I used to work as a Lab Tech at Auburn Gear, testing and evaluating their limited slip differentials. We had thermocouples installed on our test vehicles. We would test under extreme conditions until the temperature reached 250 degF. Philip.
Anyone Running a Diff Oil Temp Gauge?
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Good post, I was wondering this myself. While we're on the subject of diffs, my D35 rear diff on my Jeep makes a constant errrrrrrrr sound (not too loud) at speeds of 45mph and below...the noise is much less durings speeds above that on the highway which is more of a light shhhhhh sound. The only thing I had replaced in the rear diff were the carrier bearings at 50K and have been using synthetic 75W140 ever since(currently 102K miles on the OD). Any ideas?
I used to build towing and recovery equipment and still drive occasionally (just because I like the abuse). The two trucks that get the hottest gear oil temps are a 2001 T800 Kenworth and a 1990 T800 Kenworth. The older truck is a 1040 Rotator wrecker that weighs in at 53,000lbs unloaded and has a 450hp Series 60 and 46K Eaton Diffs. The newer truck is a 550 hp C-15 also with 46k Eatons, unloaded only 43,000. I've had 200 degrees in the new truck pulling mountain passes when loaded out past 120,000 gross. This truck normally runs 100-140 with average loads. The older truck runs about 25 degrees high in a similar situation since it's unloaded weight is higher.
My 2001 F350 (10.5 Sterling single tire)does not have a thermocouple yet, but it gets hot enough with synthetic 75w140 to bake the paint off the inspection cover.
The newest editions to Pete's Towing fleet all have 46k Eatons that are factory long life filled with synthetic 75w140. Anybody know who makes lube?
My 2001 F350 (10.5 Sterling single tire)does not have a thermocouple yet, but it gets hot enough with synthetic 75w140 to bake the paint off the inspection cover.
Hi,
sorry but I only have statistical data on heavy trucks (500hp DD DDEC4)
Col 1 is average, Col 2 is highest)
18 speed Gearbox: 86C - 100C Synthetic SAE50
Front diff 462P: 90C - 102C Synthetic 75w-90
Rear diff: 462P 94C - 102C Synthetic 75w-90
In my experience in this area a 75w-90 synthetic will run about 15-20C cooler than a 80w-140 mineral lubricant. Eaton have long recommended a 75w-90 synthetic for use in all ambient temperatures
Doug
sorry but I only have statistical data on heavy trucks (500hp DD DDEC4)
Col 1 is average, Col 2 is highest)
18 speed Gearbox: 86C - 100C Synthetic SAE50
Front diff 462P: 90C - 102C Synthetic 75w-90
Rear diff: 462P 94C - 102C Synthetic 75w-90
In my experience in this area a 75w-90 synthetic will run about 15-20C cooler than a 80w-140 mineral lubricant. Eaton have long recommended a 75w-90 synthetic for use in all ambient temperatures
Doug
If anyone is running a diff oil temp gauge, especially on a truck that works, i'd be interested to hear what sorts of temps you are getting, as well as details on the truck, oil used, etc. I just installed one in my trusty old '86 F-250HD 4x4 (4:10:1 Sterling). Too early to post any numer snow but I will soon.
Doug - what kind of weight are you toting to average 90c? In my experience that is quite warm, although we generally aren't allowed to run anywhere near as heavy as those in your neck of the woods.
I don't know the model number of the diffs on our newest trucks off hand, they are 46k pound 2 speed Eatons. They came factory filled with synthetic, and the book called for 75(or80)w-140. Maybe that could be mineral and the syb is 75w90, book didn't specify.
I have seen trans temps very similar to what you stated on average as well (again we generally don't gross more than 105K pounds). We run mostly RTLO 18spds with the factory label syn lube.
Patrick
I don't know the model number of the diffs on our newest trucks off hand, they are 46k pound 2 speed Eatons. They came factory filled with synthetic, and the book called for 75(or80)w-140. Maybe that could be mineral and the syb is 75w90, book didn't specify.
I have seen trans temps very similar to what you stated on average as well (again we generally don't gross more than 105K pounds). We run mostly RTLO 18spds with the factory label syn lube.
Patrick
Hi Patrick,
my trucks are rated at 68500kgs (170700lbs) but we are legal at 42500kgs(93500lbs)and are always loaded at that (truely!). We do no empty running at all!
All of my trucks are OEM speed limited to 100kmh (62mph) and spend a lot of time between 80 and 100kmh. They run 1650rpm at 100kmh (4.33 diffs)
The DS462Ps are rated at 46000lbs and I use RTLO 18918B boxes (with oil coolers)
In my operation we have a few long & steep climbs but about 80% of the running is flat to mild undulating terrain
We found that running synthetic SAE50 (instead of mineral SAE50 or GL1 SAE90) preserved "new shift" feel to way beyond 1.3 million kms regardless of the Driver's skills - or lack of)
If a Driver is caught making clutchless shifts they are fired without arguement!
