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Royal Purple vs Syngear

2K views 16 replies 8 participants last post by  HarvestingInternationally 
#1 ·
I need to replace the diff cover. I was gonna use Royal Purple to refill with but I have a bucket of Castrol SYNGEAR in 50w and in 75-90w. Anything objections to using that instead?
 
#5 ·
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#6 ·
From experience Royal Purple is a performance oil. So is Amsoil. We used this in our drag boats. If you got a HiPo car its great. I dont mean to knock, but Mobil1 tends to be bottom teir of the synthetic oils. It finishes almost dead last in every independent test. I dont know if RP or AO will be good or not for your HD towing, but they both do provide excellent lubricity. I would try to find a good heavy duty gear oil or some test of RP and AO in those situations as they are actually great companies.
 
#7 ·
For what its worth, Xtreme Diesel recommends both Amsoil AND Royal Purple fluids for our heavy duty trucks.
 
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#8 ·
I used royal purple in my trans am when I had it...never was impressed. It has Harland sharp rocker arms and with royal purple it made noise. When I switched it to Mobil 1 it cleans a lot of crap out of the engine and quiet down the top end. It's just my experience. I put RP in the rear if my truck and transfer case. I don't like it. Maybe it's just me
 
#9 ·
Like I said, we used it in EXTREME performance conditions. 11k+ rpms. Same with Amsoil. HD use, eeehhhh My oil I stick with Delo 400 or Rotella. Now my CJ7 with the AMC 304, I love the RP. 10W-30 all they way and its great. I just wouldnt use performance fluids in a application that requires the longevity while taking the beating we give our trucks.....
 
#10 ·
I have Mobil 1 in mine and like it.
My truck weights in at 12k lbs every day and sometimes tows a 10k dump trailer.
 
#11 ·
#12 ·
So a test done for amsoil with results stored at amsoil says that amsoil is the best? Strange....
 
#15 ·
Then he had another problem. Not a single oil on the market will cause that. I ran two f150s with 5.0s with cheap cheap 10w-30 oil and got 300k miles out of both and sold them running. Any oil will make a motor last if u change it like your supposed to. I'll never blame an oil for blowing up a motor....it's always something else.

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#16 ·
#17 ·
Changing your oil is like cheap insurance
 
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