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Discussion Starter · #1 ·
So, I have determined that when I get home from deployment I will change my diff fluid. Its right around 50k, or will be when I get back, and though I consider that sort of early I have off roaded and towed enough to where I think it will be beneficial. As usual I searched the internet and the Z and couldn't find anything that answered my specific questions.

For the rear I will drain the fluid through the plug first, then pull the cover so I can inspect the gears. Its an LSD so its the one I'm more concerned about, and I want to make sure I clean out all the fuzz that is a byproduct of things with clutches (transmissions, clutch LSDs...). I'll be resealing it with silicone, nothing special there.

For the front I will probably just use the drain and fill plugs since its not an LSD, I am not too concerned with chipped gears or anything.

Now for the questions, I am probably overthinking this:

I really like Royal Purple, and want to use their max gear 75W-140. This says it already has LSD additive in it, but has anybody used it with a ZF LSD to confirm that it's enough? I don't want too much additive either, and I know you're supposed to add the additive before the oil. Should I put in 2 oz additive or something and then fill with the oil?

Redline also makes a 75W-140 without LSD additive (has "NS" at the end of the part number). They are supposed to make good gear oil, so I am considering just using this with the 5oz of Mopar LSD additive like the manual recommends. The Redline isn't MS-8985 compliant that I know of, but I am not super concerned with that since from what I can tell only the Mopar fluid is.

FWIW the Mopar LSD additive is the only one that meets the MS-10111 spec in the manual, but I am not super sure how important that is. I have always tried to comply with the manufacturer specs like MS-6395 for engine oil so I have only ever used Royal Purple other than dealer oil, which both meet the spec.

My 3rd option is to use Mopar diff fluid and Mopar LSD additive, but I feel like RP and Redline are probably higher quality. I have also read that the Mopar stuff has a higher level of sulfur in it :shy2:, of course that was on the internet so IDK how accurate it is.

For the front I can only find 2 companies that make a 75W-85 weight, Mopar and Redline. I know most people say just use 75W-90 but I am too neurotic to do that:LOL:. Anyway, I am going to use Redline up front, which actually has me leaning towards using the Redline 75W-140NS with Mopar LSD additive.

What are y'alls thoughts/opinions/experiences? Especially those of you with 2011+ ZF 9.25 LSDs.
 

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Morning TH!
If you are wanting to use something other than the Mopar lube
then I would go with the Redline.
I have used Redline in a number of my trucks with no problems.
No doubt the Mopar or Royal Purple would treat you the same tho.
Also I would just as soon have the same manufacturer in both axles!

BTW when do you leave and thank you for your service...
 

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You are WAY over thinking this. I know you love your truck and want to do the right thing but fretting over a 75w-85 and 75w-90 is going over the top in my book.

I do not have any experience with your exact axle or truck but I will tell you what I know...

The MS specs so many are concerned about here are paid advertisements, not magic formulas that are somehow better than the rest. Do not fall into that trap.

I think you could pick any decent brand of synthetic gear lube and get the same results. I have had good luck with all of them, Amsoil, Redline, Royal Purple, Mopar, Valvoline, Motorcraft...

The LSD additive issue... I have had very good luck with gear oils already containing the additive. I do not see what the difference would be if you bought it already mixed or did it yourself? Different axles will react differently. I had a dually that HAD to have additional LSD friction modifier or it would chatter. I have had some that didn't chatter with zero additive. The goal is to run just enough to make the clutches happy. I have used Motorcraft, Mopar and a couple aftermarket versions of LSD friction modifier, they all seemed to do the job.

I like your interval choice, 50k is a good time to get in there and do some fluid changes. Your methods are sound, no need to open up the front diff unless you have an issue. Whatever fluids you choose will be fine as long as you use good synthetics. I do not see fretting over small details, as you seemed to be doing, having any tangible reward.
 

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So, I have determined that when I get home from deployment I will change my diff fluid. Its right around 50k, or will be when I get back, and though I consider that sort of early I have off roaded and towed enough to where I think it will be beneficial. As usual I searched the internet and the Z and couldn't find anything that answered my specific questions.

For the rear I will drain the fluid through the plug first, then pull the cover so I can inspect the gears. Its an LSD so its the one I'm more concerned about, and I want to make sure I clean out all the fuzz that is a byproduct of things with clutches (transmissions, clutch LSDs...). I'll be resealing it with silicone, nothing special there.

