Does Royal Purple's rear gear oil have enough of a slip additive or will I need to add in addition to it?

[WILDHOBO]

The guy who posted directly after you and this guy on Amazon. So 2 ppl required an additive due to a clunky diff post valvoline oil fill and 2 did not in this thread alone. Not everything is black and white it seems

Can you do harm by adding more modifier than necessary? If not, I may just start doing it for some overkill.

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[WILDHOBO]

Here comes a layup….

Mine doesn’t clunk, but screw it. Who doesn’t like lube?

 

[ShadowsPapa]

The guy who posted directly after you and this guy on Amazon. So 2 ppl required an additive due to a clunky diff post valvoline oil fill and 2 did not in this thread alone. Not everything is black and white it seems

The guy on amazon doesn't state what vehicle, the age of his vehicle or type of limited slip setup he has. So it's one of those "I take it for what it's worth" things.

It's one of those areas where most will have no trouble, but if you do - add some additive. (and by most, I mean probably 90% won't have issues)

Try it without - the specs are fill to 1/8" below the bottom of the fill hole, so there's more than enough room for additive later. These don't have to run topped off. Simple - add some additive if needed.

 

[WILDHOBO]

The guy on amazon doesn't state what vehicle, the age of his vehicle or type of limited slip setup he has. So it's one of those "I take it for what it's worth" things.

It's one of those areas where most will have no trouble, but if you do - add some additive. (and by most, I mean probably 90% won't have issues)

Try it without - the specs are fill to 1/8" below the bottom of the fill hole, so there's more than enough room for additive later. These don't have to run topped off. Simple - add some additive if needed.

The 1/8” level thing is hard to use, unless your truck is at stock ride height with no changes. With a significant lift in the rear and a slightly raised pinion angle, I’ve just been filling until it drips out the hole.

 

[ShadowsPapa]

The 1/8” level thing is hard to use, unless your truck is at stock ride height with no changes. With a significant lift in the rear and a slightly raised pinion angle, I’ve just been filling until it drips out the hole.

The goofy thing is people get hung up on a differential being below the hole - these have been fine with up to an inch below the hole. They aren't lubricated by the height of the lube inside - it's a splash lube system and as long as the ring gear can grab sufficient lube and throw it around, the bearings will be fine.
I'm not a bit concerned about the level being a bit below the fill hole.
If you have really moved the pinion angle due to lift and needing to keep that rear joint fairly straight, that's another matter - you don't want to run those real low - heat will be your enemy there, and the splash pattern is disturbed.

I keep various suction guns, huge syringes, pumps and other stuff around to withdraw and/or add fluids, so not a biggy, I guess.

 

[WILDHOBO]

The goofy thing is people get hung up on a differential being below the hole - these have been fine with up to an inch below the hole. They aren't lubricated by the height of the lube inside - it's a splash lube system and as long as the ring gear can grab sufficient lube and throw it around, the bearings will be fine.
I'm not a bit concerned about the level being a bit below the fill hole.
If you have really moved the pinion angle due to lift and needing to keep that rear joint fairly straight, that's another matter - you don't want to run those real low - heat will be your enemy there, and the splash pattern is disturbed.

I keep various suction guns, huge syringes, pumps and other stuff around to withdraw and/or add fluids, so not a biggy, I guess.

Agreed. As do I. It’s like a boat’s lower unit. Fill it up. I need to rig up a threaded pump in adapter that could use my drain hole threads. Pump in from the bottom until it comes out the top. Plug the top and then plug the bottom. No air bubbles.

 

[bd100]

Can you do harm by adding more modifier than necessary? If not, I may just start doing it for some overkill.

Too much may reduce the effectiveness of the limited slip function, supposedly.

 

[ShadowsPapa]

Too much may reduce the effectiveness of the limited slip function, supposedly.

Yes, you can actually cause it to be "too slippery" not allowing the clutches to lock.
That's why I always simply put in the lube - and since by specs on a normal vehicle it's below the hole a bit anyway, there's always room for the additive later - if needed.

 

[WILDHOBO]

Yes, you can actually cause it to be "too slippery" not allowing the clutches to lock.
That's why I always simply put in the lube - and since by specs on a normal vehicle it's below the hole a bit anyway, there's always room for the additive later - if needed.

Granted, with a locker I don’t technically have lsd, but it calls for the modifier. I’ve never added extra and never had knocking.

 

[ShadowsPapa]

Granted, with a locker I don’t technically have lsd, but it calls for the modifier. I’ve never added extra and never had knocking.

I'm glad you didn't admit to having lsd in a public forum...................

anyway, not having had a "Tru-Lok" axle before - I've never paid attention to the lube required for those. I'll have to deal with that on the new one as it's got the locking rear....... wish it was LSD instead, but if that's the only drawback, I'll either live with that or switch in the future.

 

[Wheelin98TJ]

Granted, with a locker I don’t technically have lsd, but it calls for the modifier. I’ve never added extra and never had knocking.

The owners manual states friction modifier is required for Trac-Lok equipped axles. I don't see it mentioned you need it with your Tru-Lok locker. Where did you see it was needed?

 

[WILDHOBO]

I'm glad you didn't admit to having lsd in a public forum...................

anyway, not having had a "Tru-Lok" axle before - I've never paid attention to the lube required for those. I'll have to deal with that on the new one as it's got the locking rear....... wish it was LSD instead, but if that's the only drawback, I'll either live with that or switch in the future.

You’ll love the locker.

 

[ShadowsPapa]

You’ll love the locker.

We'll see. I relied a LOT on the LSD while plowing snow and going around TIGHT turns with the load. Can't do that with the axles locked. We'll just have to find out. With luck, the electronics will handle it. I never once heard any "brake chatter" when plowing snow. I don't have wide open spaces, so have to have the front wheels cranked a lot.
My gut tells me I'll probably never touch that switch!

At least I know it has SelecTrac transfer case.

It should be fine.

 

[Hootbro]

Problem is there is almost no information from many of the gear oil companies that advertise their gear fluids having anti-slip additive as to what type and concentration?

While I agree too much additive can be detrimental, I have never seen it to be an issue of anybody adding the OEM amount recommended additive on top of what a gear oil that claims to have in it for anti-slip additive.

I guarantee most people pour in the whole 4oz bottle of MOPAR anti-slip additive when it only calls for 2.7oz of it.

 

[ShadowsPapa]

Problem is there is almost no information from many of the gear oil companies that advertise their gear fluids having anti-slip additive as to what type and concentration?

While I agree too much additive can be detrimental, I have never seen it to be an issue of anybody adding the OEM amount recommended additive on top of what a gear oil that claims to have in it for anti-slip additive.

I guarantee most people pour in the whole 4oz bottle of MOPAR anti-slip additive when it only calls for 2.7oz of it.

LOL... I guess I'm not most people

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