Thinking of Mobil 1 Synthetic in my Dana/Spicer Motorhome Diff. w/32K Gross weight and Cummins 11 Liter engine. Why would one choose 90 weight over 140? Simply better when cold? Or am I missin' something? Locomotiveman
Heavy Truck Differential 75 W-90 or W-140?
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75W-140. What oil and transmission fluid are you using in your motorhome?
JOHNNY, Engine Oil in the Cummins M-11? Shell Rotella. Allison 4060 Tranny? Dunno. I bought the Motorhome used and I am doing a change-out of ALL the fluids. QUESTION: So why IS there different weights of synthetic oil for differentials? Locomotiveman
All depends on the application and load. Most passenger cars call for a 75W-90 because of the light duty application. Something carrying a heavier load, like and over the road truck, busses, your motorhome, heavy duty pick-ups, just about anything that carries a heavy load specs a 75W-140 in synthetics or a 80W-140 in a mineral based gear oil. The Mobil 1 75W-140 would be a good gear oil for your application.
I currently use Shell Spirax 75W-90 in my big truck rears. Never had a rear end problem using 75W-90. These trucks average 130k per year mostly staying in the South. Fluid get changed at 400k intervals. Here is a link for Dana Spicer lubricants.
http://www.roadranger.com/Roadranger/productssolutions/copyright/index.htm
Click on Lubrication Manual at lower right on the page
http://www.roadranger.com/Roadranger/productssolutions/copyright/index.htm
Click on Lubrication Manual at lower right on the page
THe pour point on a 85w140 dino gear oil is 0*F...I want to run it, but I am scared due to poor cold weather specs...but with a synthetic you can easily run the 75w140 in cold; I did it for many years.
HAvind said that, I am thinking of switching from 75w140 syn, to 80w90 dino for many reasons...it makes me feel better to hear someone say they ran 75w90 in big trucks with no issues.
HAvind said that, I am thinking of switching from 75w140 syn, to 80w90 dino for many reasons...it makes me feel better to hear someone say they ran 75w90 in big trucks with no issues.
Most of the newer axles spec SAE50 oil for them. What axle # is it?
If it's the same axle as a truck uses 80w90 will be fine. Trucks can weigh 80K or more so your 32K is a walk in the park for it.
I have pulled 132K with a single drive axle in a truck.
If it's the same axle as a truck uses 80w90 will be fine. Trucks can weigh 80K or more so your 32K is a walk in the park for it.
I have pulled 132K with a single drive axle in a truck.
Originally Posted By: Chris142
Most of the newer axles spec SAE50 oil for them. What axle # is it?
If it's the same axle as a truck uses 80w90 will be fine. Trucks can weigh 80K or more so your 32K is a walk in the park for it.
I have pulled 132K with a single drive axle in a truck.
SAE 50? really? I haven't heard of this. who is recommending it and in what type of vehicle? All of our new International trucks are coming through with syn 75w90 in the diffs and syn 50 in the tranny. just curious if its some thing I'm going to have to watch for.
Most of the newer axles spec SAE50 oil for them. What axle # is it?
If it's the same axle as a truck uses 80w90 will be fine. Trucks can weigh 80K or more so your 32K is a walk in the park for it.
I have pulled 132K with a single drive axle in a truck.
SAE 50? really? I haven't heard of this. who is recommending it and in what type of vehicle? All of our new International trucks are coming through with syn 75w90 in the diffs and syn 50 in the tranny. just curious if its some thing I'm going to have to watch for.
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Originally Posted By: slammds15
Originally Posted By: Chris142
Most of the newer axles spec SAE50 oil for them. What axle # is it?
If it's the same axle as a truck uses 80w90 will be fine. Trucks can weigh 80K or more so your 32K is a walk in the park for it.
I have pulled 132K with a single drive axle in a truck.
SAE 50? really? I haven't heard of this. who is recommending it and in what type of vehicle? All of our new International trucks are coming through with syn 75w90 in the diffs and syn 50 in the tranny. just curious if its some thing I'm going to have to watch for.
