^^^Yes, at least Eaton/Detroit gives you some info.
Quaife flat out REFUSES to give even a hint of their bias ratios.
Quaife flat out REFUSES to give even a hint of their bias ratios.
Eaton Gear Oil Recommendations for the Truetrac
- Thread starter Brian Barnhart
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Originally Posted By: dailydriver
What is the bias ratio of the Truetracs, 2:1, or even less than that?
Does it differ according to application (vehicle)??
I've had a tough time trying to find out bias ratios for specific Easton truetrac differentials. They are different, depending upon application. I remember reading in one of the off-road magazines that the Dana 60 truetrac was a 3:1 bias ratio, which is quite aggressive, but I haven't been able to confirm. I do know that it works very well in front of my F-250 Dana 60, so glad I didn't go with a locker up front, really no need to with the front truetrac and also provides a relatively smooth steering feel when engaged.
The smaller differentials such as GM 8.5, Ford 8.8 all have lower bias ratios from what I understand
Ford 10.5, GM 11.5, Ram 11.5 all should be in the 3.5:1 range would be my guess.
What is the bias ratio of the Truetracs, 2:1, or even less than that?
Does it differ according to application (vehicle)??
I've had a tough time trying to find out bias ratios for specific Easton truetrac differentials. They are different, depending upon application. I remember reading in one of the off-road magazines that the Dana 60 truetrac was a 3:1 bias ratio, which is quite aggressive, but I haven't been able to confirm. I do know that it works very well in front of my F-250 Dana 60, so glad I didn't go with a locker up front, really no need to with the front truetrac and also provides a relatively smooth steering feel when engaged.
The smaller differentials such as GM 8.5, Ford 8.8 all have lower bias ratios from what I understand
Ford 10.5, GM 11.5, Ram 11.5 all should be in the 3.5:1 range would be my guess.
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Powerstroke, what type of driving does your F250 see? I've always liked the idea of sticking a Truetrac in my front but since my typical 4wd use is on-road during winter storms I am concerned it would be too much.
This is an interesting discussion! I have TrueTracs in the front and rear of my 4Runner but honestly never stopped to consider if it could need something special to operate properly.
Looking at Eaton's website it looks like they have updated their recommendations to "allow" synthetics but still discourage oils with friction modifiers. I see that Mola has suggest Mobil Delvac Synth as a possible option here. Any other synthetics fit this bill? Anything from Amsoil?
Looking at Eaton's website it looks like they have updated their recommendations to "allow" synthetics but still discourage oils with friction modifiers. I see that Mola has suggest Mobil Delvac Synth as a possible option here. Any other synthetics fit this bill? Anything from Amsoil?
I am about to install a TrueTrac this weekend. I am keeping the same ring and pinion gear ratio. After reading this thread, I decided to use Redline 75W-140NS gear oil without any friction modifers. I will let you know how it works in my Tahoe daily driver.
Installation went well without any issues. I have found the unit to be very smooth in operation. I have not experienced any binding, clunking, nor other unusual sounds or operation. Both the unit and the Redline 75W-140 NS appear to be working as expected.
2011 GMC 2500 Dmax 4X4 and 2013 1500 5.3 max towing 4x4. Do these 2 trucks need LS type GL-5 fluids?
At 65K miles the front diff fluid looked like mud on the 1500, would 75w140 fix that?
Mobil has a LS type in that grade, likely the Ford factory fill where specified.
At 65K miles the front diff fluid looked like mud on the 1500, would 75w140 fix that?
Mobil has a LS type in that grade, likely the Ford factory fill where specified.
I doubt it. Do you tow in 4WD? Did you get water in the diff? Whats the recommended OCI?
FWIW when I drained the factory 90 weight fill in my wife's '14 Explorer rear dif it looked VERY good, almost new. Not sure if it was factory dino 80w90 or synth 75w90. Likewise, the factory 75w140 factory fill in my '11 F150 rear looked basically like new when drained at 82k miles when I swapped a posi in last week.
FWIW when I drained the factory 90 weight fill in my wife's '14 Explorer rear dif it looked VERY good, almost new. Not sure if it was factory dino 80w90 or synth 75w90. Likewise, the factory 75w140 factory fill in my '11 F150 rear looked basically like new when drained at 82k miles when I swapped a posi in last week.
The 2500 weighs about 7,500 lbs empty, not towing, but climbing and descending grades up to 14% daily.
I'll go up in 4x4, but not downhill especially on the exhaust brake,
because if the front tires lock up on ice, there is no way to steer the vehicle.
