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HSKR R/T

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Thanks for your help @UnloosedChewtoy and my apologies to the OP who clearly called out on the video that 3 quarts are required for the rear diff fluid change. I couldn't find the Amsoil Bags so I went with Mobil1. Rear diff fluid level was definitely low as there was no drip once fill plug was opened. Probably just imagining this but I swear the drivetrain is quieter now...

Knocked this out in 15-20 min - very simple process thanks to the contributions here.
There should be no fluid dripping out from fill plug. The correct fill level is about 1/4" below the fill plug. If you added fluid until it ran out, you have over filled your differential
 

c3k

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Not to bring up a old topic. I have a elocking 392 rear. If I’m reading the chart correctly that doesn’t get the friction additive? Is that correct?

Correct.

Electronic Locking Differential does not have friction clutches. No clutches, no need for the additive that prevents the clutches from binding. ("Binding" = "engaging when they shouldn't")

*************************************************

Found the above sitting in my "reply to" window when I woke up. I guess I forgot to send it. Here it is now. (Better late than never?)
 

kapinallinen2

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It's not "up to" the bottom of the hole, it's 1/8" from the bottom. Sure, it gives a variance, but the correct level is below fill hole, not at the fill hole
Call me old fashioned but when I replace my differential lube I will fill it till it flows out of the fill hole.
 

HSKR R/T

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Call me old fashioned but when I replace my differential lube I will fill it till it flows out of the fill hole.
Not sure how thrs "old fashioned" as my "old fashioned* Chrysler 9.25 diff in my 99 Dakota called for 1/4" below fill hole as well.
 

kapinallinen2

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Not sure how thrs "old fashioned" as my "old fashioned* Chrysler 9.25 diff in my 99 Dakota called for 1/4" below fill hole as well.
My `72 AMX, `86 Bronco, `90 Bronco, `92 Exploder, `97 Expedition and daughters 2000 GC did not suffer any ill effects from filling to the bottom of fill hole.
Therefore I will stick to my old fashioned way of doing this service.
edit: my `62 Healy suffered no ill effects either... :D
 

kapinallinen2

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Based off this is 3mm or 1/8th plus or minus. The way that reads to me is it could be 0mm (to the fill level) or 1/8" below it.

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The way I read it is that the proper fill level is 1/8th below fill hole.
The +- variation allows for it to be 1/8th below proper fill level or 1/8 above proper fill level.
 

TheWaterman83

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First off, this thread answered a question one of my questions re: no need for the friction modifier in the e-locker 3.92. The way I read the fill spec is +/- 3mm or +/- 1/8" from bottom of fill hole. It can be as low as 3mm or 1/8" down from the bottom of fill hole OR up to the bottom of fill hole. Bottom line is: I don't think going up to the bottom of the fill hole is going to cause any harm. Theoretically, what if someone is doing it their unlevel driveway? They always state "Perform service with vehicle on level surface." Shop lifts aren't even level sometimes. My interpretation, is if anything, they are specifying that so the differential is not underfilled. Overfilling is possible but you would need to be a special type of person to do that lol.
 

GKIII

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The way I read it is that the proper fill level is 1/8th below fill hole.
The +- variation allows for it to be 1/8th below proper fill level or 1/8 above proper fill level.
This is correct, 3mm above nominal is within spec. With that said, this is a differential....3mm above the nominal fill level isn't going to hurt a damn thing.
 

JoshK

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Hello, is it not necessary to remove the rear diff cover? im getting ready to change the fluids and originally was told i was gunna need to do that but every how-to i find does just as you did above.
 

