Redline gear oil issue?

[bassheadhemi]

Last weekend, I changed my diff and tcase fluid with Redline fluid. Since, the rear diff is making a humming noise (sound like tire noise).

Truck have 3.92 with limited slip
I've use the Red Line 75w140 (Not the NS one)
I've check the level and it's fine
Jacked up the rear and was able to reproduce the noise with the wheel off the ground so it's not the tires

Anyone ever had issue with Red Line 75w140 in their diff?

There was 0 noise before the fluid change

 

[Elevated 2013]

I have Redline in all of my driveline (transmission, transfer case, and the front and rear diffs) and I have zero issues with them. Could it have been there before the fluid change? When you drained the old fluid was there and metal shavings in it? Did you take the diff cover off and inspect the gears??


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[bassheadhemi]

positive the noise wasn't there before

the fluid came out greyish, but from what I understand this is normal for the first service. I've look in the pan after dropping my 14mm hex in it and I didn't noticed any shaving.

I didn't remove the cover, just did a dump from the drain plug and filled it back.not sure if I want to remove the cover just yet, maybe adding more friction modifier could help? but doubt it since there's no binding when turning

I did about a dozen figure 8 at low speed in a parking lot without issue. the noise start to appear when I pick up some speed

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[Elevated 2013]

Grayish is about right. How many miles on the truck? Have you tried moving the pinion shaft at all front to back to check for play there? Can you tell it’s coming from inside the differential housing for sure?? I know you ruled out it being tire him but humming is kind of odd from a differential unless the pinion is not riding in the normal spot on the ring gear. I’d much rather try to rule out a u joint in the driveshaft or something more that could just be transferring the noise to the differential. Just kind of odd a fluid change would bring this on. Redline already has a pretty good friction modifier in it. You can try adding a little more if you have some sitting around. I can’t see it hurting anything. Hopefully someone else might chime in with an idea.


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[ramsare4real]

Following...fixing to RL my rear diff too.

 

[Hemi395]

Following. I've been running RL gear oil in both my diffs and both diffs are nice and quiet. This is the first I've heard of RL gear oil being a problem.

Can you get a video of the noise?

 

[dexter]

In my Dodge Dakota I used Mobile 1 and the gears became nosier.

The Mobile 1 might have been thinner then what I used before.

I added more friction modifier and the noise went away.

 

[bassheadhemi]

truck have 48k miles

here's a video of the sound


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[Tim Garceau]

The existing fluid was muffling the carrier and your new fluid is too thin. Does the noise change as it warms up?

If it’s a howl usually ring and pinion related.

 

[bassheadhemi]

The existing fluid was muffling the carrier and your new fluid is too thin. Does the noise change as it warms up?

If it’s a howl usually ring and pinion related.

no the sound doesn't change as it warm up, the video i did was after sitting overnight and was 50 when I recorded

75w140 can't be too thin?

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[madtrucker2016]

With that high level of disturbing noise ,I would open the rear hatch to get a look see. Maybe a axle is going. Plan a day for this it will not be quick and maybe a friend could help you.

 

[Elevated 2013]

Sounds like a ring and pinion howl that was masked by the old oil. No way 140 is too thin as it’s the thickest I know of. I’d take the cover off and look at the wear pattern on the ring and check for damage to both gears.


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[ram1500rsm]

I'm affraid the issue is not with the fluid although it's also interesting you didn't have any noises before. Could it be possible your rear diff tolerances are a bit tighter than normal?. Like others are saying only way to know what's going on is to pop the diff cover and take a look inside the diff.
If everything checks out ok knocking on wood you can try Torco RGO 85w140 and a bottle of Mopar FM.

Good luck.

 

[Tim Garceau]

Video sounds like pinion bearing, however check your e-brake and does the sound continue if you shift into neutral while driving?

 

[Burla]

Did it happen the second of the fluid change? As in the very first trip and it was noticable?

 

[Burla]

When you drained the diffs were they warm? And how long has this been going on? Have you taken a lot of left and right turns? Bottom line it isn't being lubricated adequately. If it continues, you have to drain it and refill presumably with something else. Sounds as if the redline is TOO thick and may not be lubricating the axle.

First I would add some modifier, if that fixes it this will be the first documented case where it was needed. Maybe this will or will not help, yes usually for chatter but I'd put it in at this point.

Taking cover off would also be a good idea. Something redline is known for is hype cleaning, so that's why it is important to know if it happened first trip, if so this wouldn't be likely cause.

 

[bassheadhemi]

ok so the cover is off

first thing I noticed is the enormous amount of rtv that was use, is it like this from factory?

next is that it look like the redline was cleaning the housing pretty heavily as it came out very grayish and you can see spot in the cover where risidue was getting cleaned.

so far everything look normal and no metal shaving came out except for what appears to be fine metal dust in the oil.

I didn't drove the truck right after doing the fluid swap, I simply back off the driveway and park it in the street. I noticed the noise 2 days later when I was bringing my daughter to school, then I left for a 600 miles trip where i would notice the noise from 10 to 40mph and then the road noise would mask it. came back and parked it since

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[Elevated 2013]

Maybe it’s just me but it looks like the ring gear either has some dirty teeth or damage on them based on the 3rd or 6th picture. What does anyone else think??


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[bassheadhemi]

dammit found something

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[Elevated 2013]

With only 48k l, depending on the year of the truck, that might be covered by the drivetrain warranty??


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