Gear oil viscosity and your differential
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""The diffs ran cooler by around 15-20C on long loaded""
Doug do you attribute the temp drop to the lower vis 90 vs 140 or the syn base stock?
bruce
Doug do you attribute the temp drop to the lower vis 90 vs 140 or the syn base stock?
bruce
Hi Bruce,
as the 80w-140 was also a synthetic I believe the temperature reduction was mainly due to the lower viscosity and its better flow characteristics
as the 80w-140 was also a synthetic I believe the temperature reduction was mainly due to the lower viscosity and its better flow characteristics
Thicker is not necessarily better. Old School still feels that you will get better protection by going thicker. But in fact if the flow is poor it does not handle the heat as well, leading to higher mps and quicker oil breakdown. If you have a premium 75-90 where called for, in most cases, will outperfrom the 75-140 of the same ilk?
Originally Posted By: salesrep
Thicker is not necessarily better. Old School still feels that you will get better protection by going thicker. But in fact if the flow is poor it does not handle the heat as well, leading to higher mps and quicker oil breakdown. If you have a premium 75-90 where called for, in most cases, will outperfrom the 75-140 of the same ilk?
Depends. Older axle designs were larger/heavier and didn't rely so much on the gear lube handling so much "cooling". Designs after say 1990's (for SUV applications) began to take CAFE into consideration more and more and weight reduction was moved higher up in the design criteria. Then axle lubricant flow was a means to cool overheat issues in some GM applications. Once this was proven as a feasable method of weight/cost reduction and performance enhancement it became the norm. Now GM has developed a standard for all synthetic lubricants to be used in all SUV models after 2006 I believe. So we are now seeing complete systematic design optimization of all criteria together to achieve least cost/optimal weight and acceptable performance with lubricants playing an integral part of the equation. A good example was when I converted my 2002 Suburban to 100% synthetic lubricants of the same (or close) viscosity and achieved an extra 1.5 mpg average. With a 5.3L flex fuel V8 I was averaging 17mpg city and 20.5 hwy. So back pre 1990 thicker probably was better because lubricant was only viewed in terms of durability and wear protection. Today we now know thicker is not better for current designs.
Thicker is not necessarily better. Old School still feels that you will get better protection by going thicker. But in fact if the flow is poor it does not handle the heat as well, leading to higher mps and quicker oil breakdown. If you have a premium 75-90 where called for, in most cases, will outperfrom the 75-140 of the same ilk?
Depends. Older axle designs were larger/heavier and didn't rely so much on the gear lube handling so much "cooling". Designs after say 1990's (for SUV applications) began to take CAFE into consideration more and more and weight reduction was moved higher up in the design criteria. Then axle lubricant flow was a means to cool overheat issues in some GM applications. Once this was proven as a feasable method of weight/cost reduction and performance enhancement it became the norm. Now GM has developed a standard for all synthetic lubricants to be used in all SUV models after 2006 I believe. So we are now seeing complete systematic design optimization of all criteria together to achieve least cost/optimal weight and acceptable performance with lubricants playing an integral part of the equation. A good example was when I converted my 2002 Suburban to 100% synthetic lubricants of the same (or close) viscosity and achieved an extra 1.5 mpg average. With a 5.3L flex fuel V8 I was averaging 17mpg city and 20.5 hwy. So back pre 1990 thicker probably was better because lubricant was only viewed in terms of durability and wear protection. Today we now know thicker is not better for current designs.
Hi,
the thick or thin issues will be around for ever it appears
Here are some viscosities for MY1941 American built cars
Gearbox
Winter - SAE30, 40, 50
Summer - SAE40, 50, 70 and SAE90 and SAE90EP gearlubes
Differentials
Over 0F - 80EP,90EP,140EP and 80Hypoid and 90Hypoid
Winter - 80EP and 80Hypoid
Sadly in these times diffs and gearboxes were often overhauled at around 50k
the thick or thin issues will be around for ever it appears
Here are some viscosities for MY1941 American built cars
Gearbox
Winter - SAE30, 40, 50
Summer - SAE40, 50, 70 and SAE90 and SAE90EP gearlubes
Differentials
Over 0F - 80EP,90EP,140EP and 80Hypoid and 90Hypoid
Winter - 80EP and 80Hypoid
Sadly in these times diffs and gearboxes were often overhauled at around 50k
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Wouldn't there be a difference in cold flow needs between rear axles and rear diff's?
I mean, in a stand-alone rear diff, with no axle tubes or anything, how far would the oil need to flow?
IMO gear set protection is #1 in those cases.
My MY00 Honda S2000 manual recommend the same diff oil as the MY08 manual, Honda never bothered to change it or look into it.
Currently using Amsoil SAE 190 in an aftermarket geared S2000 diff.
I mean, in a stand-alone rear diff, with no axle tubes or anything, how far would the oil need to flow?
IMO gear set protection is #1 in those cases.
My MY00 Honda S2000 manual recommend the same diff oil as the MY08 manual, Honda never bothered to change it or look into it.
Currently using Amsoil SAE 190 in an aftermarket geared S2000 diff.
