it a workout - I'm hoping that I might still get some road time before the road coverage is discontinued before the end of October and it goes to sleep in the garage for the winter.
LLC
At 29,000 Km's, and before winter hibernation I did the usual twice-annual Oil & Filter change - plus a full M7 drain and refill on Transmission and Differential. Examination of the trans oil showed that it was still fairly RED in colour with no discernable metal but lots of sludge on the drain/fill plugs. The old diff oil was silvery-grey in colour, and also with a fair bit of sludge on the lower plug.
My mechanic (the guy's a genius with engines and trannies - builds his own race engines and configures his own racing transmissions - although he's a Dodge fan I don't downgrade him for that) made sure to purge the diff with new 75-90 after draining with the plugs still out, to make sure any remaining contaminants were mostly gone - and did the same with the tranmission.
In went the synthetic 75-90 to the differential. The transmission got an infusion of
What a difference in the shifting! Where the transmission was extremely notchy when cold, and even a bit when hot, it was so smooth on my extended drive back home that you could almost mistake it for an automatic, no hesitation with the shifts, smooth run through the gates, no need for extended clutch work or clutch disengagement time. It even slipped right into 1st at a stoplight with no resistance - it's never been that good before even when new coming off the dealer lot.
Now I can't wait for next season to really give it a workout - I'm hoping that I might still get some road time before the road coverage is discontinued before the end of October and it goes to sleep in the garage for the winter.
LLC
