2005 Blazer

I just took my 2005 Blazer in for it's first oil change and to repair the issues with the fuel guage and tank today and the dealer told me that I should change the rear differential flud at 5,000 km. I didn't see this in the owners manual so I declined since there is only 4,000 km on it now. The cost was about $140.00 but that depends if it is synthetic or not. How do I find out the type of fluid ? and is this a real requirement? Any comments..........

i thought it was every 30 thousand miles you need to change your differential fluid.. not sure though..

Rear diff fluid changes on the same schedule as engine oil changes? They're trying to make easy money from sucker customers. Find another dealership for your service needs.

Rear diff fluid changes on the same schedule as engine oil changes? They're trying to make easy money from sucker customers. Find another dealership for your service needs.
I agree.
Open diffs rarely need a fluid change, and often will last the life of the vehicle in moderate use. 30 k miles would be reasonable to change a limited slip diff.
Also, changine the lube is very simple, $140 seems too steep.

Thanks all. I didn't have the fluid changed and i'll try somwhere else for the next service. Is anyone else with a 2005 having problems filling the tank to the full level ?

I would change the fluid to synthetic 75w90 at 5-10k to rid the rear diff from any filings from assembly and then you will be good for a long long time.