I don't think a fluid change would cause it, not unless you did something totally weird like used ATF instead of 90w. I've learned to accept and embrace the rear main seal leak in my '52. wink


Matthew 6:33

1952 Chevy 1/2-ton 3100
Late '55 235/SM420/torque tube 3.55
Dalton Highway survivor (using original 216)
www.truckwithaheart.com