Whining noise coming out from under truck...

[Michael_P]

After replacing tons of tailshaft bearings and seals, these days I just replace the entire tailshaft housing. At this point its a good time to change the rear transmission mount as well. It can be done in one hour or so and you will solve many problems at once. On a 700R4 / 4L60E, you will lose about 1/2 pint of fluid. Anyone with a socket set and a torque wrench can do it.

You can find them cheap on eBay and other online stores complete with bearing and seal.


Diff: Low pitch whine / howl
Trailshaft bearing: Higher pitch whine. Sometimes will rumble at lower speeds moreso when cold.

 

[dishdude]

Originally Posted By: jr047
The sound you describe could be from the rear axle; the loading and contact points on the gears can change when you accelerate and coast.


Yes, I always thought a whine only when on the gas usually pointed to the differential.

 

[eljefino]

Grab the rear u-joint at the diff and see if there's any play at the input to the differential. I have a ford 8.8 with a bad pinion bearing and it's 1) loud and 2) sloppy.

 

[NavyVet88]

Originally Posted By: eljefino
Grab the rear u-joint at the diff and see if there's any play at the input to the differential. I have a ford 8.8 with a bad pinion bearing and it's 1) loud and 2) sloppy.


I did this and there is no play at all front or rear.

 

[NavyVet88]

Originally Posted By: thorromig
When is the last time you changed the fluid in your rear pumpkin? I blew a rear in a 1980 Dodge Ram doing power brakes back in the day. Put a new rear in it & it made a whining noise until I added the POSI supplement. Strange but true, from there I added it once a year until I sold the truck.


This is gonna be my next course of action with the truck right after I replace the spark plugs and air filter. Can you reccomend a good diff oil? Valvoline 80w-90 is what I'm looking at.

 

[jr047]

When I changed my differential cover due to a leaking gasket (a new cover was cheap and there's a decent chance of bending the old one during removal), I used O'Reilly's house brand 80W-90, and it's been fine. I've used Pennzoil in the past, and Valvoline would be fine too. There tend to not be many selections in a parts store, so whatever's available in the right grade (probably 80W-90) will serve you well. I used a little less than 2 qts.; you may use a little more in the bigger pickup axle.

I added 8 ozs. of the GM Posi-Trac additive to mine, before adding the fluid, because I have a limit-slip differential. If you have an "open" differential, you don't need the additive.

 

[NavyVet88]

Yeah I've noticed that my local auto one and oreillys both have a very limited selection of diff oil and she doesn't drive the truck much anyway. I may go to Wally World and get the super tech gallon jug for about 12 bucks.

I just hope the parts store has the gasket seal for the pumpkin cover cuz I really don't want to use rtv

 

[mk378]

Originally Posted By: NavyVet88
Originally Posted By: eljefino
Grab the rear u-joint at the diff and see if there's any play at the input to the differential. I have a ford 8.8 with a bad pinion bearing and it's 1) loud and 2) sloppy.


I did this and there is no play at all front or rear.

It should be noted that this test needs to be done with the transmission in Neutral, not Park. In Park, the driveline may be under stress holding the truck still, and this will pull all of the slack out of loose components.

Before getting underneath a truck that is in Neutral, of course you want to be on level ground with the brake set and the wheels chocked so it can't roll over you. The engine does not need to be running, it is safer if it is not.

 

[NavyVet88]

Originally Posted By: mk378
Originally Posted By: NavyVet88
Originally Posted By: eljefino
Grab the rear u-joint at the diff and see if there's any play at the input to the differential. I have a ford 8.8 with a bad pinion bearing and it's 1) loud and 2) sloppy.


I did this and there is no play at all front or rear.

It should be noted that this test needs to be done with the transmission in Neutral, not Park. In Park, the driveline may be under stress holding the truck still, and this will pull all of the slack out of loose components.

Before getting underneath a truck that is in Neutral, of course you want to be on level ground with the brake set and the wheels chocked so it can't roll over you. The engine does not need to be running, it is safer if it is not.


Of course my good man

 

[Srt20]

Originally Posted By: mk378
Originally Posted By: NavyVet88
Originally Posted By: eljefino
Grab the rear u-joint at the diff and see if there's any play at the input to the differential. I have a ford 8.8 with a bad pinion bearing and it's 1) loud and 2) sloppy.


I did this and there is no play at all front or rear.

It should be noted that this test needs to be done with the transmission in Neutral, not Park. In Park, the driveline may be under stress holding the truck still, and this will pull all of the slack out of loose components.

Before getting underneath a truck that is in Neutral, of course you want to be on level ground with the brake set and the wheels chocked so it can't roll over you. The engine does not need to be running, it is safer if it is not.


X2

Sounds like pinion bearings to me .

 

[philipp10]

Originally Posted By: NavyVet88
Originally Posted By: jr047
From that description I wonder if a bearing is starting to go bad, possibly in the rear axle. Hopefully someone who's encountered something like that will chime in. It sounds like the rear axle may never have had its fluid changed, and it might be worth having a transmission or axle shop look at it.


Yeah my thoughts as well. Regardless of the sound, the tranny is gotta get fixed for the leak and I'll be sure to inquire about the noise. And as I'm typing this, she tells me that sound has been present for years smh


if its been present for years why bother messing with it? The vehicle has 208k miles....

 

[ls1mike]

Reminds me of when the carrier bearing went out in my old 71 K5 Blazer.

 

[Michael_P]

Diff carrier bearings may not have any wiggle as the galling process tightens (and roughens) things up.

 

[NavyVet88]

Originally Posted By: philipp10
Originally Posted By: NavyVet88
Originally Posted By: jr047
From that description I wonder if a bearing is starting to go bad, possibly in the rear axle. Hopefully someone who's encountered something like that will chime in. It sounds like the rear axle may never have had its fluid changed, and it might be worth having a transmission or axle shop look at it.


Yeah my thoughts as well. Regardless of the sound, the tranny is gotta get fixed for the leak and I'll be sure to inquire about the noise. And as I'm typing this, she tells me that sound has been present for years smh


if its been present for years why bother messing with it? The vehicle has 208k miles....


I somewhat share the same thought on this situation because almost any repair over 5-800 bucks is gonna be more than the truck is worth at this point but I would love to know that this truck could put out for another 100k miles