I did both ends and the transfer case on both vehicles just over 100k kms.
The diff fluid on the 2500 was as expected, but I should have done the transfer case at half time, or about 50k kms.
The FF is Dexron VI, which seems light to me. I used up the last of my Petro-Canada Dura-Drive instead, 1.5L.
On the 1500, the rear diff, no 3/8 drive drain plug so I had to syphon the fluid out, looked ok, as did the transfer case fluid.
But the front diff was a disaster.
Investigating the various GL-5 lubes reveals a large discrepancy from one brand to the next.
For example, if the Mobil 75w140 was any thinner, it would be a thick 75w110.
(SAE GL 110 is a relatively new grade. I'm surprised that 75W110 and 80w110s are not commonplace, especially for commercial transportation looking for fuel economy over the popular GL 140s.)
If Pet-Can's 75w90 was much thicker, it would be a thin 75w110, and so on.
And, if gear lubes are anything like engine oil, they lose their W rating over time and service.
I think the chart for gear oil grades is SAE J306.
SAE GL 80W is good down to -26C, not good enough. I need -35C or very close to it.
Synthetics are typically more forgiving as the temperature drops out of grade, and should stay fluid/colder than conventional.
I'm not concerned about getting the last tenth % of fuel economy, and looking at "thin" synthetic 80w140s for a new "go to" grade.
Any thoughts?
I'll go up in 4x4, but not downhill especially on the exhaust brake,
because if the front tires lock up on ice, there is no way to steer the vehicle.
I did both ends and the transfer case on both vehicles just over 100k kms.
The diff fluid on the 2500 was as expected, but I should have done the transfer case at half time, or about 50k kms.
The FF is Dexron VI, which seems light to me. I used up the last of my Petro-Canada Dura-Drive instead, 1.5L.
On the 1500, the rear diff, no 3/8 drive drain plug so I had to syphon the fluid out, looked ok, as did the transfer case fluid.
But the front diff was a disaster.
Investigating the various GL-5 lubes reveals a large discrepancy from one brand to the next.
For example, if the Mobil 75w140 was any thinner, it would be a thick 75w110.
(SAE GL 110 is a relatively new grade. I'm surprised that 75W110 and 80w110s are not commonplace, especially for commercial transportation looking for fuel economy over the popular GL 140s.)
If Pet-Can's 75w90 was much thicker, it would be a thin 75w110, and so on.
And, if gear lubes are anything like engine oil, they lose their W rating over time and service.
I think the chart for gear oil grades is SAE J306.
SAE GL 80W is good down to -26C, not good enough. I need -35C or very close to it.
Synthetics are typically more forgiving as the temperature drops out of grade, and should stay fluid/colder than conventional.
I'm not concerned about getting the last tenth % of fuel economy, and looking at "thin" synthetic 80w140s for a new "go to" grade.
Any thoughts?
Originally Posted By: userfriendly
At 65K miles the front diff fluid looked like mud on the 1500, would 75w140 fix that?
Yep, you need a thicker oil with higher KV@40*C ... but 75W140 shears much more than a 75W90.
Quote:
On the 1500 .....SAE GL 80W is good down to -26C, not good enough. I need -35C or very close to it.
I'm not concerned about getting the last tenth % of fuel economy, and looking at "thin" synthetic 80w140s for a new "go to" grade.Any thoughts?
You need a 75Wyyy at -35C..... and yes I would consider grabbing a 80W140 with the lowest possible pour point.
At 65K miles the front diff fluid looked like mud on the 1500, would 75w140 fix that?
Yep, you need a thicker oil with higher KV@40*C ... but 75W140 shears much more than a 75W90.
Quote:
On the 1500 .....SAE GL 80W is good down to -26C, not good enough. I need -35C or very close to it.
I'm not concerned about getting the last tenth % of fuel economy, and looking at "thin" synthetic 80w140s for a new "go to" grade.Any thoughts?
You need a 75Wyyy at -35C..... and yes I would consider grabbing a 80W140 with the lowest possible pour point.
It took me a few hours of poking around to solve the $29USD/QT grape juice mystery #GM9986115.
It turns out to be a packaging code and not a stand alone lubricant specification. GM9986115 is another way of stating: GL-5, J2360.
www.eaton.com has their own lubricant portfolio.
The issue with the GMC 1500 front diff is the 80W90 conventional GL-5 non-synthetic fluid.
The rear diff has 75w90, as does both front and rear in the 2500.
After 3 winters, 65K miles and approximately 1700 hours, the fluid would have lost it's W rating altogether.