Hi,
SpitfireS - Well much depends on diff design (size, gear sizes/patterns and etc) and location in/out of the airflow etc. Some diffs now only hold around a half litre of lubricant too
Flow of course means from around the casing etc as well as through the gear set
SpitfireS - Well much depends on diff design (size, gear sizes/patterns and etc) and location in/out of the airflow etc. Some diffs now only hold around a half litre of lubricant too
Flow of course means from around the casing etc as well as through the gear set
I published a similar test, albeit over a much shorter period of time, between a conventional 85W90, a synthetic 75W90 and a straight 90 with an unusual additive package. Rather than repeat it:
Axle Temp Test
Axle Temp Test
This is the S2000 diff housing, without the back cover (obviously
It holds (as INDYMAC said) about 800ml.
The oil passages are clearly visible, I've changed the brightness & contrast a little to make it easy to see.
Both passages allow oil "flow" towards the first pinion bearing.
The housing is downside-up in this picture.
When driving forward, the ring gear throws oil into the big opening (now at the bottom) and that oil lubricates and cools the first pinion bearing, some of that oil then makes it through the first bearing and lubricate the second bearing too but most will flow through the bottom passage, to be picked up by the ring.... etc.. etc..
That oil flow is also important, I agree.
Unless the oil is solid I think any oil will be thrown forward, the ring is spining at wheel revs.
Here is where I want my diff oil to do most of its work:
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Originally Posted By: Jim Allen
I published a similar test, albeit over a much shorter period of time, between a conventional 85W90, a synthetic 75W90 and a straight 90 with an unusual additive package. Rather than repeat it:
Axle Temp Test
Jim,
I read that test a while back and was intrigued how the LE607 could have a lower temperature than the synthetic. From your research do you think that the LE607 could go for extended drain periods in the differential such as 50k miles for towing? I have a Tundra that calls for SAE90 in the differential and that might be the ticket. BTW thanks for that other write up.
Ken
I published a similar test, albeit over a much shorter period of time, between a conventional 85W90, a synthetic 75W90 and a straight 90 with an unusual additive package. Rather than repeat it:
Axle Temp Test
Jim,
I read that test a while back and was intrigued how the LE607 could have a lower temperature than the synthetic. From your research do you think that the LE607 could go for extended drain periods in the differential such as 50k miles for towing? I have a Tundra that calls for SAE90 in the differential and that might be the ticket. BTW thanks for that other write up.
Ken
I definitely think it could... if it were still being manufactured. LE has replaced it with something else (Google Lubrication Engineers) and I don't know the new product. That oil is still in the truck, BTW, though it's probably only got about 20K on it by now.
I was intrigued with the results as well. It had to be the reduction of fricton. The difference between the oils was probably within a "margin of error" (though I tried to keep conditions as close to the same as I could) but that this straight 90 could equal a quality synthetic like Amsoil was surprising. It must be that whiz-bang Almasol additive they brag about.
I was intrigued with the results as well. It had to be the reduction of fricton. The difference between the oils was probably within a "margin of error" (though I tried to keep conditions as close to the same as I could) but that this straight 90 could equal a quality synthetic like Amsoil was surprising. It must be that whiz-bang Almasol additive they brag about.
I have LE 607 in my 2000 Tundra rear diff right now. In fact, I have it in all my vehicles (G35 and S2000). It is unique that it was one of the last remaining mineral SAE 90 GL5's. I suspect that it will go the distance, due to its design and intended purpose for industrial use. The industrial equipment they use this stuff in never shuts down and goes for extended drain intervals.
Since it has been discontinued, I planned to try LE 1605 (the 607 replacement). But alas, Johnny has provided me a vendor that still has some leftover 607. I was hoping that I could make a closeout/buyout offer to him, but he is treating it like gold! It reminds me of Jim Allen not wanting to part with any of his stash!
Since it has been discontinued, I planned to try LE 1605 (the 607 replacement). But alas, Johnny has provided me a vendor that still has some leftover 607. I was hoping that I could make a closeout/buyout offer to him, but he is treating it like gold! It reminds me of Jim Allen not wanting to part with any of his stash!
Originally Posted By: INDYMAC
I have LE 607 in my 2000 Tundra rear diff right now. In fact, I have it in all my vehicles (G35 and S2000). It is unique that it was one of the last remaining mineral SAE 90 GL5's. I suspect that it will go the distance, due to its design and intended purpose for industrial use. The industrial equipment they use this stuff in never shuts down and goes for extended drain intervals.
Since it has been discontinued, I planned to try LE 1605 (the 607 replacement). But alas, Johnny has provided me a vendor that still has some leftover 607. I was hoping that I could make a closeout/buyout offer to him, but he is treating it like gold! It reminds me of Jim Allen not wanting to part with any of his stash!
Indymac,
Do you notice any differences in your Tundra vs a multivis gear oil? If you don't mind, where do you purchase quarts of this stuff?
Thanks,
Ken
I have LE 607 in my 2000 Tundra rear diff right now. In fact, I have it in all my vehicles (G35 and S2000). It is unique that it was one of the last remaining mineral SAE 90 GL5's. I suspect that it will go the distance, due to its design and intended purpose for industrial use. The industrial equipment they use this stuff in never shuts down and goes for extended drain intervals.