I last drove in 2002. We had a few Freightliners and a bunch of Petes they had the sticker on the rear end "Use Synthetic SAE50 oil only" right on it.
I don't know if they were Spicer or Eaton axles.
Originally Posted By: Chris142
Most of the newer axles spec SAE50 oil for them. What axle # is it?
If it's the same axle as a truck uses 80w90 will be fine. Trucks can weigh 80K or more so your 32K is a walk in the park for it.
I have pulled 132K with a single drive axle in a truck.
SAE 50? really? I haven't heard of this. who is recommending it and in what type of vehicle? All of our new International trucks are coming through with syn 75w90 in the diffs and syn 50 in the tranny. just curious if its some thing I'm going to have to watch for.
I last drove in 2002. We had a few Freightliners and a bunch of Petes they had the sticker on the rear end "Use Synthetic SAE50 oil only" right on it.
I don't know if they were Spicer or Eaton axles.
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Remember that big truck rear ends turn much slower than a light pick up. The ring gear is twice the diameter of the Dana 11.5 inch and the larger tires will also keep the gear from turning as much, thus the gears are turning half the speed of the 11.5 in a pick up. That will significantly reduce the temps that are reached in a class 8 rear end as opposed to a light pick up truck rear end. Not knowing the size of the OP rear end it would be best to follow the OEM recommended gear oil weight in his motorhome.
Originally Posted By: Dirtbikindad393
Remember that big truck rear ends turn much slower than a light pick up. The ring gear is twice the diameter of the Dana 11.5 inch and the larger tires will also keep the gear from turning as much, thus the gears are turning half the speed of the 11.5 in a pick up. That will significantly reduce the temps that are reached in a class 8 rear end as opposed to a light pick up truck rear end. Not knowing the size of the OP rear end it would be best to follow the OEM recommended gear oil weight in his motorhome.
+1 on all that.
Some folks on this thread seem to be assuming that since 90wt is appropriate for a pickup, then 140wt is appropriate for something bigger- and I don't really think that's the case. I'm not aware of any MODERN heavy truck that specifies a 140wt for the drive axles. I've been working on heavy trucks for well over a decade, and every one that I've seen has called for some type of 90wt (usually 80w90 dino gear oil or 75w90 synthetic), or the occasional SAE50 (it's a fuel mileage thing, I'm told).
At the Detroit Diesel dealership where I work, we occasionally have to service one of these differentials or replace one- and seeings how we get all makes and models of equipment in this shop, we may or may not have up-to-date service info on a given truck. So here's my rule of thumb for figuring out what oil to put in a differential when no info is available: First, look at (and around) the fill plug. When a differential on a heavy truck requires synthetic, there will generally be a tag on the fill plug (or a sticker beside it) telling you what type of oil it takes (of course, these can fall off). If there's no tag or sticker and it's an older vehicle (pre-2000 or so), then chances are it takes 80W90. Remove the plug, dip your finger in the oil and have a look. Most industrial synthetic gear oils are dyed (slightly) red. If it's reddish, add synthetic. If not... might be regular 80W90... might ought to find a manual and make sure- especially if it's a newer piece of equipment.
All that said, a 140W oil won't DAMAGE anything. But it will be of no added benefit, and you'll be wasting fuel. I know that most class 8 trucks get roughly 6mpg- so I'm guessing that your motorhome might get 8-9 if you're lucky. No sense burning more than necessary.
Remember that big truck rear ends turn much slower than a light pick up. The ring gear is twice the diameter of the Dana 11.5 inch and the larger tires will also keep the gear from turning as much, thus the gears are turning half the speed of the 11.5 in a pick up. That will significantly reduce the temps that are reached in a class 8 rear end as opposed to a light pick up truck rear end. Not knowing the size of the OP rear end it would be best to follow the OEM recommended gear oil weight in his motorhome.
+1 on all that.
Some folks on this thread seem to be assuming that since 90wt is appropriate for a pickup, then 140wt is appropriate for something bigger- and I don't really think that's the case. I'm not aware of any MODERN heavy truck that specifies a 140wt for the drive axles. I've been working on heavy trucks for well over a decade, and every one that I've seen has called for some type of 90wt (usually 80w90 dino gear oil or 75w90 synthetic), or the occasional SAE50 (it's a fuel mileage thing, I'm told).
