Driveshaft/rear axle maintenance

Hello,
Slydog75,
Change the 75-90wt synthetic gear oil. Drain plug on bottom of gear box. and side fill plug. With bike up right. I always
flush the old oil out with new. Replace drain plug - torque to 25nm. (Drain plug with magnet on it- wipe off)
fill until oil runs out fill plug, replace fill plug torque to same as above.
Not necessary. I repeat process one week later. I usually change at every oil change.
oil is cheap……
 
Hello,
Slydog75,
Change the 75-90wt synthetic gear oil. Drain plug on bottom of gear box. and side fill plug. With bike up right. I always
flush the old oil out with new. Replace drain plug - torque to 25nm. (Drain plug with magnet on it- wipe off)
fill until oil runs out fill plug, replace fill plug torque to same as above.
Not necessary. I repeat process one week later. I usually change at every oil change.
oil is cheap……
Dr
Hello,
Slydog75,
Change the 75-90wt synthetic gear oil. Drain plug on bottom of gear box. and side fill plug. With bike up right. I always
flush the old oil out with new. Replace drain plug - torque to 25nm. (Drain plug with magnet on it- wipe off)
fill until oil runs out fill plug, replace fill plug torque to same as above.
Not necessary. I repeat process one week later. I usually change at every oil change.
oil is cheap……
Drain plug only needs to be torqued at no more than 5 or 6 nm. The center of the plug is hollow . It has magnetic material in the end of it. Be careful when you are tightening it. Will break very easily. I use a 1/4 in drive ratchet to replace the plug.
Be careful.
 
There are some reports of busted drain plug bolts. They are fragile. I take off the whole final drive and drain it through the fill plug. I use a syringe to refill it with the spec volume. It's a good time to inspect the splines, clan them and relube them. Good time to clean the rear caliper pistons. If it has not been done, it's time. Final drives eat un-manitained splines. They are not an easy find. Good luck.
 
I will add about being careful when tightening that magnetic plug. I broke mine off the very first time I changed oil on mine. Having a hollow bolt to hold the magnet is a stupid piece of work. Anyways you cannot get the broken piece out without taking the diff. apart, there are braces molded into the diff. for strength & not enough clearance from that to the ring gear for it to pass. I bought just a bolt for the drain hole then and did what I do to most of my bikes plugs, drill a small hole horizontally thru the head to use a safety wire to keep it from turning so as to be sure that it won’t vibrate out while going down the road. The hole that it goes into is countersunk so I cut the head off a phillips head bolt & tig welded it onto the drain bolt. I then drilled a small hole thru the filler plug head & just safety wire the two together.
I didn’t see much need for that magnet as I change that oil very often….it takes so little.
 
Had my Rocket 16 years. Done 50,000km. Not sure when last final drive oil change was done! Never mind, what I did do was give both fill and drain bolts/plug a couple of good squirts of WD40 and let sit for 2/3 days. Had no issue removing the bolts although the filler plug was very tight. Used BelRay Hypoid 80/90 gear oil as the replacement. The old oil very black, yet no metal shavings on magnetic drain bolt, just some “sludge”. I will do a thousand k’s and then replace again as I found the diff only requires 75 mls, not 170 as per my manual, which I do find rather odd!!
 
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