For the front I will probably just use the drain and fill plugs since its not an LSD, I am not too concerned with chipped gears or anything.

Now for the questions, I am probably overthinking this:

I really like Royal Purple, and want to use their max gear 75W-140. This says it already has LSD additive in it, but has anybody used it with a ZF LSD to confirm that it's enough? I don't want too much additive either, and I know you're supposed to add the additive before the oil. Should I put in 2 oz additive or something and then fill with the oil?

Redline also makes a 75W-140 without LSD additive (has "NS" at the end of the part number). They are supposed to make good gear oil, so I am considering just using this with the 5oz of Mopar LSD additive like the manual recommends. The Redline isn't MS-8985 compliant that I know of, but I am not super concerned with that since from what I can tell only the Mopar fluid is.

FWIW the Mopar LSD additive is the only one that meets the MS-10111 spec in the manual, but I am not super sure how important that is. I have always tried to comply with the manufacturer specs like MS-6395 for engine oil so I have only ever used Royal Purple other than dealer oil, which both meet the spec.

My 3rd option is to use Mopar diff fluid and Mopar LSD additive, but I feel like RP and Redline are probably higher quality. I have also read that the Mopar stuff has a higher level of sulfur in it :shy2:, of course that was on the internet so IDK how accurate it is.

For the front I can only find 2 companies that make a 75W-85 weight, Mopar and Redline. I know most people say just use 75W-90 but I am too neurotic to do that:LOL:. Anyway, I am going to use Redline up front, which actually has me leaning towards using the Redline 75W-140NS with Mopar LSD additive.

What are y'alls thoughts/opinions/experiences? Especially those of you with 2011+ ZF 9.25 LSDs.
I would personally recommend just putting the RP in the rear and IF and only IF it chirps add one OZ of LSD additive until it stops. Otherwise the LSD is not going to be operating at "full" capability.

For the front Redline is good but is geared more toward racing applications, though it is still a great oil.


I don't really much care what manufacturer spec something meets because that is just a certification from said manufacturer and not something like ISO spec. The latter is what really matters IMO.
 

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Discussion Starter · #5 ·
I would personally recommend just putting the RP in the rear and IF and only IF it chirps add one OZ of LSD additive until it stops. Otherwise the LSD is not going to be operating at "full" capability.

For the front Redline is good but is geared more toward racing applications, though it is still a great oil.


I don't really much care what manufacturer spec something meets because that is just a certification from said manufacturer and not something like ISO spec. The latter is what really matters IMO.
If it chirps then the clutches have already slipped, meaning that they have already been damaged and got more fuzz floating around in the diff, so I want to avoid that right after the change.

What makes it more of a "racing oil" than any other 75W-140?
 

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I do not think, you are over thinking this.
I too want my truck to last a long time.

So, read, learn, get advice.

Then post back just what you do and how you did it.
Because that is what I am going to do too.

PS
SO glad you are ready now. I just started reading up on all this stuff, last couple of weeks. Truck is getting close to 20K miles and figured it would take me awhile to figure it all out.

Now, I don't have too.
You more anal than I am.
 

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If it chirps then the clutches have already slipped, meaning that they have already been damaged and got more fuzz floating around in the diff, so I want to avoid that right after the change.

What makes it more of a "racing oil" than any other 75W-140?
You only need to partially make one turn to hear if it is chirping, easy to do and really won't hurt anything.

Redline was a company that was founded to appeal to and provide for serious race teams that abuse the moving parts of their vehicles in very high speed and stress situations, I think their website has a section that explains their history if you want to read through it.
 

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thunder, have you considered going for an aftermarket dif cover when you change the rear fluid? i would stick with the mopar fluid.
 

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Discussion Starter · #9 · (Edited)
You only need to partially make one turn to hear if it is chirping, easy to do and really won't hurt anything.

Redline was a company that was founded to appeal to and provide for serious race teams that abuse the moving parts of their vehicles in very high speed and stress situations, I think their website has a section that explains their history if you want to read through it.
So...high speed + high stress = high heat = what a diff experiences when towing right?

thunder, have you considered going for an aftermarket dif cover when you change the rear fluid? i would stick with the mopar fluid.
I have, I have looked at the Mag-Hytec, however looking at it I am not sure I like how the dipstick just hangs in there like that. really I don't see a need for a dipstick in a diff since its not like an engine that can consume oil and if its leaking I'd be able to tell and check the level through the fill hole. Also, it comes mighty close to the sway bar. Additionally, the quantity of LSD additive is based on getting the right proportion of additive to oil. Increasing the amount of oil would increase the required amount of additive required and I'm not sure what the stock cover and MH capacities are to work out the proportion and figure out how much additive I would then need.

