putting synthetic oil in a differential

[dailydriver]

Originally Posted By: Ducman
Interestingly the recommended oil in the USA for my vehicle is 75w-140 grade. I suspect due to availability.
As the vehicle was originally manufactured here in Australia and then exported to the USA, I would wager the factory fill was the Mobillube SHC ID 80w-140.


Monaro/GTO, or Commodore/G8??

 

[Ducman]

2006 HSV GTO (LS2 engine)

 

[Shannow]

Originally Posted By: Ducman
It is my understanding that the OEM(Dana BTR Australia) of the rear axle in my vehicle had done extensive testing on potential lubes for the application, with only one possible type and grade of lube found to be fit for service.

For my vehicle there was only one oil(Mobil SHC ID 80-140) which required 90-100 ml of Sturaco 7098 to be added for the rear axle(M80). This oil has been out of production for a number of years now.
The replacement oil on the market became Castrol SAF-XA 80w-140 by default. It had the maximum amount of Sturaco 7098 additive already included in the finished/bottled oil.
As is the tradition of Castrol, this oil has been renamed Syntrax 80w-140.

Interestingly the recommended oil in the USA for my vehicle is 75w-140 grade. I suspect due to availability.
As the vehicle was originally manufactured here in Australia and then exported to the USA, I would wager the factory fill was the Mobillube SHC ID 80w-140.


The SHC ID had the LSD additive in it, I used it in my Navara...my Mobil guy got the plain SHC by accident, and the clutches banged...the SHC ID didn't when he replaced it.

Am peeved that they ditched the product...RP 75W140 went black, and came out gluggy in 30,000km.

There's another complicator in the mix, which I find interesting.

Eaton have another "line haul" versus "vocational" for diff lubes.

Quote:
Line Haul (On-highway)• High mileage operation (over 60,000 miles [96,500 Km] per year).• On-highway or good to excellent concrete or asphalt.• More than 30 miles [48 Km] between starting and stopping.• 4x2, 6x2, 6x4 tractor/trailer combinations and straight trucks.• Check fluid levels and inspect for leaks at regular PM maintenance intervals, not to exceed 12,000 miles.

Vocational• Low mileage operation (under 60,000 miles [96,500 Km] per year).• Off-highway or areas of unstable or loose unimproved road surfaces.• Less than 30 miles [48 Km] between starting and stopping.• Heavy-Duty, off-road or specialized application type vehicles.• Check fluid levels and inspect for leaks every 50 hours.


The former, they go 75W90
The latter they go xW140

So the high speed gets a lower viscosity, while the more frequent starts/stops (impacts) gets the heavier lube.

 

[Olas]

I realise my diff is not the same style or type of diff the OP asked about, but the thread title doesn't differentiate, it only asks about synthetics in diffs.

Regardless, syn>conv.

 

[Shannow]

Here's the AGMA standard that we were taught to use back in the University days.

http://mach.jlu.edu.cn/jxcx/standars/AGMA-ANSI/AGMA 9005-E02-Industrial Gear Lubrication.pdf

It's typically for constant speed gear sets, but the applicability to multiple gearsets in the same box is assured by working out the worst case set in the box, and applying the lubricant to the whole box...it's that flexible.

So given the above mentioned Eaton recommendation(s), you can see that they are considering two different duty points.

Note the AGMA uses the ISO grade (KV at 40), then modifies that with viscosity index at operating temperature.

 

[Ducman]

Originally Posted By: Shannow
Originally Posted By: Ducman
It is my understanding that the OEM(Dana BTR Australia) of the rear axle in my vehicle had done extensive testing on potential lubes for the application, with only one possible type and grade of lube found to be fit for service.

For my vehicle there was only one oil(Mobil SHC ID 80-140) which required 90-100 ml of Sturaco 7098 to be added for the rear axle(M80). This oil has been out of production for a number of years now.
The replacement oil on the market became Castrol SAF-XA 80w-140 by default. It had the maximum amount of Sturaco 7098 additive already included in the finished/bottled oil.
As is the tradition of Castrol, this oil has been renamed Syntrax 80w-140.

Interestingly the recommended oil in the USA for my vehicle is 75w-140 grade. I suspect due to availability.
As the vehicle was originally manufactured here in Australia and then exported to the USA, I would wager the factory fill was the Mobillube SHC ID 80w-140.


The SHC ID had the LSD additive in it, I used it in my Navara...my Mobil guy got the plain SHC by accident, and the clutches banged...the SHC ID didn't when he replaced it.

Am peeved that they ditched the product...RP 75W140 went black, and came out gluggy in 30,000km.

There's another complicator in the mix, which I find interesting.

Eaton have another "line haul" versus "vocational" for diff lubes.

Quote:
Line Haul (On-highway)• High mileage operation (over 60,000 miles [96,500 Km] per year).• On-highway or good to excellent concrete or asphalt.• More than 30 miles [48 Km] between starting and stopping.• 4x2, 6x2, 6x4 tractor/trailer combinations and straight trucks.• Check fluid levels and inspect for leaks at regular PM maintenance intervals, not to exceed 12,000 miles.

