Pinion Bearing Went Out

Tony Conti

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I simply told him that I replaced the rear wheel bearings and seals and that the noise is a humming/howling noise that increases the pitch of the noise the faster you go. He didn't test drive it or actually diagnose anything. I'm not trying to discredit or offend anyone on the forum that's trying to help.
 

RED09GT

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It could be contamination or damage from when you pulled the axles to change the rear wheel bearings.
If you haven't done gears yet but want to, it would be a good time to do them as you'll have to do 90% of the gear swap in order to change the pinion bearing.
 

Tony Conti

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It could be contamination or damage from when you pulled the axles to change the rear wheel bearings.
If you haven't done gears yet but want to, it would be a good time to do them as you'll have to do 90% of the gear swap in order to change the pinion bearing.

Yeah I'm thinking about just doing that and putting a different LSD in it. I'm going to put the stock wheels back on and see if it actually makes a difference. At work today we put it up on a lift (only had about 15-20 min) and with me in it the tech had me take it to 20,40 and 60mph while he was listening to the rear end with a screwdriver on the area the pinion bearing is. He said he didn't hear anything unusual going on (this is a different guy that I trust and told me to bring it in the shop to look at it instead of telling me what it might be.) Like I said we didn't have much time. Parked it back outside and tomorrow after work when I have some time I'll put the stock wheels back on and drive it.
 

Sky Render

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Put an Eaton TrueTrac in there along with some new bearings and oil while you're at it. While the axle is apart, you should do the axle bearings and seals, too.

Any way you can take a video of the sound? Maybe have someone sit in the back seat and record it?
 

Tony Conti

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That a good idea on the video, and for the Eaton TrueTrac I just looked it up and it looks solid, has a 10 year warranty too which is nice.
 

Pentalab

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The Eaton TrueTrac is probably the best all-around differential. Good price, good performance, very sturdy, and minimal maintenance.

Here's some reading for you:
https://motoiq.com/project-grey-mustang-5-0-part-5-putting-the-power-down-with-eaton/
For street car and general all round use, the Eaton Tru trac is a rock solid LSD. If folks are planning to swap out the UCA, at least put one in that can have it's length adjusted.... the difference in price is minimal. You are just delaying the inevitable. (removing the non adjustable uca, then replacing with an adjustable uca). Just do it right the 1st time.
 

Norm Peterson

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Its a non adjustable arm.

Here's a pic of the arm.

Torqued fully when car was in the air.

Thanks for not being a smartass.

View attachment 74928
The polyurethane end doesn't care whether it's torqued with the car's full weight on the wheels or if the axle is hanging free.

But the OE rubber axle-side bushing does care, and that's what you should inspect. I have no idea what it might take to fail the axle-side UCA bushing, but I would imagine that more noise would be one consequence. Plus, the firmer body-side poly bushing will allow more axle noise (gears, bearing, tire) to come through into the cabin.


Norm
 

Norm Peterson

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The Eaton TrueTrac is probably the best all-around differential. Good price, good performance, very sturdy, and minimal maintenance.

Here's some reading for you:
https://motoiq.com/project-grey-mustang-5-0-part-5-putting-the-power-down-with-eaton/
Wish I could figure out what the compromise is as the bias ratio goes up. Obviously a bigger bias ratio is what you'd want for a more powerful engine in a performance environment. Just wondering what you might be giving up to get that.


Norm
 

Pentalab

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Wish I could figure out what the compromise is as the bias ratio goes up. Obviously a bigger bias ratio is what you'd want for a more powerful engine in a performance environment. Just wondering what you might be giving up to get that.


Norm
Compared to the oem clutch packs... you are giving up nothing. I used 75W-140 in mine. I had the whiteline watts link installed at the same time as the tru-trac. That combo is night and day difference to oem.
 

Sky Render

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Wish I could figure out what the compromise is as the bias ratio goes up. Obviously a bigger bias ratio is what you'd want for a more powerful engine in a performance environment. Just wondering what you might be giving up to get that.


Norm

Noise, cost, and potentially reliability. Eaton TrueTrac is 3.5:1. Torsen T2-R is 4.0:1 and double the cost. Torsen doesn't like hard launches, either.
 

