Diff fluid questions!!

[Kb1229]

Hey,I got a 2013 ram 1500 5.7 4x4 and today received a delivery of royal purple max gear with friction mod add 75/90 for the front and 75/140 for the rear as per my manual .

I've read on other posts guys using 75/85 for the front diff,so my question is

Front diff 75/90
Rear diff 75/140 does this work?

Is there any need to add additional mopar limited slip add?

Any other info will be appreciated first time doing this metiance

 

[Octane]

Hey,I got a 2013 ram 1500 5.7 4x4 and today received a delivery of royal purple max gear with friction mod add 75/90 for the front and 75/140 for the rear as per my manual .

I've read on other posts guys using 75/85 for the front diff,so my question is

Front diff 75/90
Rear diff 75/140 does this work?

Is there any need to add additional mopar limited slip add?

Any other info will be appreciated first time doing this metiance

Pour it in and ride.That diff can't tell the difference between a 75/85 and 75/90.Use normal amountof friction mod .If the bottle says it has the friction mod in it some say you dont have to add any more to it.But I do.

 

[Longhorn1500]

Pour it in and ride.That diff can't tell the difference between a 75/85 and 75/90.Use normal amountof friction mod .If the bottle says it has the friction mod in it some say you dont have to add any more to it.But I do.

You only need the friction modifier if you have the LSD, right?

 

[Kb1229]

Correct, in the manual its calls for the friction mod for the rear only!!

 

[gixxer]

You only need the friction modifier if you have the LSD, right?

Correct, otherwise it does nothing.

Some of the boutique oils come with it so you don't need to add extra.

 

[Burla]

All modern diffs even open diffs all use the allinone gear fluid. The manufacturers spec the same oil for open or limited slip diffs, and all of the fluids have the additive in it. Most OTC brands don't even offer fluid w/o the modifier in it, as in m1 like here. Occasionally some guys have to add more if they get shudder, but it is rare, and since this is all that is available anymore, it has taken the guess work out of it. RP goes a step further and even recommends it for manual gear box, never looked into why that would be. I would research brands of gear fluids, amsoil has done some eye opening studies on this..

 

[Octane]

All modern diffs even open diffs all use the allinone gear fluid. The manufacturers spec the same oil for open or limited slip diffs, and all of the fluids have the additive in it. Most OTC brands don't even offer fluid w/o the modifier in it, as in m1 like here. Occasionally some guys have to add more if they get shudder, but it is rare, and since this is all that is available anymore, it has taken the guess work out of it. RP goes a step further and even recommends it for manual gear box, never looked into why that would be. I would research brands of gear fluids, amsoil has done some eye opening studies on this..

I've always questioned if the proper amount of of modifier in bottles.They wouldnt 4 oz. of it in every bottle surely

 

[kurek]

I don't think the ratio of additive is comparable between LSD-ready gear oils and uh.. ****** ones for lack of a better term. In the end it's some clutch-friendly amount of grip/slip they're aiming for and the active ingredient which produces that effect may only take a gram per liter. The additive tubes might already be watered down, in other words, to facilitate easy pouring or to buffer any possible reactivity when mixed with whatever random oil you're using.

 

[Octane]

I don't think the ratio of additive is comparable between LSD-ready gear oils and uh.. ****** ones for lack of a better term. In the end it's some clutch-friendly amount of grip/slip they're aiming for and the active ingredient which produces that effect may only take a gram per liter. The additive tubes might already be watered down, in other words, to facilitate easy pouring or to buffer any possible reactivity when mixed with whatever random oil you're using.

For instance,my Challenger required say...2.5 quarts on a change.I was told to add 4oz. of modifier.If those bottles already had 4 oz between them that would mean each bottle a little more than an ounce in each bottle.And they dont tell you the amount tho.So I just add my 4 oz. and be done with it.

 

[Burla]

For instance,my Challenger required say...2.5 quarts on a change.I was told to add 4oz. of modifier.If those bottles already had 4 oz between them that would mean each bottle a little more than an ounce in each bottle.And they dont tell you the amount tho.So I just add my 4 oz. and be done with it.

Just for info sakes,too much additive is bad for limited slip according to Dave at redline, and if your gear fuid already has additive in it and you are blindly tossing in another max dose, you may be not doing yourself a favor, if I read that right. Even redline's site they say only add an ounce at a time to eliminate shudder, never toss in full 4 ounces.

From redline...

LIMITED-SLIP FRICTION MODIFIER

• Compatible with both petroleum and synthetic gear oils
• Reduces break-in temps as much as 50°F
• Add 1oz at a time to clutch-type limited slip or posi-traction units to eliminate chatter

 

[tidefan1967]

Changed mine for the first time to Redline 75W140 week before last and she’s quiet as a church mouse. I also have the 3.92 LS setup. Didn’t add anything extra and it’s noticeably quieter than it was with the Mopar stuff to me. I don’t think you need to add any extra but I doubt it hurts anything if it helps you sleep better at night.

 

[Octane]

Just for info sakes,too much additive is bad for limited slip according to Dave at redline, and if your gear fuid already has additive in it and you are blindly tossing in another max dose, you may be not doing yourself a favor, if I read that right. Even redline's site they say only add an ounce at a time to eliminate shudder, never toss in full 4 ounces.

From redline...

LIMITED-SLIP FRICTION MODIFIER

• Compatible with both petroleum and synthetic gear oils
• Reduces break-in temps as much as 50°F
• Add 1oz at a time to clutch-type limited slip or posi-traction units to eliminate chatter

So each bottle has a ounce?

 

[Different Drummer]

Annnnnd, if you happen to have a Torsen style LSD the additive and / or synthetic lube may have an adverse effect on how it does it's torque bias thing. This of course would not include clutch type LSD or open Diff's. Just something to keep in mind if you have a 2500-3500 LSD or aftermarket Torsen type modified rear differential.

 

[Kb1229]

Thanks for all the replies I learned a lot of valuable information!!

 

[Burla]

So each bottle has a ounce?

Not sure of the ratio, and not sure ounce applies in a larger formula. In other words, the reason why they might put in in 4 ounce sizes might be modifier and carrier oil for measurement purposes. I'm sure the amount that ends up in a quart is the correct ratio, otherwize they would get alot of complaints. The specs and oem specs are usually listed, it appears the generic allinone gl-5 meets like 99% of the specs out there. Gear fluids haven't changed in a long time, I never even heard a gl-6 being on the horizon.

 

[MRFREEZE57]

Changed mine for the first time to Redline 75W140 week before last and she’s quiet as a church mouse. I also have the 3.92 LS setup. Didn’t add anything extra and it’s noticeably quieter than it was with the Mopar stuff to me. I don’t think you need to add any extra but I doubt it hurts anything if it helps you sleep better at night.

I put the Redline in the rear end earlier this year, it does have the LSD and do not notice any chattering. Redline says it has the additive for the LSD.