Vocational• Low mileage operation (under 60,000 miles [96,500 Km] per year).• Off-highway or areas of unstable or loose unimproved road surfaces.• Less than 30 miles [48 Km] between starting and stopping.• Heavy-Duty, off-road or specialized application type vehicles.• Check fluid levels and inspect for leaks every 50 hours.


The former, they go 75W90
The latter they go xW140

So the high speed gets a lower viscosity, while the more frequent starts/stops (impacts) gets the heavier lube.


Interesting stuff Shannow.
Especially with regard to the recommended service life of the fluid.

The information I have to date regarding SHC ID doesn't mention anything about the additive. The only oils I've seen with it stated clearly no further additive was to be put in was the Castrol and Penrite?(I think). As they state the maximum treat rate was already added.

From memory like just about everybody else, Holden originally recommend putting the additive in "if diff chatter occurred". At some point I think I saw a TSB somewhere stating that a full bottle of additive needed to be added to the diff as a matter of course.
It was just before the new model with the ZF rear end, and they were having a lot of warranty trouble(mostly noise related) with the Dana BTR units. I knew 1 fellow who had 3 units replaced under warranty in his VZ ute.
With this in mind, at the first opportunity around the first 1000ks the dealer did a transmission and diff oil change for me(as the vehicle was under warranty) and the FF was dropped out and refilled. I had a bottle of additive in stock and that went in with the fill of SHC ID(dealer supplied) at the dealer with no questions asked.

Perhaps the SHC ID had a minimum amount of additive as a 1 stop shop with a view to more being added afterward as required?
The later default position for Castrol and Penrite was to have the full treatment regardless. I assume for simplicity and effectiveness.

The matter of viscosity is interesting.
Originally Castrol SAF-XA was a 75w-140 grade oil and was changed to the later 80w-140 grade.

Amsoil originally had a recommendation for their 75w-140 grade SG oil.
A number of years ago I had an interesting exchange with Amsoil over the matter and shared as much detailed background information as I had with them. I was not convinced their recommended grade was up to the task. Perhaps in north America but not throughout the USA?
I see in recent times Amsoil have revised their recommendation to state there's no longer a recommendation.
With 2 exceptions according to Amsoil.
1. Limited Slip additive must be used.
2. Synthetic oil must be used.
This aligns completely with my understanding in the application, so I assume they did some homework and made some changes on their end.

Regarding the internal speed of the gears in service (line-haul v vocational).
I believe in some applications it is vital to consider the manufacturers recommendations, as they've already done their durability testing and know the limitations of the assemblies/lube combination.
This potentially could pertain to the OP's question and in some cases all of us to some extent.

When I originally considered the 75w-140 grade, it wasn't until I had a very close look at the viscosity differences between a synthetic 75w-140 and a synthetic 80w-140 that I realized they may very well not be comparable in service.
Yet on the face of it, they could conceivably be interchangeable.
The reality may be different depending upon the application.

Clearly shock loading and cyclical loading comes into play as a factor as well.

 

[zeng]

Originally Posted By: Ducman
And then there are other manufacturers that exclusively call for synthetic.
For my vehicle there was only one oil(Mobil SHC ID 80-140) which required 90-100 ml of Sturaco 7098 to be added for the rear axle(M80). This oil has been out of production for a number of years now.
The replacement oil on the market became Castrol SAF-XA 80w-140 by default. It had the maximum amount of Sturaco 7098 additive already included in the finished/bottled oil.
As is the tradition of Castrol, this oil has been renamed Syntrax 80w-140.

Interestingly the recommended oil in the USA for my vehicle is 75w-140 grade. I suspect due to availability.
As the vehicle was originally manufactured here in Australia and then exported to the USA, I would wager the factory fill was the Mobillube SHC ID 80w-140.

Regarding the OP's question.
We have no background knowledge as to the specific application as Molakule duly points out above to another respondent.


Interesting points.

The synthetic 80W140 typically has a KV@40*C of 230 cSt, and would be classified as AGMA 5EP /ISO 220 gear oils.

Whereas a synthetic 75W140 is typically KV@40*C of 17X cSt , which is too thin for AGMA 5EP / ISO 220 (range from 198 to 242 cSt), and it's marginally thicker than a AGMA 4EP / ISO 150 (range from 135 to 165 cSt)

In a constant rotational speed industrial settings, this 75W140 of KV@40*C of 17X cSt, would be used where AGMA 4EP / ISO 150 is recommended, and NOT in applications where AGMA 5EP / ISO 220 is called for. This principle is more pertinent in variable rotational speed automotive settings, where thicker oil (irrespective of synthetics or minerals) is desperately NEEDED for components wear protection ....... every other things being equal.