Since it has been discontinued, I planned to try LE 1605 (the 607 replacement). But alas, Johnny has provided me a vendor that still has some leftover 607. I was hoping that I could make a closeout/buyout offer to him, but he is treating it like gold! It reminds me of Jim Allen not wanting to part with any of his stash!
Indymac,
Do you notice any differences in your Tundra vs a multivis gear oil? If you don't mind, where do you purchase quarts of this stuff?
Thanks,
Ken
Ken,
That's the site that Johnny sent me to. I think that's the same Mag-Hytec mod that Jim Allen did to his differential. There are very few sites that you can buy LE products by the quart too. The price is steep. It makes me wish I had bought a case (32qts) from LE when I first started using 607 for $234. Also, I wish I had used Auto-Rx in the diff before filling with 607 in my G35. There was gunk on the drain plug when I drained the old fluid. Will you notice a difference? Only if you have been experiencing gear noise (whining). You will notice a difference in physical characteristics versus a 75W90 though. I suspect that most people have never handled a SAE 90 before.
Jack
That's the site that Johnny sent me to. I think that's the same Mag-Hytec mod that Jim Allen did to his differential. There are very few sites that you can buy LE products by the quart too. The price is steep. It makes me wish I had bought a case (32qts) from LE when I first started using 607 for $234. Also, I wish I had used Auto-Rx in the diff before filling with 607 in my G35. There was gunk on the drain plug when I drained the old fluid. Will you notice a difference? Only if you have been experiencing gear noise (whining). You will notice a difference in physical characteristics versus a 75W90 though. I suspect that most people have never handled a SAE 90 before.
Jack
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I decided after reading and searching through a ton of posts on twinturbo.net to just go with the OEM spec dino 80W90 GL5,so I swung by Napa and grabbed 2 quarts of Sta Lube gear oil and installed it a couple of days ago. They all seemed to have the best results with dino OEM spec.
The question is "what are best results"? backed up with?
Its sad that some don't understand the difference in the typical weight range of a gear oil, especially those that are drivetrain engineeers.
Its also sad that #'s 1-7 were ignored when certain 'ends were failing, and certain suppliers/automakers simply jumped up the weight to 'fix' the failures. Have no faith in their validation. The real world puts it to shame over and over again.
Its sad that some don't understand the difference in the typical weight range of a gear oil, especially those that are drivetrain engineeers.
Its also sad that #'s 1-7 were ignored when certain 'ends were failing, and certain suppliers/automakers simply jumped up the weight to 'fix' the failures. Have no faith in their validation. The real world puts it to shame over and over again.
Originally Posted By: unDummy
Its sad that some don't understand the difference in the typical weight range of a gear oil, especially those that are drivetrain engineeers.
True, but everyone is so specialized today that the average joe drivetrain engineer relies on his lubricant specialist to do all that work for him. It seems that in the big OEM's it is very difficult to convince them to change what they have been using in the past unless there is some major benefit involved and in doing that you REALLY have to make your case with lots of test data and more data and then you need some additional data on top of that. If it a Japanese OE just triple the amount of data. Just don't give them copies or they will ignore you and have their kieretsu college buddies supplying (just by coincidence) that very same product in 3 weeks.
Its sad that some don't understand the difference in the typical weight range of a gear oil, especially those that are drivetrain engineeers.
True, but everyone is so specialized today that the average joe drivetrain engineer relies on his lubricant specialist to do all that work for him. It seems that in the big OEM's it is very difficult to convince them to change what they have been using in the past unless there is some major benefit involved and in doing that you REALLY have to make your case with lots of test data and more data and then you need some additional data on top of that. If it a Japanese OE just triple the amount of data. Just don't give them copies or they will ignore you and have their kieretsu college buddies supplying (just by coincidence) that very same product in 3 weeks.
Originally Posted By: PT1
It seems that in the big OEM's it is very difficult to convince them to change what they have been using in the past unless there is some major benefit involved and in doing that you REALLY have to make your case with lots of test data and more data and then you need some additional data on top of that. If it a Japanese OE just triple the amount of data.
Do you agree with me that when Honda recommended a single grade SAE 90 for the S2000 diff they really weren't thinking about a multiweight, like the popular 75W-90 gear oils?
And in 1998-1999 the SAE 90 range went as high as 24 cSt.
It's not easy to convince people a single grade isn't the same as a multiweight, even when the have the same "end" grade.
It seems that in the big OEM's it is very difficult to convince them to change what they have been using in the past unless there is some major benefit involved and in doing that you REALLY have to make your case with lots of test data and more data and then you need some additional data on top of that. If it a Japanese OE just triple the amount of data.
Do you agree with me that when Honda recommended a single grade SAE 90 for the S2000 diff they really weren't thinking about a multiweight, like the popular 75W-90 gear oils?
And in 1998-1999 the SAE 90 range went as high as 24 cSt.
It's not easy to convince people a single grade isn't the same as a multiweight, even when the have the same "end" grade.
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