We change the transmission/diff oils every 1m kms or at four years! We replace gearbox filters at 150k kms and our clutches generally last for 800k kms (500k miles) on average
Our operating ambient temperatures range from -10C to 42F+ and this could be experienced on the same day!
Doug
my trucks are rated at 68500kgs (170700lbs) but we are legal at 42500kgs(93500lbs)and are always loaded at that (truely!). We do no empty running at all!
All of my trucks are OEM speed limited to 100kmh (62mph) and spend a lot of time between 80 and 100kmh. They run 1650rpm at 100kmh (4.33 diffs)
The DS462Ps are rated at 46000lbs and I use RTLO 18918B boxes (with oil coolers)
In my operation we have a few long & steep climbs but about 80% of the running is flat to mild undulating terrain
We found that running synthetic SAE50 (instead of mineral SAE50 or GL1 SAE90) preserved "new shift" feel to way beyond 1.3 million kms regardless of the Driver's skills - or lack of)
If a Driver is caught making clutchless shifts they are fired without arguement!
We change the transmission/diff oils every 1m kms or at four years! We replace gearbox filters at 150k kms and our clutches generally last for 800k kms (500k miles) on average
Our operating ambient temperatures range from -10C to 42F+ and this could be experienced on the same day!
Doug
Doug,
it sounds like you have quite a similar idea to the owner at Pete's. We also do not allow clutchless shifts, unless it's me. Although the RTLO's seem to shift quite nicley with the clutch. But I learned to drive on a notchy old 5&4 (steer with knee and shift with both hands).
In the towing industry here is the states we don't put a lot of miles on our trucks, but many hours. (79 W900 1040SDU with 538K miles, lost track of hours - 10K+). It's not uncommon to have a truck running for 12-15 hours and only put 200 miles on it in a day.
That 79 W900 has had many diff failures. It only has 40K rears and runs mineral lube. It seems that this is more related to the drivers lack of ability than a lube related problem. Usally broken axles. And this truck interestly see some of lower lube temps (80-125F average).
We have had excellant results with the DSP462/3P with either 4.11/5.60 or the 4.33/5.90.
We usally have a mechanical failure before the synthetic lube really needs to be changed (even with mostly senor drivers, these are high maintence trucks - very sever duty on/off road). I am thinking of trying a differant brand lube for the RTLO's, the factory fill shifts poorly, IMO, cold in all of our trucks.
What brand oil's are you running in the diffs/trans? The factory fill is claimed to be a PAO, and I have not complaints about the oil or component life - I just want the trans to shift nicer cold. What good is having your cake if you can't eat it?
Patrick
it sounds like you have quite a similar idea to the owner at Pete's. We also do not allow clutchless shifts, unless it's me. Although the RTLO's seem to shift quite nicley with the clutch. But I learned to drive on a notchy old 5&4 (steer with knee and shift with both hands).
In the towing industry here is the states we don't put a lot of miles on our trucks, but many hours. (79 W900 1040SDU with 538K miles, lost track of hours - 10K+). It's not uncommon to have a truck running for 12-15 hours and only put 200 miles on it in a day.
That 79 W900 has had many diff failures. It only has 40K rears and runs mineral lube. It seems that this is more related to the drivers lack of ability than a lube related problem. Usally broken axles. And this truck interestly see some of lower lube temps (80-125F average).
We have had excellant results with the DSP462/3P with either 4.11/5.60 or the 4.33/5.90.
We usally have a mechanical failure before the synthetic lube really needs to be changed (even with mostly senor drivers, these are high maintence trucks - very sever duty on/off road). I am thinking of trying a differant brand lube for the RTLO's, the factory fill shifts poorly, IMO, cold in all of our trucks.
What brand oil's are you running in the diffs/trans? The factory fill is claimed to be a PAO, and I have not complaints about the oil or component life - I just want the trans to shift nicer cold. What good is having your cake if you can't eat it?
Patrick
Hi Patrick,
for many years I used Shell then Castrol's synthetic oils
We then tried Mobil 1 and the results have been identical
The gearbox synthetic is great at improving cold oil shifting
I still have a "soft spot" for Castrol's gear lubricants
Doug
for many years I used Shell then Castrol's synthetic oils
We then tried Mobil 1 and the results have been identical
The gearbox synthetic is great at improving cold oil shifting
I still have a "soft spot" for Castrol's gear lubricants
Doug
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