My blazer's about to roll 50k miles, and I figured I would change out the fluids. Im gonna do the trans fluid and gear oil next week in my autoshop class. Just wondering what brand you recommend or if it really matters? Also what weight fluid does the rear axle take? Another quick question, when do you recommend i change the plugs and wires? Can I wait till 60k or should i do it sooner? It runs pretty smooth and idles pretty smoothly as well.

Thanks

 

If you want the best of the best, go Amsoil. Pricey, yes - but there's a reason for that. If you live in a cooler climate & you want the best fuel economy, you can run Severe Gear 75W-90, or, if fuel economy isn't a concern &/or you live in a hot climate, or tow frequently, or otherwise abuse the diff I'd run the 75W-110. I don't see any reason to run the 75W-140 unless you live in Phoenix & do drag style launches with a V8 under the hood, but it's there for those who want it. I run the 75W-110 in my '07 Silverado in both the front & rear diffs, and it works great. 4x4 engages perfectly even in sub zero temps.

For the tranny, run Synthetic Fuel Efficient Automatic Transmission Fluid.