Now add the contaminant load.
So why did GM put a non synthetic lubricant of insufficient W grade in a vehicle that may see -40C/F?
Near as I could tell from reading other forums, it doesn't matter much to the diff whether an LS type fluid is used or not.
Chevron states in their literature that the LS additive does not affect the load carrying capacity of the bearings, or compromise gear wear.
In other words, LS type gear lubes may be used in conventional differentials with no adverse effect.
It turns out to be a packaging code and not a stand alone lubricant specification. GM9986115 is another way of stating: GL-5, J2360.
www.eaton.com has their own lubricant portfolio.
The issue with the GMC 1500 front diff is the 80W90 conventional GL-5 non-synthetic fluid.
The rear diff has 75w90, as does both front and rear in the 2500.
After 3 winters, 65K miles and approximately 1700 hours, the fluid would have lost it's W rating altogether.
Now add the contaminant load.
So why did GM put a non synthetic lubricant of insufficient W grade in a vehicle that may see -40C/F?
Near as I could tell from reading other forums, it doesn't matter much to the diff whether an LS type fluid is used or not.
Chevron states in their literature that the LS additive does not affect the load carrying capacity of the bearings, or compromise gear wear.
In other words, LS type gear lubes may be used in conventional differentials with no adverse effect.
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Originally Posted By: JZiggy
Looking at Eaton's website it looks like they have updated their recommendations to "allow" synthetics but still discourage oils with friction modifiers. I see that Mola has suggest Mobil Delvac Synth as a possible option here. Any other synthetics fit this bill? Anything from Amsoil?
I just caught this looking back through the thread so went digging. Not sure if it has been updated again, but it looks like more than just allowing, it looks like Eaton has changed their tune to anything GL5 is good, less additives are better, but use whatever your manufacturer recommends. I'm personally much happier to see this type of answer than a blanket one-size-fits-all type of answer that led a lot of people on hunts for hard-to-find fluid.
Quote:
Detroit Truetrac®
High quality mineral or synthetic gear lubes are
required for use in Detroit Truetrac differentials.
Regardless of the lube type, always use a GL5 rated
lube with the least amount of friction modifier. Mineral
lubes lacking friction modifiers (limited-slip additives)
were historically recommended for all Truetrac
applications because friction modifiers can slightly
reduce the bias ratio (limited-slip aggressiveness) of
Truetrac differentials. However, to address the
continually increasing power outputs of modern
powertrains, many vehicle manufacturers have
switched to synthetic lubricants as a counter measure
for increased axle temperatures and prolonged service
intervals. In general, consult the vehicle owner's
manual for the manufacturer's recommendations for
lubrication type, weight and fill volume. This will ensure
lube compatibility with the seal materials and bearings
used in the axle. Eaton Performance technical support
is available for any concerns in lube selection.
Adam
Looking at Eaton's website it looks like they have updated their recommendations to "allow" synthetics but still discourage oils with friction modifiers. I see that Mola has suggest Mobil Delvac Synth as a possible option here. Any other synthetics fit this bill? Anything from Amsoil?
I just caught this looking back through the thread so went digging. Not sure if it has been updated again, but it looks like more than just allowing, it looks like Eaton has changed their tune to anything GL5 is good, less additives are better, but use whatever your manufacturer recommends. I'm personally much happier to see this type of answer than a blanket one-size-fits-all type of answer that led a lot of people on hunts for hard-to-find fluid.
Quote:
Detroit Truetrac®
High quality mineral or synthetic gear lubes are
required for use in Detroit Truetrac differentials.
Regardless of the lube type, always use a GL5 rated
lube with the least amount of friction modifier. Mineral
lubes lacking friction modifiers (limited-slip additives)
were historically recommended for all Truetrac
applications because friction modifiers can slightly
reduce the bias ratio (limited-slip aggressiveness) of
Truetrac differentials. However, to address the
continually increasing power outputs of modern
powertrains, many vehicle manufacturers have
switched to synthetic lubricants as a counter measure
for increased axle temperatures and prolonged service
intervals. In general, consult the vehicle owner's
manual for the manufacturer's recommendations for
lubrication type, weight and fill volume. This will ensure
lube compatibility with the seal materials and bearings
used in the axle. Eaton Performance technical support
is available for any concerns in lube selection.
Adam
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When researching fluid to use with the Eaton Truetrac, I had this same exact question. Forgive me if I missed the perfect answer (there are a lot of responses on this subject), but after reading through many forum entires on this site and others on this same issue, I didn't really find a satisfying answer.
