I just bought a 2000 GMC Jimmy Diamond with only 66k miles. I have had some mechanics tell me to just change all fluids to be safe because the vehicle is 14 years old and some say to just leave it if it looks fine.

The tranny fluid looks and smells fine, so should I just leave it or change it to be safe. Diff fluid too?

Also what is the best oil to run?

Thanks!

 

get it changed. ask for a pan change with filter,NOT a flush.

for oil. whatever you wanna run and is on special. brand dont matter as long as its done at 3k miles.

 

Why not a flush?

 

If this is your first service,pan change..

there is junk in your transmission,that helps you (clutch packs). Lots of times if you flush it all out,it can actually hurt you more then anything. In my opinion with my years dealing with this mess,unless its been maintained even under 100k miles, just change the pan service. its about 5 quarts worth. lil less then the trans can hold. helps recondition the trans,and not remove what could be helping the clutches.

 

What about the diff fluid? Change that too with only 66k miles on the rig.