Nissan Repair: Fluid changes

Question
I have a 2002 Infiniti Qx4. The owners manual does not indicate a replacement interval for transmission fluid, just inspecting it periodically. I had it chaty 85,000. Should I have it changed or leave it alone? I have no problems with the transmission. Also, what about 4 wheel drive service? I had it serviced at 56,000 miles 3 years ago. I never go off road. Does this need to be serviced again? Thanks

Answer
Hi Jeff -

Normally replacing transmission oil is by a case by case basis, depending on use and wear of the vehicle. 2 cars can have 100K miles on it but the amount of freeway driving vs stop and go, or inclines vs flat road will make a difference. Normally if you pull out the dipstick and inspect the color of the oil, you can determine if it needs replacing. The oil should be bright red. If it is closer to maroon or brown, replace the oil. However as a general rule, Once a year should be more than safe to change the oil.

As for your 4 wheel drive, the 3 years are good. Normally if you do not go off road or use the system, it should be OK, but the oil should be replaced as it gets old and loses its properties.  

Hope this helps -
aloha
Calvin