[AT] Getting water out of a gearbox/now bearing life

[charlie hill]

True enough I guess Steve.  Also the folks at GM have no interest in me 
keeping my truck for 20 years and putting 500,000 miles on it.
Statistically, folks like me are way beyond an anomaly.   Still it would be
nice and at 10 times 2 bucks or even 100 times 2 bucks it would be an
interesting gadget to have. It would not have to read the actual bearing 
race temperature.  All it would need to do is read the extremes at the
location of the zero speed sensor and report an out of range event that
would reset if it was short term.

Charlie

-----Original Message----- 
From: Stephen Offiler 
Sent: Friday, June 05, 2015 9:18 AM 
To: Antique tractor email discussion group 
Subject: Re: [AT] Getting water out of a gearbox/now bearing life 

On Fri, Jun 5, 2015 at 7:30 AM, charlie hill <charliehill at embarqmail.com>
wrote:

> You know, it just occurred to me regarding what I wrote below,
> That hub assembly already has a zero speed sensor built into
> it.  Surely it would not have been too hard for GM's engineers to
> put a high temperature alarm in there two.  I guess it would have
> cost them a dollar or two.  With the price of a new truck comparable
> to my '06 now being in excess of $50,000 you would think they could
> afford to throw it in though.  Then again maybe the 2015's have that
> feature?
>
> Charlie
>
>
Nobody offers this feature as far as I know, and I'll acknowledge it is a
REALLY interesting idea, but the devil is in the details.

The system cost (temperature detection device, its mounting and sealing
within the bearing assembly, plus the wiring, plus the hardware components
and some software to interpret the signal inside a computer somewhere) is
potentially quite a bit greater than the $1-2 you suggest.  Ten times that
figure would not surprise me even a little bit.

But I think the real issue is statistics.  Somebody at GM, I can *assure*
you this is a fact, has done a Design Failure Modes and Effects Analysis
(DFMEA) on those bearings as well as every single other piece of the
truck.  They consider the likelihood of failure within a certain mileage or
timeframe (often 150,000 miles)  and they consider the negative effects of
a failure.  They rank every single component and system on the entire truck
and put the vast majority of time and effort into knocking down the most
likely failures with the most severe consequences.  I've worked for a major
automotive supplier in the past, and part of my job was creating and
maintaining DFMEA documents for the components we manufactured, so I know
exactly what I am talking about here.

In short, I am certain that those hubs/bearings have been the subject of a
DFMEA and they fell way back behind many other possible failure points and
got lost.  So no money, zero point zero dollars, allocated for your
temperature sensors.

SO
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