Rear differential fill

[wallyuwl]

Are they still filling the rear differential low from the factory?

 

[SD Rebel]

I don't think it was a widespread issue, mine was a late 2019 build and had a full diff.

However, I recommend checking anyways, it's a pretty simple check, just remove the fill bolt and inspect the level.

Note that the fill and drain plugs are on the right side (passenger side) of the differential, no longer on the back cover. The fill plug is an 8mm allen. As you are about to remove the fill plug, fluid should start coming out, then immediately tighten.

If no fluid comes out, either it's cold or low. Use a flashlight and tip of your finger to see where the level is at, If you can't feel or see the fluid, it's too low.

 

[wallyuwl]

Thx. My 2020 was 3/4 quart low. Looking for someone I know getting a 2022.

 

[Cbty2050]

I don't think it was a widespread issue, mine was a late 2019 build and had a full diff.

However, I recommend checking anyways, it's a pretty simple check, just remove the fill bolt and inspect the level.

Note that the fill and drain plugs are on the right side (passenger side) of the differential, no longer on the back cover. The fill plug is an 8mm allen. As you are about to remove the fill plug, fluid should start coming out, then immediately tighten.

If no fluid comes out, either it's cold or low. Use a flashlight and tip of your finger to see where the level is at, If you can't feel or see the fluid, it's too low.

Fluid should not come out the hole. The spec is 3-6mm below the hole is full.

 

[SD Rebel]

Fluid should not come out the hole. The spec is 3-6mm below the hole is full.

Is this based off cold? Everyone I checked hot always had a trickle of fluid come out. I suspect cold would be below that level.

 

[Cbty2050]

Is this based off cold? Everyone I checked hot always had a trickle of fluid come out. I suspect cold would be below that level.

Based off Ram service information. No temp is given like a transmission fluid check.

 

[SD Rebel]

Based off Ram service information. No temp is given like a transmission fluid check.

Awesome, thanks for the link. I'm gong to check it out tomorrow and try it out. I suspect when cold, it won't drizzle out at all. After a 20 mile drive, mine just barely leaked out as I unscrewed the fill plug.

What's interesting, is that a lot of the "Low" comments from RAM owners is based off of no oil coming out of the diff when they remove the fill plug. Could it be that they weren't low at all?

 

[Cbty2050]

Awesome, thanks for the link. I'm gong to check it out tomorrow and try it out. I suspect when cold, it won't drizzle out at all. After a 20 mile drive, mine just barely leaked out as I unscrewed the fill plug.

What's interesting, is that a lot of the "Low" comments from RAM owners is based off of no oil coming out of the diff when they remove the fill plug. Could it be that they weren't low at all?

Unfortunately unless they checked with the homemade dipstick they wouldn't know if it was low or not.

 

[SD Rebel]

Unfortunately unless they checked with the homemade dipstick they wouldn't know if it was low or not.

I think that is likely the case. The general rule is that the diff is full when the fluid is just dribbling out. Based on that link you provided, it's not the case on the DT RAM differential.

I don't remember a single complaint of low diff fluid was backed up with any measurement. Just that the fluid was below the fill opening.

 

[HSKR R/T]

I think that is likely the case. The general rule is that the diff is full when the fluid is just dribbling out. Based on that link you provided, it's not the case on the DT RAM differential.

I don't remember a single complaint of low diff fluid was backed up with any measurement. Just that the fluid was below the fill opening.

This is pretty common actually. The Chrysler 9.25 differential I have in my Dakota is similar in that "full" level is about 1/4" below the full plug.

 

[SD Rebel]

This is pretty common actually. The Chrysler 9.25 differential I have in my Dakota is similar in that "full" level is about 1/4" below the full plug.

That does make me think that those who complained earlier for low diff fluid were working under the more traditional assumption of filled when it reaches the fill hole.

All the other makes I've owned (non-FCA/Stallantis) were filled once the fluid reached the top of the fill hole, including all my other trucks. Just in case, I checked the instructions on the diff fill on the last 3 vehicles I've owned, they were all the same with at or just under the fill hole.

I will check mine again tomorrow, when I checked it hot, it dribbled out even before I had the fill plug out. I suspect it will be a few mm under when cold.

 

[lmike6453]

Anyone know the torque specification for the 8mm hex fill as well as the 14mm hex drain plug?

 

[mikeru82]

All the other makes I've owned (non-FCA/Stallantis) were filled once the fluid reached the top of the fill hole, including all my other trucks. Just in case, I checked the instructions on the diff fill on the last 3 vehicles I've owned, they were all the same with at or just under the fill hole.

I know you meant to say bottom of the fill hole, not the top. That has always been my practice with diffs and older manual transmissions. Good to know what it is for these trucks.

 

[wallyuwl]

Anyone know the torque specification for the 8mm hex fill as well as the 14mm hex drain plug?

I just clean the threads and use a bit if thread sealant and use the "good-n-tight enough" method with a 3/8" ratchet. You'll know when it seems tight enough, you don't need to crank on it. There also aren't a lot of threads on it, it isn't like a bolt.

https://www.amazon.com/Permatex-59235-Temperature-Thread-Sealant/dp/B000AAJTYS/ref=asc_df_B000AAJTYS/?tag=hyprod-20&linkCode=df0&hvadid=242122067968&hvpos=&hvnetw=g&hvrand=2759837869594334200&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9019412&hvtargid=pla-504163537407&psc=1

 

[Jako]

Anyone know the torque specification for the 8mm hex fill as well as the 14mm hex drain plug?

Some info on torque setting and "fluids" on the threads. Torque setting has been tossed around on one of the threads about oil changes and the oil change plug. I tend to go along with post #14 as all "contaminates" would need to be removed from the threads to set the correct number.

Reduced Torque with Lubricated Bolts

Lubrication effect on bolt tension and torque.

www.engineeringtoolbox.com

 

[Scram1500]

Well ****, filled mine to the hole, looks like I'll be draining some out. Hopefully capillary action works on 75w-140 gear oil, or siphon . Removing the drain plug for a few ounces of gear oil will be a stinky mess

 

[HSKR R/T]

Well ****, filled mine to the hole, looks like I'll be draining some out. Hopefully capillary action works on 75w-140 gear oil, or siphon . Removing the drain plug for a few ounces of gear oil will be a stinky mess

Get a turkey baster and a small piece of hose

 

[Ramroo]

Well ****, filled mine to the hole, looks like I'll be draining some out. Hopefully capillary action works on 75w-140 gear oil, or siphon . Removing the drain plug for a few ounces of gear oil will be a stinky mess

This is what I used and worked well. 60ml syringe from Amazon, and tubing from Home Depot or Lowes. I had previously filled to bottom of fill hole, so I decided to pull a little fluid. About 50 ml, almost one full syringe full worked for me, but not sure if any had vented over several months.

 

[Snotadoodge]

Assuming the dealership checks this level during the included oil changes?

 

[Ramroo]

Assuming the dealership checks this level during the included oil changes?

Never