1BADRAMLIMITED

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Hello, is it not necessary to remove the rear diff cover? im getting ready to change the fluids and originally was told i was gunna need to do that but every how-to i find does just as you did above.
no need to remove the cover just remove the fill plug 1st then the drain and so on
 

PatriotLonghorn

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Yep, just did mine last week, diffs and transfer case. The rear diff is 8mm hex fill and 14mm hex drain.
 

c3k

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Yeah...gotta give some praise to the RAM engineers for having fill AND drain plugs on both diffs (front and back) and the transfer case. I have always been dumbfounded at the need to remove diff covers, then seal them (and almost every sealant instructs to wait at least 24 hours for curing before adding any fluid), and THEN refill.

Having drain plugs makes fluid swaps a 15 minute job. Having to remove the cover and let the sealant cure takes a truck out of operation for at least a day...for basic fluid maintenance.

Ditto for transmission pans.

Imagine if oil pans did not have drain plugs? You'd have to do the same crap.

Anyway...when I found all the drain plugs under my truck, I gave a cheer to RAM.
 

HSKR R/T

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Yeah...gotta give some praise to the RAM engineers for having fill AND drain plugs on both diffs (front and back) and the transfer case. I have always been dumbfounded at the need to remove diff covers, then seal them (and almost every sealant instructs to wait at least 24 hours for curing before adding any fluid), and THEN refill.

Having drain plugs makes fluid swaps a 15 minute job. Having to remove the cover and let the sealant cure takes a truck out of operation for at least a day...for basic fluid maintenance.

Ditto for transmission pans.

Imagine if oil pans did not have drain plugs? You'd have to do the same crap.

Anyway...when I found all the drain plugs under my truck, I gave a cheer to RAM.
It's good to pull the cover every now and then to inspect the insides. Especially on the older 9.25 with limited slip where the clutch pack holders would break and fall into the bottom and get chewed up in gear set.

As for sealant, use The Right Stuff and it has a shorter cure time and seals better than many others.
 

myfast3rdgen

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First off, this thread answered a question one of my questions re: no need for the friction modifier in the e-locker 3.92. The way I read the fill spec is +/- 3mm or +/- 1/8" from bottom of fill hole. It can be as low as 3mm or 1/8" down from the bottom of fill hole OR up to the bottom of fill hole. Bottom line is: I don't think going up to the bottom of the fill hole is going to cause any harm. Theoretically, what if someone is doing it their unlevel driveway? They always state "Perform service with vehicle on level surface." Shop lifts aren't even level sometimes. My interpretation, is if anything, they are specifying that so the differential is not underfilled. Overfilling is possible but you would need to be a special type of person to do that lol.

Speaking to only the 3.92 e-locker...

No additional friction modifier is needed or that the fluid must not contain any friction modifier?

I ask because it seems most if not all the SAE 75W-140 already contain the frication modifier. AMSOIL SAE 75W-140 says "Contains friction modifiers for limited-slip applications"
 
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LaxDfns15

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Speaking to only the 3.92 e-locker...

No additional friction modifier is needed or that the fluid must not contain any friction modifier?

I ask because it seems most if not all the SAE 75W-140 already contain the frication modifier. AMSOIL SAE 75W-140 says "Contains friction modifiers for limited-slip applications"
I have the 3.92 locker and used AMSOIL 75W-140 per their website. The additional friction modifier is needed for the LSD, so nothing extra for ours.
 

c3k

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Speaking to only the 3.92 e-locker...

No additional friction modifier is needed or that the fluid must not contain any friction modifier?

I ask because it seems most if not all the SAE 75W-140 already contain the frication modifier. AMSOIL SAE 75W-140 says "Contains friction modifiers for limited-slip applications"

With an e-locker, friction modifier (present or not), makes no difference to the function of the diff.
 

TheWaterman83

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Speaking to only the 3.92 e-locker...

No additional friction modifier is needed or that the fluid must not contain any friction modifier?

I ask because it seems most if not all the SAE 75W-140 already contain the frication modifier. AMSOIL SAE 75W-140 says "Contains friction modifiers for limited-slip applications"

Friction modifier in a diff that doesn't need = no problem.

No friction/not enough friction modifier in a diff that DOES need = PROBLEM
 

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