2nd Gen Non-Engine/Transmission Which weight synthetic gear oil??

[Coyote556]

hello, this is my first post and i am a new member to tdr. i would like to say this is a great site. now, i am getting ready to change the rear end oil in a truck i just bought. it has 30k on it and it is a 2002. i will be doing some occassional towing but nothing too heavy. i was thinking about going with amsoil in the rear end but i cant decide what weight. i live in missouri and it gets hot here in the summer but also very cold in the winter. i apprecate any help and i am happy to be a new tdr member.

 

[RJOL]

If you're only towing occasionally, and you live in a cold Winter climate, I'd recommend the 75/90 weight.



Here is another option for synthetic differential oil:



http://www.coximport.com/royalpurple/apps.html



No extra additives or friction modifiers required for use in limited slip differentials.



Have fun...

 

[Coyote556]

do you think the royal purple is better than the amsoil??

 

[RJOL]

Don't know anything about Amsoil, and don't care to start an "OIL WAR" here...



There are a lot of TDR members using Royal Purple. It's what I use...

 

[krs]

Look in your owner's manual for a notice recommending a 75-140 wt synthetic if the truck is used for (heavy) towing. It's there.



I don't think it really matters much which synthetic is used but I think it's interesting that the factory makes the recommendation. Why, if there's any question about the truck usage, don't they give a factory fill of a multigrade synthetic? It couldn't be that saving the cost of the stuff is more important than the longevity of their trucks... ... ... could it?



-I believe in Santa Claus, don't you?

 

[illflem]

The Dodge manual doesn't state it but Dana says Delo RPM 85w-140 is the first non-synthetic approved for heavy loads and extended drain intervals in their differentials. I pay $28 for a 5 gallon tub...

http://library.cbest.chevron.com/lu...71a5fe83e81c311c88256628007d8eb1?OpenDocument

 

[mcoleman]

Welcome to the TDR. I use the Mobil 1 Synthetic lube available at Oreilly's. What part of MO are you from? North or South. There are a few of us down here in the Southwestern area.

 

[plongson]

Royal Purple

I changed from factory lube to Royal Purple mainly to reduce the differential temp. I also installed a Mag-Hytec. My initial results are about 20 degrees cooler on average, but this has been just around town. All readings were taken with a Raytec infrared spot radiometer set at e=95%. The real test comes this week when I pull about 17k GCVR several hundred miles. I would see 213 degrees at the pinion area before with the factory lube.

 

[Greystoke]

I have some Amsoil...

I have 20 quarts of Amsoil Series 2000 75w90 I'm not gonna use. Make me an offer for it...

 

[Coyote556]

i am from central missouri. i guess my delema is 75w-90 vs. 75w-140. i cant seem to make up my mind. i will be driving this thing empty more than loaded, but when it is loaded, i dont want to damage any thing. thanks for all the help thus far.

 

[JJW_ND]

75w90 ALL THE WAY

I have ran 75W90 for over 200K now. Sampled every 40 - 60K. I pulled very heavy, and for up to 1000 miles straight through loaded..... summer and winter.



I believe the 2003 trucks come with and spec 75W90. Most OTR tractor trailers run with 75W90.



Better fuel ecomony with 75W90 without giving up any protection. But you still have to change it depending on how hard you use your truck.



Run a good full synthetic 75W90. Sample or change at 50K. I found heavy towing would get the TAN value in the change oil range after 40K. Running empty should go indeffinetly.



If you have a LSD, try just the oil first. Then add LSD additive in very small anounts (2 oz) until the chatter goes away. Many need none, I need two 6 oz bottles.







jjw

ND

 

[John]

I've tried Red Line 75W-140NS, Amsoil Series 2000 75W-90 as well as Amsoil Series 2000 75W-140 gear oil in my Dana 70 differential.



As I found absolutely NO difference in fuel economy between the different synthetic gear lubricants, I decided to stay with the Amsoil Series 2000 75W-140 in both (front and rear) differentials.



Keep in mind I live in a rather temperate area... Western Washington State.

 

[klenger]

I think that the 75W1450 would only be a problem in very cold climates where the ring gear would tend to cut a slice through the fluid when cold and maybe not provide good lubrication. If yoiu are using synthetic, it still has a very low pour point compared to mineral oils. I'd say go for the 75W140. I used it when I lived in Denver with zero degree temps with no probems.

 

[krs]

"The Dodge manual doesn't state it but Dana says Delo RPM 85w-140 is the first non-synthetic approved for heavy loads and extended drain intervals in their differentials. I pay $28 for a 5 gallon tub... "



That's an interesting point, Bill, since the DC manual for the 2001 model year does state on page 171 that " for all trailer towing or heavy duty applications it is strongly recommended that the factory fill rear axle lubricant be replaced with an SAE 75W-140 synthetic gear lubricant. Mopar Synthetic Gear Lubricant is of this type".



Now I'm sure that the 2001 DC manual predates the information supplied for the Delo lube approved by Dana which carries an 2003 publication date. What was DC thinking to presume an expertise beyond that of the maker of the axle set?



(edit ubb)

 

[illflem]

Originally posted by KRS



Now I'm sure that the 2001 DC manual predates the information supplied for the Delo lube approved by Dana which carries an 2003 publication date. What was DC thinking to presume an expertise beyond that of the maker of the axle set?

I don't expect DC to keep up with advancements in lube technology, that's up to the end user. Lubes have been improving at a rapid rate and the manual's service intervals and types, especially for older rigs, shouldn't be considered gospel.

Don't expect Cummins to retro test older engines for use of new technology lubes, too expendsive. This is why it's a wise move to use oil analysis to basically do the testing yourself. You don't replace your tires when they have 90% of the tread left, why dump your oil when it has 90% of it's life left?

You can tell when your tires are worn by looking at them, looking at your oil tells you absolutely nothing, you must use analysis to know how long it lasts.

 

[C Schomer]

I think 75w90 is very minimal for towing. I used Ams 2k 75w90 for 13k miles and developed ring and pinion noises. I switched to RP 75w90 and the noises went away after a month. I did analysis on the RP at 10k and additives were depleted but looked like new. Went to RP 75w140 for 10k and it did good but not great. I now went to RP 85w140 after learning, it is MUCH more viscous then the 75w140. I don't tow heavy but run HARD. 80-85 mph westbound with wind on I80 thru Wy. Craig

 

[Coyote556]

I guess my only fear with 75w140 is that on those cold days, it will take too long for the lube to get to the pinoin bearing??

 

[C Schomer]

It should be fine with the 75w at the low end. The ringgear throws oil right at the pinion brgs. I've just had really sour luck with 75w90s! Maybe it's OK for others. Craig

 

[krs]

"I don't expect DC to keep up with advancements in lube technology"



No, neither would I. Yet DC recommends the use of a synthetic prior to Dana having found one which THEY found to warrant their approval. That was my point - it seems presumptuous at least and dangerous at worst for DC to sanction the use of a lubricant which may not adequately meet the axle manufacturer's requirement(s).

 

[Coyote556]

KRS,



does this mean you would not recomend synthetic in your rear end? thanks