Going to start stocking up on 75W90 for the different on my truck, my two choices are RP 75W90 or Amsoil 75W90.
Which would you chose? Why is RP priced higher than Amsoil?
Which would you chose? Why is RP priced higher than Amsoil?
Gear oil questions?
- Thread starter WillB
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gathermewool
Site Donor 2023
Are those your only choices?
Are you stocking up for one change, a couple of rapid changes to clean it out, or because you off-road and will see lots of changes due to water intrusion?
Are you stocking up for one change, a couple of rapid changes to clean it out, or because you off-road and will see lots of changes due to water intrusion?
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I've tried both. Go with Amsoil Severe Gear 75W90.
Yes, I won't run the other off the shelf brands for various reasons. Castrol dumped John Force, not supporting them, no use for QS.
Pennzoil is equal to Amsoil price, is it just as good?
Truck has 63,000 miles on it - 2011 GMC 1500 - fluids are original.
Pennzoil is equal to Amsoil price, is it just as good?
Truck has 63,000 miles on it - 2011 GMC 1500 - fluids are original.
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My experience:
Mobil 1 made the rear diff whine and made it noisy.
RP made it vibrate and gave it wheel hop.
Amsoil made it smooth as silk.
You could also go to the GM dealer and buy OEM fluid.
Mobil 1 made the rear diff whine and made it noisy.
RP made it vibrate and gave it wheel hop.
Amsoil made it smooth as silk.
You could also go to the GM dealer and buy OEM fluid.
Originally Posted By: WillB
Yes, I won't run the other off the shelf brands for various reasons. Castrol dumped John Force, not supporting them, no use for QS.
Pennzoil is equal to Amsoil price, is it just as good?
Truck has 63,000 miles on it - 2011 GMC 1500 - fluids are original.
I changed my rear diff fluid at 70K. It was original too. Milkshake chunky consistency. Plan on a flush first. Use SuperTech 75W-90 for the flush and/or the actual fill. I plan to change mine every 18K with the ST. If you use ST then you can refresh without worry on cost. I do the same (shorter OCI) with my transmission but use higher quality oils for that (Honda DW-1 and Havoline MD-3 between two vehicles).
Yes, I won't run the other off the shelf brands for various reasons. Castrol dumped John Force, not supporting them, no use for QS.
Pennzoil is equal to Amsoil price, is it just as good?
Truck has 63,000 miles on it - 2011 GMC 1500 - fluids are original.
I changed my rear diff fluid at 70K. It was original too. Milkshake chunky consistency. Plan on a flush first. Use SuperTech 75W-90 for the flush and/or the actual fill. I plan to change mine every 18K with the ST. If you use ST then you can refresh without worry on cost. I do the same (shorter OCI) with my transmission but use higher quality oils for that (Honda DW-1 and Havoline MD-3 between two vehicles).
gathermewool
Site Donor 2023
What kind of service?
I took it for what it was worth, but the Redline representative said that their shock-proof gear oil was overkill for my STI with limited slip differential (Torsen gear-type.) He stood to gain more money on a more-expensive product, but recommended the cheaper gear oil for a DD. I did let him know that most of my driving was commuting, but that I did plan to rally-cross occasionally and even head to the track in the future, but that didn't change his recommendation.
I tend to go overkill with these things and ended up going with Motul Gear 300 (best gear oil...on paper, at least.) It might be; however, that the cheaper Amsoil variant is way more than what is needed for typical putzing about on the highway and even a little bit of soft off-roading. The benefit for me, when I change the gear oil in my Forester to Amsoil or Redline, will be that I won't plan on changing it again.
I took it for what it was worth, but the Redline representative said that their shock-proof gear oil was overkill for my STI with limited slip differential (Torsen gear-type.) He stood to gain more money on a more-expensive product, but recommended the cheaper gear oil for a DD. I did let him know that most of my driving was commuting, but that I did plan to rally-cross occasionally and even head to the track in the future, but that didn't change his recommendation.
I tend to go overkill with these things and ended up going with Motul Gear 300 (best gear oil...on paper, at least.) It might be; however, that the cheaper Amsoil variant is way more than what is needed for typical putzing about on the highway and even a little bit of soft off-roading. The benefit for me, when I change the gear oil in my Forester to Amsoil or Redline, will be that I won't plan on changing it again.
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Originally Posted By: gathermewool
I tend to go overkill with these things
^^Same here. Transmissions and differentials I spare no expense. I change mine out once a year.
I tend to go overkill with these things
^^Same here. Transmissions and differentials I spare no expense. I change mine out once a year.
RP 75W90 or Amsoil 75W90 ? Amsoil for sure.
I use Amsoil gear lubes in my vehicles. It doesn't get changed often so an extra few bucks for Amsoil lubes are worth the money.
My truck gets used as a truck, it tows to the max a few times a year, hauls everything from wood if we run out to top soil, gets driven 25,000+ miles a year. And gets a work out often during the winter in deep snow.
Sounds like Amsoil Severe Gear 75W 90 in both diffs is the way to go. Best part is Amsoil is $6 per bottle cheaper than RP up here.
Sounds like Amsoil Severe Gear 75W 90 in both diffs is the way to go. Best part is Amsoil is $6 per bottle cheaper than RP up here.
