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Limited slip=yes, friction modifier.....yes and no

desert_wagon

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so as the title states, 2020 PW limited slip yes, online manual says no friction modifier required, pdf say yes a friction modifier is required. So....anyone really know? Also is the limited slip really a limited slip or that psuedo-brake-controlled "limited slip"?
 

H3LZSN1P3R

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It is a limited slip should be listed as anti spin. What does your owners manual say?
 

el_barto

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I haven’t checked for certain on the 2019s (by jacking up the rest axle and turning a wheel), so maybe something changes(doubt it).... but the power wagon has always had the AAM TracRite GTL rear differential, which is a helical gear limited slip differential PLUS electronic locker. And TracTite EL in the front (open with electronic locker)

So yes to friction modifier in the rear
 

AnthonyD1978

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Can you clarify why modifier wouldn’t be needed? We agree it’s the AAM GTL, which is a limited slip differential.

I have another 50k miles to go before I do a diff fluid change so I haven't looked into it too much. I don't think the GTL uses a clutch pack for LSD function. So it wouldn't need a modifier. Though, using a modifier when it's not needed shouldn't hurt anything.
 

jadmt

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I have another 50k miles to go before I do a diff fluid change so I haven't looked into it too much. I don't think the GTL uses a clutch pack for LSD function. So it wouldn't need a modifier. Though, using a modifier when it's not needed shouldn't hurt anything.
Correct
 

jadmt

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Can you clarify why modifier wouldn’t be needed? We agree it’s the AAM GTL, which is a limited slip differential.
as posted above ours have no clutch packs Which is the reason for modifiers.
 

el_barto

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I have another 50k miles to go before I do a diff fluid change so I haven't looked into it too much. I don't think the GTL uses a clutch pack for LSD function. So it wouldn't need a modifier. Though, using a modifier when it's not needed shouldn't hurt anything.
You are correct it is a helical gear LSD similar to Torsen, not clutch pack style. Looking on the AAM website, they explicitly say “the GTL does not need friction additives”

I’m guessing Ram suggests it in their manual because this Torsen webpage says it can quiet the LSD down.

 

jadmt

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remember the manual is written for all variations of RAM 2500/3500 so always going to have things slip through the cracks.
 

el_barto

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remember the manual is written for all variations of RAM 2500/3500 so always going to have things slip through the cracks.
The regular “anti-spin” diff in the 2500/3500 is the TracRite GT, which is the same, helical gear LSD.
Im guessing, as I mentioned above, they suggest friction modifier to quiet down any squealing ... or whoever wrote the manual just didn’t know what type of LSD is used.
 

AnthonyD1978

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I was going to change mine at 60k miles. What conditions/miles are you guys changing yours?

I used to change mine out in my cars every year (I did track days in them a few times a year).
 

jadmt

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I was going to change mine at 60k miles. What conditions/miles are you guys changing yours?

I used to change mine out in my cars every year (I did track days in them a few times a year).
I would not go 60,000 miles if it were mine but that is just me. every 15,000 seems reasonable. I think if you do water crossings and have not raised your vent tubes I would worry even with the one way valve. I had like 2000 miles on mine because I changed covers and it was clear as could be but even knowing that probably change the first time at 15,000 and see how it looks and adjust from there. mine had no whiskers on the magnet but others have reported they have had build up so just for that reason.
 

AnthonyD1978

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I would not go 60,000 miles if it were mine but that is just me. every 15,000 seems reasonable. I think if you do water crossings and have not raised your vent tubes I would worry even with the one way valve. I had like 2000 miles on mine because I changed covers and it was clear as could be but even knowing that probably change the first time at 15,000 and see how it looks and adjust from there. mine had no whiskers on the magnet but others have reported they have had build up so just for that reason.

Yes thank you, 15k for sure for the my first change and determine from there. I'm not sure what I was thinking at 60k. Maybe the transfer case which I think the manual says to change at 100k. Yes, already raised all the breather lines for the drivetrain.
 
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desert_wagon

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I will be swapping out xfer case/diffs and oil at 2k, new truck = leftover metal in the bottom of the pans/pumpkins. So better to flush it and replace, then gtg for another 15k'ish(exceopt the oil of course)
 

AnthonyD1978

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I will be swapping out xfer case/diffs and oil at 2k, new truck = leftover metal in the bottom of the pans/pumpkins. So better to flush it and replace, then gtg for another 15k'ish(exceopt the oil of course)

May as well do your transmission while you're at it.

Out of curiosity I called me dealer for the front and rear diff. They wanted $440 lol. I'll be doing it myself. Wish our diffs had a drain plug like my cars always had.
 

el_barto

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May as well do your transmission while you're at it.

Out of curiosity I called me dealer for the front and rear diff. They wanted $440 lol. I'll be doing it myself. Wish our diffs had a drain plug like my cars always had.
FWIW the ZF specifies the fluid in the 8HP transmission be changed every 50k-75k miles, or Max 8 year interval if mileage not reached.
The Pan is plastic and has an integrated filter. The Pan needs to be replaced when the fluid is replaced.
The oil is pretty pricey and the filling process very specific, but my understanding is it is DIY-able.
 

jadmt

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May as well do your transmission while you're at it.

Out of curiosity I called me dealer for the front and rear diff. They wanted $440 lol. I'll be doing it myself. Wish our diffs had a drain plug like my cars always had.
the nice thing is these have a reusable gasket. $440 is nuts. I used mopar gear oil which is stupid priced at $17.35 a bottle. The rear takes a bit over 3.5 quarts. so they are hosing you on labor as they should be able to do both in under an hour.
 

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