killbee

I am getting ready to install my 3:73 FMS gears in my 05. Question is when will I need to change the gear oil after the install and should I run non-synthetic as the break-in first or start with synthetic?

shooter23

um...well, you will have to drain the oil when you do it...why would you not just put new stuff in?

Dont worry about the fluid for the "break-in"...just drive it and you'll be good to go...

Put in whatever fluid you want (as long as its the right weight)...i would go synthetic...mainly becuase it wont break down as easily as non-synthetic...but neither will really aid or hinder in the break-in period.

killbee

Maybe I should re-word this. I am wondering ifyou have a break-in period with new gearsand you have to change the oil after the break-in. I have heard some people say to break-in the gears withnon-synthetic then change to synthetic afterwards.Then some have said to just put the synthetic straight in and not worry about changing for at least30K miles.

zkiller

not necessary

mygt500

I would get the gears done and switch to synthetic for the install and after the break-in continue to use the synthetic but I feel it is not necessary after break in to change the gear oil.. Did you change the stock gear oil after you broke the car in???? Why would it suddenly be necessary after a gear install that is done right. If you have whine take it back until it is right.....hope this helps and I am sure someone else will disagree but afterall it is JMO.