Have you considered Red Line?
gathermewool
Site Donor 2023
Originally Posted By: WillB
My truck gets used as a truck, it tows to the max a few times a year, hauls everything from wood if we run out to top soil, gets driven 25,000+ miles a year. And gets a work out often during the winter in deep snow.
Sounds like Amsoil Severe Gear 75W 90 in both diffs is the way to go. Best part is Amsoil is $6 per bottle cheaper than RP up here.
Severe Gear or Shockproof sound like good choices. I'd go with whichever is cheapest.
My truck gets used as a truck, it tows to the max a few times a year, hauls everything from wood if we run out to top soil, gets driven 25,000+ miles a year. And gets a work out often during the winter in deep snow.
Sounds like Amsoil Severe Gear 75W 90 in both diffs is the way to go. Best part is Amsoil is $6 per bottle cheaper than RP up here.
Severe Gear or Shockproof sound like good choices. I'd go with whichever is cheapest.
dnewton3
Staff member
Originally Posted By: WillB
Going to start stocking up on 75W90 for the different on my truck, my two choices are RP 75W90 or Amsoil 75W90.
Which would you chose? Why is RP priced higher than Amsoil?
Well - this is just like any other "What's the best synthetic my money can buy?" thread ....
Typical of most folks, you're going about this booty-backwards. Don't pick a fluid and then try to cram it into your use. Rather, analyze your use, and then see what fluids will meet your needs. Because there is a HUGE difference between wants and needs. I would even recommend getting some UOAs if you really want to tailor your lube selection to a specific application.
Now - if you just "want" a syn, and a very expensive one, to make yourself feel better, then stop reading this post and just go do whatever makes you feel good.
If you'd rather make an educated decision, then determine your OCI plan and work from there. Get a couple UOAs and establish a baseline of performance; understand what is and is not working, so that you have a reasonable interpretive position. Syns can offer some good options if OCI extension is your goal. But if you're not going there, then conventional lubes can be every bit as decent at protecting your diffs for a lot less money.
Think I'm wrong? Look this over ...
http://p-r-i.org/other-programs/automotive-qpl/lubricant/
open the "current QPL listing" and browse all the approved lubes. These all meet SAE J-2360, which is a very hardy and robust standard not just about what's in the bottle, but how the fluid actually performs in terms of wear control, foaming, vis retention, etc. It's based on a MILspec process. And if you look closely, you'll see that there are some good dino gear lube choices that meet the very same specs as many popular syns!
Do you "need" a syn? Can't tell you for sure; that would depend upon your OCI plan. Do you "want" one? Sounds like "yes" to me.
But if you're only satisfying a "want" here and not a "need", then just buy whatever tickles your fancy. When a "want" is the itch you need to scratch, then just pick something that makes you feel good, because that's about all it's good for.
Going to start stocking up on 75W90 for the different on my truck, my two choices are RP 75W90 or Amsoil 75W90.
Which would you chose? Why is RP priced higher than Amsoil?
Well - this is just like any other "What's the best synthetic my money can buy?" thread ....
Typical of most folks, you're going about this booty-backwards. Don't pick a fluid and then try to cram it into your use. Rather, analyze your use, and then see what fluids will meet your needs. Because there is a HUGE difference between wants and needs. I would even recommend getting some UOAs if you really want to tailor your lube selection to a specific application.
Now - if you just "want" a syn, and a very expensive one, to make yourself feel better, then stop reading this post and just go do whatever makes you feel good.
If you'd rather make an educated decision, then determine your OCI plan and work from there. Get a couple UOAs and establish a baseline of performance; understand what is and is not working, so that you have a reasonable interpretive position. Syns can offer some good options if OCI extension is your goal. But if you're not going there, then conventional lubes can be every bit as decent at protecting your diffs for a lot less money.
Think I'm wrong? Look this over ...
http://p-r-i.org/other-programs/automotive-qpl/lubricant/
open the "current QPL listing" and browse all the approved lubes. These all meet SAE J-2360, which is a very hardy and robust standard not just about what's in the bottle, but how the fluid actually performs in terms of wear control, foaming, vis retention, etc. It's based on a MILspec process. And if you look closely, you'll see that there are some good dino gear lube choices that meet the very same specs as many popular syns!
Do you "need" a syn? Can't tell you for sure; that would depend upon your OCI plan. Do you "want" one? Sounds like "yes" to me.
But if you're only satisfying a "want" here and not a "need", then just buy whatever tickles your fancy. When a "want" is the itch you need to scratch, then just pick something that makes you feel good, because that's about all it's good for.
There is no Red Line available locally.
This past winter was our coldest in 118 yesrs. February never got warmer than -30, March was not much warmer.
The truck left the factory with syn in the rear, and will get it in the front. Not keeping two different oils on the shelf. Living in the Cold climate that we do up here, there is no way I will not see the payback on it, and the advantages it has to offer.
There is a Reason why GM switched to their cold climate power steering fluid, the conventional stuff caused steering lines to blow off on cold starts.
At 25,000+ miles a year, I'll change them again in three years.
The truck left the factory with syn in the rear, and will get it in the front. Not keeping two different oils on the shelf. Living in the Cold climate that we do up here, there is no way I will not see the payback on it, and the advantages it has to offer.
There is a Reason why GM switched to their cold climate power steering fluid, the conventional stuff caused steering lines to blow off on cold starts.
At 25,000+ miles a year, I'll change them again in three years.
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