Red Line or Royal Purple in Dodge 2500 Diffs?

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Strjock81

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I am considering these two oils to put in my front and rear differentials on my next swap. I am going to leave it in until 100K (55K miles). (Dodge wants it changed with full syn every 15K if you tow. and specs either 75w-90 or 75w-140 depending on application)

I just wanted to know if anyone had specific problems with either oil, and what they were. Since this truck is nearly always hooked to a 24' livestock trailer, I am going to go 75w-140. I would like to use Schaeffer's Syn, but don't want to buy a 5 gallon bucket of it, and I wouldn't have enough left over to properly service any of the tractors anyways. Also, the AAM Axles used in the newer Dodge trucks do not require the friction modifying additive for lockup, but does the additive have any effect, good or bad, on gear wear? Red Line and Royal Purple both blend it into their oils, but RL offers the same oil without it. Thanks.
 
I always used Red Line in the Dodge farm pickups (both 1500 and 2500), but they were the Dana axles. Worked very well; no complaints. I could never use a 35-lb. pail either. The tractors needed the whole pail for the front ends, so there was nothing left for the pickups.
 
I have never heard any complaints about either brand. I think you will be better served by the 75-90, but thats mine and your choices. In my little town here in Idaho....you can buy Redline and RoyalPurple off the car parts shelfs.

I like the 5 gallon bucket method. If you fill both your axles (front and rear) I am sure a couple of gallons will be left over. I have alway's used Amsoil's FGR gear lubes without any problems. You can buy them in Qts, Gallons, 5 Gallons, etc..etc.
 
You are hooked up to a stock trailer most of the time... go with the 75-140, I would just for the little bit of extra protection. I use it and never had a problem in single digit temps.
 
best gear protection equals the thickest oil for you temp range you can run. I'd run 75/140.

I use RL 75/140 front and rear in my Expy.
bruce
 
With gear sets I think thicker is better and with the application I doubt you would see ANY difference in MPG or power between the 75-140 and 75/80-90. I didn't notice any MPG difference in my Ranger going from 80-90 to 75-140 and that doesn't have any HP to start with! Similar results with my F-350, no change is MPG or power but the diff temps were down about 15-20 degrees while towing with an Eaton LL synthetic fluid.

My 0.2 worth go with 75-140 RL with out the friction modifier and drive on!
 
I think you meant why do you think I would be better served with 75-90?

Film strength "Shear strength" will be the same with synthetic gear lube 75-90 as 75-140 and you will be going "Thinner" for a year round protection and better mileage. Severe gear from Amsoil has the additives in the gear lube to supply your needs! Thin is sheek...
 
Why are you not looking a Specialty Formulations? MolaKule seems well respected here and from what I understand he makes a great product. His gallon prices are fair. I'll be ordering from them this week.

The thing I like about Specialty Formulations is a real person answers all my silly question! Just give them a few days.
 
I have been looking at the Amsoil and Specialty Formulations products as well. The higher vis stuff will only really have benefit for low speed high torque apps?
 
bruce381, please show the proof "proven time and a time again" I am open to results and am open enough to changing my evil way's.

I have tried both weights and I like the thinner stuff...its sheek! just kidding.

Any Data?
 
quote:
Originally posted by Strjock81:
I have been looking at the Amsoil and Specialty Formulations products as well. The higher vis stuff will only really have benefit for low speed high torque apps?
Click to expand...
which is exactly what you haveevery time you start that 24 ft gooseneck from a standstill.
especially behind a diesel pp.
 
"Film strength "Shear strength" will be the same with synthetic gear lube 75-90 as 75-140 and you will be going "Thinner" for a year round protection and better mileage. Severe gear from Amsoil has the additives in the gear lube to supply your needs! Thin is sheek... "

Thin is not IN sorry in gear sets proven time and time again run highest vis you can that will still flow for your temp range.
Syns such as RL/Amsoil will flow at low temps well so use a 75/140.
bruce
 
quote:
which is exactly what you haveevery time you start that 24 ft gooseneck from a standstill.
especially behind a diesel pp.

LargeCars/Bigrigs start and stop all day long with gross weights of 80to120 thousand pounds using 75-90 or 75-140 gear lube. These Rigs have massive torque and gut wrenching action.

I see the Ring and Pinion as tightly meshed and I really don't think any oil can keep them from touching...these gears are not bearings, so we can't think of them as so. I would think of the ring and pinion action with oil as the cooler with minor lube action.

But the bearings and races are seperated by oil films. So would a heaver oil work will with them..So I guess the question would be....does 140 lube gear oil really do anything more in the ring and pinion set than 90? What does the additional thickness do? Remember, it does not keep the ring and pinion from touching.

Any experts? Rebuilders out there?
 
"bruce381, please show the proof "proven time and a time again" I am open to results and am open enough to changing my evil way's."

Bob Erichello of Geartech the most experienced
gear guy I know aswell as Jack Zakarian of Chevron (spelling?) sorry Jack say so.

Bob has over 40 years trouble shooting gear sets all over the world. Jack Z is Mr. gear at Chevron he also knows his stuff.

I sat through a few of his talks on gear distress and he knows his stuff. And when Bob says so I believe him, You do not have to that is your problem not mine.
bruce
 
Well they are very experienced folks bruce...and thank you for sharing this information. Folks like them and you are in the inside part of the lube business and I don't have a "problem" with that.

Regards,
LCM
 
Well I didn't mean to start a cat fight over who knows what film thickness is best, and who has better evidence to back it up!

To let my truck have a say in this, I guess I am just going to flip my no-longer-attached-to-turbo silencer ring in the air, between Amsoil vs. RP and then again for RL vs. Specialty Formulations. The winner of these two rounds will go head to head via another flip of the silencer ring, and then I will order their 75w-140.

Red Line did tell me that the friction modifier additive will reduce temps and friction even though I do not need it for my "anti-spin" differential to lockup, so I will get the LSD formula from wherever I get my gear lube.

Strangely I agonize over what 8 qts of gear oil I get for my pickup truck, yet I have older tractors with thousands of hours of heavy pulling, etc. running 80w-90, or 85w-140 petroleum gear oil, or petroleum Hy-Trans with no problems in them. These new things are so finicky!
 
Coin tossing
grin.gif
I do the same.

Pick ANY GL5 synthetic 140wt gear oil and use it. I'd pick the fluid that is cheapest and/or locally available.

The problem with gear-type diffs is that fluid weight and friction modifiers can affect the bias ratio. Thats something to consider if you're spinning tires in the slippery stuff often.
 
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