I imagine that other manufacturers ball-diff grease would be OK, so long as it is 'really' ball-diff grease.. Using the wrong grease in the diffs will make them function incorrectly.. Ball-diff grease will thicken under friction and supply the right lubrication and resistance for a ball-diff assembly.. If you can, stick with the Tamiya ball-diff grease.. I bought an extra large tube for future use and it has functioned perfectly in my build for years now..
You should not have to re-tension the belts when you switch to a higher performance motor. Just make sure the belts are equally tensioned between the front and rear.. They should not be so tight that you can pluck them like a guitar string and not so loose that the teeth can slip under acceleration.. Adding the DB-01 Belt Tensioner Hop-Up can prevent problems.. The Hop-Up doesn't really change the tension on the belts, but it does help keep the belts more captivated near the layshaft to prevent the teeth from skipping around the pulleys..
As for your rear diff.. If you remove it from the car, make sure it is tight enough so that you cannot turn the center pulley by hand while the diff joints are locked in place (slide a couple of allen keys between the slots on the joints). If the pulley turns too easy while the diff joints are locked, then it is too loose.. Tighten it down a bit more and test it again.. Don't overdue it though, an overtightened diff can get damaged just as easily as a loose one (diff balls get crushed, thrust bearing gets crushed, etc).
Hope this helps.
|