JMHO

 

[dailydriver]

Is the Dana BTR diff a clutch plate, Torsen/worm gear, or cone clutch (Auburn like) type differential??

It is hard to tell from their site's explosion diagrams online as it will not let me increase the size of the images.

 

[Shannow]

Originally Posted By: Ducman
The information I have to date regarding SHC ID doesn't mention anything about the additive. The only oils I've seen with it stated clearly no further additive was to be put in was the Castrol and Penrite?(I think). As they state the maximum treat rate was already added.


Lifted from my 2001 South Pacific Product Guide

My mobil bloke brought in the former, and it chattered and banged, the latter worked perfectly.

 

[Shannow]

I think zeng's nailed it...

the 140, 110, 90 (i.e. 100C KV) isn't the issue, it's where it is in the operating range(s) that matter...thus the AGMA technique of specifying the KV40 (ISO) grade and the VII - note the requirement that they state, just like Cat T0-4 that in order to use it it has to be shear stable, both temporary and permanent.

 

[zeng]

Originally Posted By: Shannow
The SHC ID had the LSD additive in it, I used it in my Navara...my Mobil guy got the plain SHC by accident, and the clutches banged...the SHC ID didn't when he replaced it.

Am peeved that they ditched the product...RP 75W140 went black, and came out gluggy in 30,000km.

There's another complicator in the mix, which I find interesting.

Eaton have another "line haul" versus "vocational" for diff lubes.

Quote:
Line Haul (On-highway)• High mileage operation (over 60,000 miles [96,500 Km] per year).• On-highway or good to excellent concrete or asphalt.• More than 30 miles [48 Km] between starting and stopping.• 4x2, 6x2, 6x4 tractor/trailer combinations and straight trucks.• Check fluid levels and inspect for leaks at regular PM maintenance intervals, not to exceed 12,000 miles.

Vocational• Low mileage operation (under 60,000 miles [96,500 Km] per year).• Off-highway or areas of unstable or loose unimproved road surfaces.• Less than 30 miles [48 Km] between starting and stopping.• Heavy-Duty, off-road or specialized application type vehicles.• Check fluid levels and inspect for leaks every 50 hours.


The former, they go 75W90
The latter they go xW140

So the high speed gets a lower viscosity, while the more frequent starts/stops (impacts) gets the heavier lube.


The factory recommendation of 80W140 is KV@40*C 230 cSt.

The replacement RP 75W140 is typically KV@40*C 195 cSt.It appears to look just fine , could it be viscosity shearing under hypoid gear load that got you into trouble ?

Eaton/Dana recommends 75W90 for line haul requiring >96000 km per year. Looks like 80W140 should apply in our typical passenger/Eaton cars I suppose.

 

[Ducman]

Originally Posted By: zeng
Originally Posted By: Shannow
The SHC ID had the LSD additive in it, I used it in my Navara...my Mobil guy got the plain SHC by accident, and the clutches banged...the SHC ID didn't when he replaced it.

Am peeved that they ditched the product...RP 75W140 went black, and came out gluggy in 30,000km.

There's another complicator in the mix, which I find interesting.

Eaton have another "line haul" versus "vocational" for diff lubes.

Quote:
Line Haul (On-highway)• High mileage operation (over 60,000 miles [96,500 Km] per year).• On-highway or good to excellent concrete or asphalt.• More than 30 miles [48 Km] between starting and stopping.• 4x2, 6x2, 6x4 tractor/trailer combinations and straight trucks.• Check fluid levels and inspect for leaks at regular PM maintenance intervals, not to exceed 12,000 miles.

Vocational• Low mileage operation (under 60,000 miles [96,500 Km] per year).• Off-highway or areas of unstable or loose unimproved road surfaces.• Less than 30 miles [48 Km] between starting and stopping.• Heavy-Duty, off-road or specialized application type vehicles.• Check fluid levels and inspect for leaks every 50 hours.


The former, they go 75W90
The latter they go xW140

So the high speed gets a lower viscosity, while the more frequent starts/stops (impacts) gets the heavier lube.


The factory recommendation of 80W140 is KV@40*C 230 cSt.

The replacement RP 75W140 is typically KV@40*C 195 cSt.It appears to look just fine , could it be viscosity shearing under hypoid gear load that got you into trouble ?

Eaton/Dana recommends 75W90 for line haul requiring >96000 km per year. Looks like 80W140 should apply in our typical passenger/Eaton cars I suppose.


There's no reason not to use the thicker oil.
It also would be a better choice from the point of view of the manufacturer, especially in a "filled for life" limited slip unit that has a small oil volume.
It could almost be described as an over driven unit under some circumstances.

 

[artificialist]

75w90 is a perfect replacement for 80w90. Wherever I worked, 80w90 conventional and 75w90 synthetic would be stocked at the same time. Whenever we ran out of 80w90, we used 75w90 syn and never had a single problem.

We did the same thing for cars and trucks that used SAE90 GL-5.