Mechanic says the rear differential is going bad do you have to replace whole thing or can it be repaired and which is cheaper

 

I think rebuilding would cost more than to replace it, but why not ask your mechanic? Get a quote from them and search for prices of the diff itself.

 

Look up PuddyMod for the expert on S2000 diff rebuilds.

 

Labor is the killer on rebuilds. Used AP2 differetials abound on Ebay for under $600, some under $400. Still gotta put it in the car.

http://www.ebay.com/itm/2007-HONDA-S...2d9839&vxp=mtr

-- Chuck

 

Without question just get a used one. You'll pay through the nose for a rebuild, and it may not even work out.

Taking the pumpkin in and out is a 2-3 hour job.

 

common suggested fluid for the differential ?

 

Billman suggests this: http://www.amazon.com/gp/product/B00...ilpage_o01_s00

Changing at 35k intervals.

 

Just bought a used one for my car. Does your diff fail the spin opposite directions test in the manual?

I change my fluid every 15k but I also Autocross. 30k change came up just a few thousand after I bought the car and Goop came out. So not a fan of waiting that long. Not sure if the 75W-90 Mobil 1 was in it when I bought it though.