2006 Suburban: whine under acceleration

[pacem]

177k miles 2500 suburban.

It seriously whines under acceleration and as long as under throttle. At 70, almost impossible to drive in it.

Doesnt seem to come from the engine area but from the bottom or the rear.

Gears? Transmission? What direction to look in?

 

[SirTanon]

Does the whine seem to increase in pitch in direct relation to engine RPM, or to vehicle speed?

My first thought would be transmission, but it's too early to say, given the info you've provided.

 

[EricG]

Pinion bearings!

 

[pacem]

Good question.
It gets bad after 60mph and unbearable at 70.

 

[LeakySeals]

Originally Posted By: EricG
Pinion bearings!

Yup, mine whines from front diff. Better after service. Going to try 75w140 this summer, see if that quiets it any. Noisy PS too. Leaks, needs new seals.

 

[pacem]

Approximate cost in the best / worst case scenario?

 

[zeng]

Differential is shot... likely rear's.

 

[clinebarger]

Originally Posted By: LeakySeals
Originally Posted By: EricG
Pinion bearings!

Yup, mine whines from front diff. Better after service. Going to try 75w140 this summer, see if that quiets it any. Noisy PS too. Leaks, needs new seals.


His Suburban has front axle disconnect & a part time Transfer Case unlike your AWD Escalade.

I would also check into the Pinion Bearings, If the Suburban has 4.10's.......It will whine pretty loud at 70mph, But we really need to know if the noise is engine speed, driveshaft speed, or wheel speed? A pinion bearing would be driveshaft speed.

 

[DuckRyder]

and does it make any noise on float and coast or only under power...

 

[pacem]

Only under power

 

[DuckRyder]

So does it increase only with vehicle speed or does it change with transmission shifts?

 

[pacem]

The faster it goes, the more it whines. So connected to RPMs.

 

[DuckRyder]

Originally Posted By: pacem
The faster it goes, the more it whines. So connected to RPMs.


That is contradictory...

RPM goes up then drops at each shift... vehicle speed gradually increases...

Knowing the answers to these questions helps us help you.

But if it just gets louder as the truck goes faster and doesn’t change with engine speed/shifts then the rear end is probably as good of a WAG as anything...

 

[pacem]

Well the RPMs do go up relative to speed, it is turning more at 70mph than at 50mph..

I don't know what to say, it whined like crazy at 70.

what kind of money am I looking at? Fix it or just sell it?

Are you saying all I need is a 8-lug rear?

 

[zeng]

Originally Posted By: pacem
Well the RPMs do go up relative to speed, it is turning more at 70mph than at 50mph..

I don't know what to say, it whined like crazy at 70.

what kind of money am I looking at? Fix it or just sell it?

Are you saying all I need is a 8-lug rear?


Why not drain out the olds and fill up with a GL5 80/85W-140 and see how it goes ?
Btw, is differential previously filled with a 75w90 ?

 

[pacem]

Instructions how to drain it? I was under the impression it did not have a drain plug.

 

[rubberchicken]

If the rear is shot, a rebuilt rear diff should not be that expensive, at least compared to the value of the Suburban. An aquantaince just replaced a full rear in a 2006 2500 pickup for about $1300 for the rear, he did the work himself. I have no idea how many hours of labor are required, but I think no more than 4.

 

[01rangerxl]

Originally Posted By: pacem
Instructions how to drain it? I was under the impression it did not have a drain plug.


Remove the cover to drain. The fill plug is in the front of the diff housing.

With the cover off, you will have a full view of the gears.

 

[901Memphis]

Wheel bearing?

 

[pacem]

I knew you could remove the cover, I just wondered if there was a drain plug like for oil.

Is there any possibility I am just low on oil and adding gear oil will fix it?

with the full view of the gears, I am not sure what to look for. Other than if it's empty, that's one good reason why it should whine.