Rear differential whine at 30-40 MPH '14 RAM 1500

[pb379]

I have a slight whine-howl type of noise from what I think is the rear differential. Maybe a rear wheel bearing or pinion bearing? I think it could also be the drive shaft carrier bearing but not sure.
2014 RAM 1500 EcoDiesel
3.92 Limited Slip
156,100 miles
I changed the gear oil in it yesterday. The fluid was black and stunk like hell but I didn't see any alarming chunks. I strained the used oil through a paint strained funnel. Nothing alarming. I took a sample to send to OAI. The fluid was last changed at 46,000 miles so this fluid had over 100k miles on it with about 40% of those miles towing a 6,000lb Airstream travel trailer. I used Valvoline SynPower 75W-140 when I changed the FF at 46k miles back in 2016. I just realized today that I mistakenly bought a bag of 75W-90 along with the 75W-140. So right now I have franken brew. I'm going to drive it enough to get it hot and drain and refill with the correct 75W-1140 Valvoline gear oil.

Anyway-make sure you have the correct viscosity when buying this Valvoline gear oil at Walmart.

 

[Lubener]

I seroiusly doubt your frankenbrew would cause any problems with your differential.

 

[pb379]

You're probably correct. I just want it uniform so when I sample again I know what to expect-sort of.

I seroiusly doubt your frankenbrew would cause any problems with your differential.

 

[johnmyster]

What are we expecting UOA to tell us?

Doubt the whine is because the fluid isn't holding up. The BITOG mantra on UOA is it doesn't tell us wear rates.

 

[50yr Street Mech]

I'm no differential expert, but towing 6,000lbs for 40% of 156k is quite a lot. Then you mentioned the fluid was black and stunk like hell. Sounds like overheating to me. Gets hot it Texas too, that don't help matters. Something in there got fried. Exactly what, I don't know. Maybe do a stethoscope job on it to narrow the area down.

 

[pb379]

What are we expecting UOA to tell us?

Doubt the whine is because the fluid isn't holding up. The BITOG mantra on UOA is it doesn't tell us wear rates.

Just general information about how good or bad the fluid is after being treated like crap.

 

[pb379]

I'm no differential expert, but towing 6,000lbs for 40% of 156k is quite a lot. Then you mentioned the fluid was black and stunk like hell. Sounds like overheating to me. Gets hot it Texas too, that don't help matters. Something in there got fried. Exactly what, I don't know. Maybe do a stethoscope job on it to narrow the area down.

Yeah maybe I should pop the cover off.

 

[50yr Street Mech]

I wouldn't do that yet, jack it up, jack stand it,put it in drive, and do the stethoscope thingy on it. It will point you in a direction to where the problem is. Piece of wood from the axle to you're ear in different locations usually works, or a wooden hammer with the hammer part to you're ear, a screwdriver with the handle to you're ear.

 

[D60]

Did these still just get the Corporate 9.25? @OVERKILL probably knows

 

[pb379]

Did these still just get the Corporate 9.25? @OVERKILL probably knows

I’m not certain. I have never read of a rear differential shiddabed on the 1500 eco diesel forum. Even the guy who used his to deliver Airstreams from the factory for several hundred thousand miles.

 

[pb379]

I wouldn't do that yet, jack it up, jack stand it,put it in drive, and do the stethoscope thingy on it. It will point you in a direction to where the problem is. Piece of wood from the axle to you're ear in different locations usually works, or a wooden hammer with the hammer part to you're ear, a screwdriver with the handle to you're ear.

That’s good advice thank you. They make it really hard to do that with the safety stuff on these modern machines. When you open the door and the truck isn’t moving it shifts to Park. I guess I’ll have to find a helper. Maybe I can get it to work with a broomstick to push on the brake and turn the shifter through the window.

 

[pb379]

Did these still just get the Corporate 9.25? @OVERKILL probably knows

Looking it up grok says it a 9.25 ZF rear end.

 

[Slick3914]

I'm no differential expert, but towing 6,000lbs for 40% of 156k is quite a lot. Then you mentioned the fluid was black and stunk like hell. Sounds like overheating to me. Gets hot it Texas too, that don't help matters. Something in there got fried. Exactly what, I don't know. Maybe do a stethoscope job on it to narrow the area down.

I would have changed at 30,000 intervals when towing.

 

[Nuclear_42]

100K is way too much especially for that amount of towing. 50-60k seems more reasonable if interested in less maintenance. However given the towing aspect 30-40k is probably a better choice. Gear oils much cheaper than any diff repair job. Lets see how the oil sample looks.

 

[pb379]

100K is way too much especially for that amount of towing. 50-60k seems more reasonable if interested in less maintenance. However given the towing aspect 30-40k is probably a better choice. Gear oils much cheaper than any diff repair job. Lets see how the oil sample looks.

Yeah you’re right. I don’t know how I let it go this far but I did. It isn’t hard to do or expensive. I just wasn’t on top of it.

 

[50yr Street Mech]

Keep us posted as to what you find out....

 

[OVERKILL]

Did these still just get the Corporate 9.25? @OVERKILL probably knows

There was the Corporate 9.25 and then they moved to a ZF 9.25, but there is also the Dana axle that was used in the trucks with the HD tow package. IIRC, it was somewhere around 2016 that they moved to the ZF unit? @The Critic and I were talking about this recently off-forum.

 

[Drifter]

That’s good advice thank you. They make it really hard to do that with the safety stuff on these modern machines. When you open the door and the truck isn’t moving it shifts to Park. I guess I’ll have to find a helper. Maybe I can get it to work with a broomstick to push on the brake and turn the shifter through the window.

Get a helper. The broomstick etc might work in a pinch but..... And let us know the findings. Good luck

 

[meep]

I’ve had several vehicles with diff whine. The only one where I felt was acceptable was a Jeep GC with 230k on it. However, my 2018 F150 developed it in its second year, no change with new fluid. We towed a TT with it from day 1 but only a couple thousand miles a year maybe. It was first only in the cold and then most of the time until it was good and hot. It sort of settled in and stopped getting worse. Believe it or not, my 2024 Tacoma has a very small amount. I had an old Chevy sedan that had it badly after being rear-ended, but after several years of driving it really didn’t get worse, so just drove it and changed the fluid more often.

 

[Nuclear_42]

I’ve had several vehicles with diff whine. The only one where I felt was acceptable was a Jeep GC with 230k on it. However, my 2018 F150 developed it in its second year, no change with new fluid. We towed a TT with it from day 1 but only a couple thousand miles a year maybe. It was first only in the cold and then most of the time until it was good and hot. It sort of settled in and stopped getting worse. Believe it or not, my 2024 Tacoma has a very small amount. I had an old Chevy sedan that had it badly after being rear-ended, but after several years of driving it really didn’t get worse, so just drove it and changed the fluid more often.

My 24 1500 Sierra had a slight white when front axle was engaged. Recently switches to Amsoil Severe gear 75w-90 and it's gone. It could be the ad pack in the oem fluid.