Hey guys, Just ordered some 600 wt from the filling station. What is the best way to drain and flush out the old oil from the transmission/rear end drive line?? Car is in storage till spring, but i would like to get started with the oil change. Hope 4qts will be good enough. Thanks for the ideas as always...John

Ideally, you should drive the car and warm up the transmission and rear end. Otherwise the heavy oil will take a while to drain. I really don't see the necessity to flush either one. When warm remove the plugs (a bottom bolt on the rear end) and let drain for perhaps several hours. Refill with the 600 you purchased and you will be "good to go".

Ray,
I would add checking for metal particles in the drained fluid before refilling. Passing a magnet across the bottom of the container (if it is not magnetic) is less messy.

Many years ago,I got a small round magnet and used high strength epoxy to retain it in the original drain plug on the 4spd gearbox in my truck.
About every 2 years I let the gearbox drain o/night,re-fit the drain plug,fill with kerosene or diesel,then re-drain and refill with gearbox oil.
It's surprising just how many metal particles are on the magnet at the first drain,and how many more there are at the second drain.

Thanks for all the info, Thought I might use a halogen light to warm the case up (and oil) then drain?? Book said something about flushing out with light engine oil also adding pint of engine oil for winter (better shifting?)your thoughts on this for summer? Or better just use straight 600 Thanks.....John

Seeing you're laid up for a while, I'd suggest you drain the diff as Ray suggested. take the cover off and clean out all the residue in the bottom of the housing. When I did this in my 34 Master I found pieces of bronze from a collapsed cage, a magnet will not find this.
Check the coverplate for warping as due overtighening of bolts this tends to happen. Staighten it out as best you can. I use a 3mm thich neoprene cork gasket as it has more 'give' and I use a good quality wet gasket cement which helps.
Down here in Aus. we use 140 SAE which is basically the same as 600W.
Chris