At the Detroit Diesel dealership where I work, we occasionally have to service one of these differentials or replace one- and seeings how we get all makes and models of equipment in this shop, we may or may not have up-to-date service info on a given truck. So here's my rule of thumb for figuring out what oil to put in a differential when no info is available: First, look at (and around) the fill plug. When a differential on a heavy truck requires synthetic, there will generally be a tag on the fill plug (or a sticker beside it) telling you what type of oil it takes (of course, these can fall off). If there's no tag or sticker and it's an older vehicle (pre-2000 or so), then chances are it takes 80W90. Remove the plug, dip your finger in the oil and have a look. Most industrial synthetic gear oils are dyed (slightly) red. If it's reddish, add synthetic. If not... might be regular 80W90... might ought to find a manual and make sure- especially if it's a newer piece of equipment.
All that said, a 140W oil won't DAMAGE anything. But it will be of no added benefit, and you'll be wasting fuel. I know that most class 8 trucks get roughly 6mpg- so I'm guessing that your motorhome might get 8-9 if you're lucky. No sense burning more than necessary.
If there is no manual available you can't go wrong with a 75W-90 synthetic. Let us know what you do.
BTW, what year is this motorhome?
A Cummins M11 is an old friend of mine. Between 1996 and 2000, I replaced the head gasket, rod & main bearings, and cam bushings on many dozens of those engines (they had terrible problems with head gasket leaks at the time- leaking coolant directly into the oil, but a new-style head gasket mostly eliminated the problem). I got so that I can walk up to a pile of M11 parts and pretty much tell you where each bolt goes.
A Cummins M11 is an old friend of mine. Between 1996 and 2000, I replaced the head gasket, rod & main bearings, and cam bushings on many dozens of those engines (they had terrible problems with head gasket leaks at the time- leaking coolant directly into the oil, but a new-style head gasket mostly eliminated the problem). I got so that I can walk up to a pile of M11 parts and pretty much tell you where each bolt goes.
is SAE 50 on gear oil scale or motor oil scale?
When I worked in Las Vegas some International water trucks I worked on took 85W140 synthetic only. Oh and they had an oil filter on each diff too.
I have seen SAE50 specd for trannies, never for diffs.
Is that 50 a engine oil viscosity or a gear oil viscosity? If gear oil viscosity it would be a very very thin oil. If engine oil viscosity, why is gear oil rated on the engine oil viscosity chart?
Oops. I see someone else already asked the same question.
Is that 50 a engine oil viscosity or a gear oil viscosity? If gear oil viscosity it would be a very very thin oil. If engine oil viscosity, why is gear oil rated on the engine oil viscosity chart?
Oops. I see someone else already asked the same question.
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Originally Posted By: George7941
I have seen SAE50 specd for trannies, never for diffs.
I thought it was odd to. But the sticker was right on top of the pumpkin. I assumed it was referring to the axle and not the trans. I never slid under a trans to see what it took.
I have seen SAE50 specd for trannies, never for diffs.
I thought it was odd to. But the sticker was right on top of the pumpkin. I assumed it was referring to the axle and not the trans. I never slid under a trans to see what it took.
Originally Posted By: George7941
I have seen SAE50 specd for trannies, never for diffs.
Is that 50 a engine oil viscosity or a gear oil viscosity? If gear oil viscosity it would be a very very thin oil. If engine oil viscosity, why is gear oil rated on the engine oil viscosity chart?
Oops. I see someone else already asked the same question.
I looked it up, SAE 50 is on the engine oil scale so it is about a SAE 90 on the gear oil scale.
I have seen SAE50 specd for trannies, never for diffs.
Is that 50 a engine oil viscosity or a gear oil viscosity? If gear oil viscosity it would be a very very thin oil. If engine oil viscosity, why is gear oil rated on the engine oil viscosity chart?
Oops. I see someone else already asked the same question.
I looked it up, SAE 50 is on the engine oil scale so it is about a SAE 90 on the gear oil scale.
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