I did some non-exhaustive and informal research on different gear oils. I found that most of the conventional oils contain a friction modifier, whether they advertise this or not. For some store brands, I was unable to determine if they contained friction modifier or not. Since much of what I read being recommended on this and other forums was synthetic, and Eaton recommends against the use of synthetics for this product, and I could not find a conventional oil without friction modifier in it, I contacted Eaton directly. I used Eaton Performance Products tech support number at 800-328-3850.
Confirming their recommendations and adding a bit more information, the Eaton performance technician pointed me towards 'Shell Spirax HD', and said Eaton had no recommendation or preference regarding oil weight (80W-90, 85W-140, etc.). He went on to say that he had heard of good results with Lucas Heavy Duty Gear Oil, but recommended against using anything from Valvoline or Napa. It is interesting to note that Lucas Oil confirmed to me that the mentioned product does have friction modifier in it. The Shell Spirax HD product can be hard to find, except from a dealer or on-line. There are also several products using 'Spirax' in the name, so be careful when searching and ordering.
We also agreed that the only issue here is that synthetics and friction modifiers increase the "slipperiness" of the oil, by design, and that the unit needs some friction for top performance. That is to say that a proper synthetic gear oil or proper gear oil with friction modifier in it isn't going to damage the unit, and may be a good choice for your application, but they will (may?) reduce the bias ratio or aggressiveness of the unit.
As for me, I ordered Shell 5921212091 Spirax HD Gear Oil 85W-140 for use in my truck from Jet.com, and noticed that it is also available from TrueValue.com.
I did some non-exhaustive and informal research on different gear oils. I found that most of the conventional oils contain a friction modifier, whether they advertise this or not. For some store brands, I was unable to determine if they contained friction modifier or not. Since much of what I read being recommended on this and other forums was synthetic, and Eaton recommends against the use of synthetics for this product, and I could not find a conventional oil without friction modifier in it, I contacted Eaton directly. I used Eaton Performance Products tech support number at 800-328-3850.
Confirming their recommendations and adding a bit more information, the Eaton performance technician pointed me towards 'Shell Spirax HD', and said Eaton had no recommendation or preference regarding oil weight (80W-90, 85W-140, etc.). He went on to say that he had heard of good results with Lucas Heavy Duty Gear Oil, but recommended against using anything from Valvoline or Napa. It is interesting to note that Lucas Oil confirmed to me that the mentioned product does have friction modifier in it. The Shell Spirax HD product can be hard to find, except from a dealer or on-line. There are also several products using 'Spirax' in the name, so be careful when searching and ordering.
We also agreed that the only issue here is that synthetics and friction modifiers increase the "slipperiness" of the oil, by design, and that the unit needs some friction for top performance. That is to say that a proper synthetic gear oil or proper gear oil with friction modifier in it isn't going to damage the unit, and may be a good choice for your application, but they will (may?) reduce the bias ratio or aggressiveness of the unit.
As for me, I ordered Shell 5921212091 Spirax HD Gear Oil 85W-140 for use in my truck from Jet.com, and noticed that it is also available from TrueValue.com.
4WD
$50 site donor 2024
Are those in the same league ? I'd compare to Delvac 1 gear oil - serious builder approvals ...
4WD
$50 site donor 2024
The question to me is why - GM and AAM and others don't seem to agree on Dino gear oil for Eaton's sake. Eaton says thier kit does not really add heat. I never replaced a rear end in decades over the locker. Ring, pinion, spiders, bearings,, yes - a Shell quick change slipped Dino in on me - DOA a few thou past warranty- full rear goes in out of my pocket - were it not for the gear oil stink - would of said it was hydraulic fluid - it broke down that bad.
Schaeffer went in the new one. This site alone is loaded with folks running synthetic in those Eaton's for years - no way I'll change that.
The LS issue to me is a matter of dosing - I use M1 LS in front and used to run it in both - but in the last couple years decided Delvac was stronger and did not contain a Posi Trac type FM ...
Schaeffer went in the new one. This site alone is loaded with folks running synthetic in those Eaton's for years - no way I'll change that.
The LS issue to me is a matter of dosing - I use M1 LS in front and used to run it in both - but in the last couple years decided Delvac was stronger and did not contain a Posi Trac type FM ...
4WD
$50 site donor 2024
FYI - it's getting renamed Delvac 1 gear lubricant ...
Oh, I just realized this is an old thread when I saw MolaKule comment on Delvac ...
Oh, I just realized this is an old thread when I saw MolaKule comment on Delvac ...
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