- Oct 18, 2011
So I did a big fluid day (coolant, engine, rear diff, tranny) yesterday, and used castrol hypoy C 80w90 (MT5, synthetic blend) for the tranny and my diffs. The diff is happy again, but my transmission now feels like it came off of a tractor. Very notchy, when it's cold I am almost catching the synchro in second off guard (never had transmission issues before the fluid change) Did I use too heavy a weight for Seattle driving? The shop ran out of Hypoy C in 80w90, so I had to mix in a quart of valvoline synthetic blend 80w90. Could this be the culprit? Could it be that I used MT5 instead of MT4? Should I really drop the coin on synthetic, and does it make that large of a difference in tranny feel? This is just my truck, not a race car, so I've always used mid grade products with it and just kept on top of maintenance. The truck has a capacity of 7 quarts, but using the drainplug only evacuates 4. If I need to get rid of what I put in or change the weight (previous weight/make that I mixed the new stuff in with is unknown) should I just drop the pan and do the filter/gasket while I'm at it? or just do a couple more flushes over this month to get things mostly right?