Waranty is almost up and I would like to drain and replace the fluids. Checking for metal etc. When replacing, any real diff between GM fluids or aftermarket synthetics? Aftermarket all claim better performance and cooler temps. In the real world, will I notice this.
Thanks

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by primetime:
<strong>Waranty is almost up and I would like to drain and replace the fluids. Checking for metal etc. When replacing, any real diff between GM fluids or aftermarket synthetics? Aftermarket all claim better performance and cooler temps. In the real world, will I notice this.
Thanks</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No. I have yet to change mine, but I here good things about the Royal Purple brand. Other than that, most of what I have seen is guys going back with the stock fluids.

 

i was going to change my differential fluid this week but i dont know how much it takes. i heard either 3 or 3.5 qts. i dont want to have to buy too much when RP is $9.76 a qt.

 

anyone?

 

It says in the manual actually to use synthetic diff fluid. (pretty sure Mobil 1 75W-90) don't forget to buy the oil for the posi to add also if you drain the entire rear end. You will burn out your posi w/o it. As far as tranny goes...B&M Trickshift fluid if you have your entire tranny flushed (torque converter and all) peace.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by graygmc:
<strong>anyone?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">2.125-2.3 quarts or so...do not fill it until it drips out of the fill hole as that was the procedure on pre-'99 8.5's. Fill it per the specs on the plastic tag above the fill hole. I dipped in an allen wrench to make sure it was the proper depth below the fill hole when I did mine. Be sure to take the cover off you'll find a lot of crap on the magnet.

 

For transmissions, any DexronIII will be sufficient. Although I use Redline synthetic DexronIII ATF in all mine other than the Allison which I use Allison's recommended sythentic made by Castrol called Transynd.

 

ok cool. i just didnt know how much to buy before i did that project.

 

I saw a comparison on a car show about oil vs. syn. they claim if you replace the Engine oil, tranny fluid and rear end with syn. you'll gain almost 10HP. They showed the dyno tests.

 

10hp sounds REALLY high for just changing fluids. Do you have any dyno numbers or web page so we can all see this? <img border="0" alt="[Truck]" title="" src="graemlins/gr_truck.gif" />