Rear differential a bit noisy

I bought this 2011 for my son with 217k. Prior owner, bought it a year before at 198k said he changed all of the fluids when he got it. Could the differential be noisy because maybe the fluid level is low or maybe the fluid is no good? I always liked Mobil 1 fluid, so is their 75w90 okay even if the manual calls for 75w85?

 

Your not gona hurt anything running

$29 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90, if it's making noise because the fluid is low or contaminated damage has likely already been done.
Are you sure it's coming from the differential and it's not a rear axle bearing?

 

Like Dm93 said, you’ll be fine with

$29 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90

I literally just checked my fluid level today.
I’ll go ahead and warn you, use a 6 point socket on the fill plug.
The bolt head is thin and soft. The fill plug torques to 36 ft/lb. (Or good and tight)

I don’t remember what the drain plug torques to? It’s been awhile since I did it.

 

Thank you. The sound gets louder when I let off of the pedal. I changed the center bearing which was really worn but it only decreased the noise by 50%. Depending on the load, on the pedal or off the pedal, the noise can go away or get louder. I think it was the axle bearing, wouldn’t it be the same sound regardless of on or off the pedal? Is the axle bearing like wheel bearings you mean or is that inside the diff?

 

The axle bearing is the wheel bearing.
It’s bolted to the axle housing behind the rear drum.
If you look at the backside of the rear drum, you’ll see 4 nuts. They hold the axle/bearing to the axle housing.

But you can’t just unbolt it. The bearing is also pressed onto the axle shaft.
It’s a PITA.

 

Axle bearings are mounted on the ends of the axles behind the brake backing plates, I agree if it was axle bearings the noise should be consistent regardless of load.
Sounds like you may have a pinion bearing that is failing, I would drain the fluid and see what it looks like and check for play in the yoke on the diff.

 

Can the pinion bearing be changed fairly easily or does this mean a new differential?

 

The differential needs to come apart.
And then be set up properly when put back together.

Unless you know how, and have the right equipment, it would be better to buy a drop-in 3rd member.
However, I’d be certain of what the problem is before ordering a differential.

 

It can be done if that's what it is but it's not a simple task, you have to know how to set up gears, clearances and preload on bearings.

That kind of stuff is beyond my skill area, I could probably do it if I had to but it's not really something I would want to get into.

It's probably something that’s best left to a shop that does differential work or find a good used or rebuilt unit.

 

These guys are really well know for building quality diffs.
But again, make sure that’s you problem.

Drop-in 3rd member.
https://eastcoastgearsupply.com/c-1065072-assembled-3rds-clamshells-05-15-tacoma.html

 

Thank you

 

How noisy is it?
I’ve seen differentials go a long time with a noise.

Should you? Probably not, but it’s all coming apart anyways.

Obviously this isn’t good advice, but a noisy diff can just be noisy for a long time.

 

It's not too bad but annoying to me coming from my lexus. I just changed the center bearing and that helped by 50%.

 

I think I'd drain the fluid on it and see what it looks like, if it's not full of glitter or metal chunks you may have some time yet but if it's shiny or there's chunks in it it's done.

 

Thank you, and if it's done, what do I do next? Do I buy an entire rear end assembly or do I buy a used a differential? How much would a shop charge for install do you think?

 

With 217k, you could probably get by with a lower mileage used unit.

Me on the other hand, I would end up with a bad used diff. Because that’s how my luck goes.

Just be sure it’s from a 2009+truck.
Don’t get one with the mechanical LSD.

If you have the rear locker, any year model should work.

 

You will have to get some prices (used vs rebuild) and weigh your options, shop prices will vary greatly depending on region.

 

I changed the fluid, it looked like there was fine particles in like like I was panning for gold. I also had a smidge of up and down play on the part of the diff that bolts to the driveshaft, I guess that’s the yoke? I tightened that center but a tiny bit and got rid of the plymay. Overall, the noise has reduced some but it’s still there. So does that sound I will need a new diff, or a used one or a rebuild? It’s operating okay, but annoying to me to know the sound is there when I left off the gas and the load on the driveshaft changes. It sounds like “shhhhhhhhh” when I left off the gas at around 20-50mph.

 

Yea sounds like you have a failing pinion bearing, it may go a little while yet but it may not.
Like I said earlier you will have to price out, weigh your options, and see what works for you as far as used vs rebuilt vs having someone rebuild. But it would be a good idea to start budgeting for it either way because it's almost certainly not gona get any better.

 

100% pinion. call ecgs. they told me 7 a week fail in the u.s. I tried to figure it out for a long time, drove me nuts. The day I put the new 3rd in and drove down the road in complete silence was amazing .