I'm still thinking about it though. I just don't know how necessary it is vs the stock cover; the $250 doesn't bother me too much. I can only find one for Rams with the 9.25 diff, is it the same part for the 2011 ZF ones as it is for the older AAM ones used since at least the 2nd gens? Also, the magnet is on the bottom of the housing right, not the cover? Definitely do not want to lose that feature.

FWIW right now I am thinking I will use Redline NS and Mopar additive so I will have Redline in both pumpkins to satisfy my diseased mind.


MountainRam06 is reading this like: "WTF did I just say man?:doh::doh::doh:"

:LOL:
 

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So...high speed + high stress = high heat = what a diff experiences when towing right?



I have, I have looked at the Mag-Hytec, however looking at it I am not sure I like how the dipstick just hangs in there like that. really I don't see a need for a dipstick in a diff since its not like an engine that can consume oil and if its leaking I'd be able to tell and check the level through the fill hole. Also, it comes mighty close to the sway bar. Additionally, the quantity of LSD additive is based on getting the right proportion of additive to oil. Increasing the amount of oil would increase the required amount of additive required and I'm not sure what the stock cover and MH capacities are to work out the proportion and figure out how much additive I would then need.

I'm still thinking about it though. I just don't know how necessary it is vs the stock cover; the $250 doesn't bother me too much. I can only find one for Rams with the 9.25 diff, is it the same part for the 2011 ZF ones as it is for the older AAM ones used since at least the 2nd gens? Also, the magnet is on the bottom of the housing right, not the cover? Definitely do not want to lose that feature.

FWIW right now I am thinking I will use Redline NS and Mopar additive so I will have Redline in both pumpkins to satisfy my diseased mind.


MountainRam06 is reading this like: "WTF did I just say man?:doh::doh::doh:"

:LOL:
As far as the cover and magnet location, yes it's all the same.
 

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Discussion Starter · #11 ·
Ok so after doing more research I am concerned that the MH may get hit by a) the sway bar b) the panhard bar or c) the crossmember on the frame if it is loaded enough. Can anyone confirm that it will not touch anything even when loaded to the bump stops or fully articulated? It may never happen, but it only takes 1 hit to crack an aluminum diff cover and then there goes all your oil and gears with it.
 

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Ok so after doing more research I am concerned that the MH may get hit by a) the sway bar b) the panhard bar or c) the crossmember on the frame if it is loaded enough. Can anyone confirm that it will not touch anything even when loaded to the bump stops or fully articulated? It may never happen, but it only takes 1 hit to crack an aluminum diff cover and then there goes all your oil and gears with it.
Uh I would not do it if that is the case, I would rather use the stock cover and not risk losing the whole diff as there is no easy way to tell if the thing is broke when driving it.

Would hate to see it be fine 99% of the time and then on one hard bump have it breach.
 

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thunder, i put the maghy on my wrangler. i like the extra cooling with the built in fins. i only tow light loads with the ram and never goes off road so i cant answer your questions.
 

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Discussion Starter · #14 ·
Update: I looked at the Redline oil more closely on their site and noticed that their friction modifier they use in their gear oil can also be purchased separately. Looking under the technical information on the website it says that their additive "Satisfies performance requirements of Chrysler 4318060". At first I thought "what a bummer, Chrysler specifies that I need a friction modifier that meets their MS-10111 spec".


Then I realized that 4318060 is the part number for the Chrysler friction modifier that meets the MS-10111 spec, not the actual Chrysler spec that the additive meets. :thk:

So I have finished up making up my mind now: I will use Redline 75W85 GL-5 gear oil in the front,

http://www.redlineoil.com/product.aspx?pid=40&pcid=4

Redline 75W140-not the NS, but the kind with friction modifier already in it-in the rear. Their additive meets the Chrysler spec per the above information so i should be good.

http://www.redlineoil.com/product.aspx?pid=134&pcid=4

I will also get a bottle of their FM to keep on hand in case of any popping so I can up the dosage if I need to. Its half the price of the Mopar additive anyway.

http://www.redlineoil.com/product.aspx?pid=41&pcid=4


I hope this helps someone who may have had similar concerns:wavey:
 
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