I am planning on changing the fluid in my rear diff this weekend. I have a vacuum pump that I have thought about using to remove the old oil without having to remove the cover. Is there any reason why I should not do it this way?

 

I suppose you could do it that way. There's a big magnet on the inside cover that's been collecting metallic mud for the past couple of years though, so it would be a good idea to clean it before replacing nice fresh gear oil. Whichever way you go, jack up one side, then the other to get the oil out of the axle tube.

 

Pull the cover to change it. Gives you a chance to see if there is anything wrong inside... if you want, suck it out first so it doesn't all pour out on you when you pop the cover... ;D Also, like Tom said, jack up each side so you get the maximum amount of old stuff out!<br><br><br>Tony

 

was thinking about when i change the diff fluids to replace with a synthetic what do yall think what are the advantages of the synthetic?

 

I'd recommend synthetic fluid. I know the Ford ambulances we have with Dana 80 rear axles came from the factory with synthetic in 'em.

 

Dodge reccomends synthetic if towing. Funny thing though, I changed mine last weekend (amsoil 75-140) and was told by many the friction modifier wasn't needed with it. Since I changed it my chuck is chattering like crazy when I accelerate through turns.<br>Tim

 

Especially with LSD's, it's recommended to drive severval tight figure of 8 patterns in a parking lot after changing the fluid to get the new stuff worked in. If chattering continues, then a friction modifier needs to be added. Just enough though, too much will render the LSD useless, or ineffective.

 

I changed mine and filled with Royal Purple 75-140. No friction modifier added, no chatter. I think whether or not you need the modifier may depend on the condition of your lsd clutches.<br>JMHO<br>wk