Transmission and rears lube.

[Rawze]

950k miles later, I have always used 75/90 synthetic in rears and replace the oil every 200k miles.

Trans, i put 50 wt synthetic and replace it at 200k intervals too.


OTR trucks, recommendation is 250k miles, LTL or local truck, its as high as 500k miles because of less constant heat buildup.