Tony Conti

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Took these pictures last night when I took the wheels off. The first pic has the most visible damage. Put the stock wheels on (front) that had firehawk Indy 500's on them and 90% of the noise went away... The howling/vibration has gone away and there is just a noticeable high pitch whining that I can only hear around 60mph that is coming from the rear. Its not very loud but it is noticeable. I've never heard a noise like that coming from tires so I am still pretty shocked. $700 lesson I'm not too happy about. But as far as the high pitch whining goes I don't know if its been there and I don't know if I just now noticed it because I was paranoid about the pinion bearing potentially going out. What sucks though is that where I'm at in Ohio the salt is about to be laid down soon so I don't have much driving time left.

If anyone has links to those s197 suspension articles I would appreciate it if you posted them cause I would like to set up the suspension correctly.

And lastly I want to try some autocross next year and I was wondering if I should get new tires or just run these? I don't know if I've compromised the performance of the tire to the point of them being useless. They only have around 1000 miles on them and they're 100 tread ware grade tires.


TIRE.jpg

TIRE2.jpg
 
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Juice

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I'd run those without worry at a track day.
 

Norm Peterson

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Noise, cost, and potentially reliability.
Not the information I'm looking for. Ford has chosen to use differentials with quite a wide range in torque bias ratio, so there has to be something attractive about the lower bias ratios. There must be a reason why the Boss gets a 2.7 TBR, and the 'street' (Track Pack?) gets the 2.0 unit.


Eaton TrueTrac is 3.5:1. Torsen T2-R is 4.0:1 and double the cost. Torsen doesn't like hard launches, either.
Cost kind of is what it is, assuming that you can get away with only buying it once. I'm thinking that lower-powered cars, like stockish 4.6s and V6s, shouldn't need as much TBR as a 5.0 or forced-induction 4.6/sixxer, and I'm looking for what might be better about the lower TBRs.

For me personally, hard launching, wheel hop, and tire-chirping upshifts are things I just don't subject my cars to. Hard cornering in the wet at a track day very definitely is a consideration (which would amount to additional margin on the street against poo happening in a wet corner there).


Norm
 

Pentalab

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The Torsen, in any TBR, is a poor investment vs the Tru-trac. For real high powered applications, (and $150.00 more) eaton makes the tru-trac with 4 x side gears per side ( vs 3). Typ used used on the strip, when the 60' times are down to 1.4 secs. The standard tru-trac, with the 3 x side gears per side, is ample for 90% of the street /autocross/strip / road course applications. Plug and play, use 75W-140 dino oil...and end of issues...and no differential heat issues either.

The higher bias ratio's come in handy for autocross, where the car has to do a 180 deg...or a sharp 90 deg etc.
 

Norm Peterson

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The higher bias ratio's come in handy for autocross, where the car has to do a 180 deg...or a sharp 90 deg etc.
Understood. But I have a really hard time believing that there aren't driving or car setup situations where a lower TBR has some advantage. Otherwise, the Boss Mustangs would have been given a 4.0 Torsen instead of the 2.7.


Norm
 

BottleRocket

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There is also the possibility that the timing of the noise could have just been coincidental. My 1st '08 (I've had 3) sat at stock height and the pinion bearing went out - 3 times, all within 20-30K miles. I tracked it once or twice a month but I ran stock tires exclusively. I even had my local Ford dealer look for 8.8-service related bulletins but he never found anything. Personally I believe it's either a bad run of differential housings or maybe a bad run of bearings but I have no proof. Good luck with that.Richards_GT.jpeg
 

Anti

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I am about to pull the trigger on either a torsen, trutrac, or, slim chance, detroit locker (or whatever it is called.)

The thing that kept me from snatching up the trutrac last night was hearing of its 500hp limit. Anyone else read on this? Also, I only found one on Amazon. They are still make my these things new, right?
 

Pentalab

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I am about to pull the trigger on either a torsen, trutrac, or, slim chance, detroit locker (or whatever it is called.)

The thing that kept me from snatching up the trutrac last night was hearing of its 500hp limit. Anyone else read on this? Also, I only found one on Amazon. They are still make my these things new, right?
Never heard of a 500 hp limit, that's a new one for me.
 

RED09GT

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Do you have a source for the 500 hp limit? Lots of cars out there with double that and not many failures-including many in 4000lb+ cars.
 

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