[alfa] Follow Up: Is this transmission toast? (longish)

[Kevin Trent <trentkc@xxxxxxxxxxxxxx>]

ORIGINAL QUESTION:

> Date: Mon, 21 Jun 2004 23:59:08 -0400
> To: alfa@domain.elided
> From: Kevin Trent <trentkc@domain.elided>
> Subject: Is this transmission toast?
>
> This past Sunday I drove my '73 spider to a bike race 190 miles away.  I 
> got a late start and had to drive fast (got there in 2.5 hours) and with 
> two bikes on the trunk and the top town, it was pretty noisy on the 
> interstate at 80. This drive was early, at 7am and the temperatures were 
> cool and the car ran fine.  But in the heat of late afternoon on the 
> return trip the car began to make an unholy sound from the transmission - 
> the sound of a screeching bearing going bad.  I nursed the car back home, 
> with the trans having the bearing screech come and go as I drove the on 
> the interstate and adjusting speed to eliminate or minimize the 
> transmission sound.  At times smoke would emit from the shift boot, and if 
> the screech got real bad (it came and went with varying degrees of 
> severity), I could feel the car slow as if I had pulled on the emergency brake.
>
> But I made the 190 miles home.  The trans felt hot, but nothing I could 
> really point to as abnormal and it didn't stink of hot burned 
> oil.  Tonight I drained the trans oil and only got about a half quart to 
> come out.  I did not see any obvious amount of metal in the oil. The 
> magnetic drain plug did not have an unusual amount of metal on it, but  I 
> stuck my finger into the drain and wiped it around (it felt "gritty"), and 
> when I wiped off there was obviously metal flakes from this bottom 
> sludge.  Unfortunately, I was unable to drain the trans when it was hot, 
> so I'm not sure if metal residue just settled in the bottom of the trans 
> rather than draining out with the oil.
>
> SO it appears that I drove the car too far and too long and too hard with 
> too little transmission oil, and a bearing has gone bad.  What to do?
>
> My initial thought is to refill the transmission with 30 or 40 (or?) 
> weight oil and do a little test driving to ascertain (a) if the proper 
> amount of oil will eliminate the bearing noise and (b) if this thin oil 
> will wash out the metal residue from the transmission.  If the noise is 
> eliminated, I'll drain the thin oil and replace with proper gear lube and 
> just drive it.
>
> Or is this just wishful thinking, and the transmission has been ruined, 
> and I might as well just replace or rebuild it?
>
> Opinions or experiences with such situations?
>
> thanks, //kct, Powell, TN
RESPONSES (from the digest):

Yep, burned to a crisp.

~~~~~~~~~~~~~

What happened is that one of the bronze bushes between one of the gears and
the main shaft tried to seize to the main shaft due to lack of oil. Thus
the noise and the feeling of 'drag'. (If it had fully seized, the tranny
would have been essentially trying to be in two gears at once--fifth, which
you had engaged, and the one that was trying to seize, and thus locked
solid, unable to turn at all.)

It is most likely that it was either first or second gear that tried to
seize to the mainshaft, as these have the greatest speed differential
relative to the main shaft when in fifth gear.

There is a LOT of heat involved when this happens. It wouldn't be too
surprising if both the main shaft (pretty likely) and the gear involved
(less likely) are toast.

The strength of the main shaft is likely compromised due to softening from
the heat.

Fill it with oil and baby it for as long as you must, but plan on
rebuilding it with some parts needed pretty soon.

#2 diesel makes a GREAT flush for a tranny. Get it reasonably warm, drain,
fill with diesel, start the engine and simply let it idle for a bit (no
driving) . Then drain and refill with the proper gear lube.

In my 'experience' (don't ask !!), a leak out of the inner shift boot is
NOT uncommon. The little O-rings that seal the shift rails at the front are
another source of dribble that is sometimes missed when rebuilding--

~~~~~~~~~~~~~~~~~~

You have nothing to lose at this point. Fill the tranny with Spirax and
drive it. If things settle down and the noise goes away drain the tranny
(get it hot first) and refill. If the noise does not go away then you
probably fried one of the bearings and need a rebuild. Once these trannys
are smoked its better to get a good core and rebuild it rather than
spending a lot of money trying to salvage an overheated tranny. Cores
should run about $250, You will spend more than that on new bushings in
the old tranny if they are cooked.

~~~~~~~~~~~~~~~~~~~~~

My Super had almost exactly these symptoms back in 1979, and I had a 50-mile
drive home, carpooling with students from college.  It wouldn't screech in
fourth gear, but did in all the others.  It turned out I ran low on oil, and
it ruined one of the gear bushings on the main shaft, second I think.  I
gave the trans to a Alfa mechanic, who replaced just that bushing, and put
it all back together for $80.  I drove that trans with no further problems
til 1994.  So maybe it's just a bushing?

~~~~~~~~~~~~~~~~~~~~~~

I had a similar experience, but did not drive as far after in my 67 GTV. I
refilled the transmission 10K miles ago and it has been fine. Try that
first. Good Luck...
|
~~~~~~~~~~~~~~~~~~~~~~~~~

I would refill and try it.

I have had a Fiat transaxle completly seize up running 70mph and twist me 
around in the road.. Let it cool down.. fill with oil and run another 50K 
miles with no one bit of trouble.

It could be the center drive shaft bearing that is squeeling and creating 
heat, and not your tranny.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Its not good to run a diff without EP lubricants and I would not use a
30 or 40 wt engine oil. Flushing with light oil may be ok.
One thing you could try is EP lube with moly which seems to cure a lot
of problems due to excessive friction because Molybdenum Sulfide has the
ability to bond to ferrous surfaces. Its worth a try but you may find
that a strip and rebuild is what is eventually needed.

What I can't understand is why the oil wasn't stinking hot when you got
home. Perhaps you did an extra good job of nursing it. I have changed
diff oil when it has been boiling as it came out but this was in a
racing GTV6.

Someone else may have some other suggestions that are more helpful; if
not, try the moly.

~~~~~~~~~~~~~~~~~~~~~~~~

Kevin - If that transmission was screaming in pain and smokin', I say it's a
safe bet that it's a goner.
I suppose you could try to send it out for rebuild, but if the gears or
shafts themselves are damaged, it probably will be VERY expensive to
overhaul. You won't know until you open it up. I sure wouldn't drive it
anymore. BTW, oil capacity is 3.8 pints. Good luck.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

WHAT I DID:

I refilled the transmission with a quart of EP gearlube and topped off with 
nearly a quart of 50w engine oil.  Upon startup, the horrible screeching 
bearing noise was gone, but there was a bit of transmission whine in 
neutral, first and second.  I went for a drive last Saturday morning to do 
my drive-around chores and the transmission worked fine, with no 
reoccurrence of the bearing screech, about 30 miles.  In fact, it worked so 
well that my son and I decided to drive it up to a bike race in North 
Carolina later that afternoon.  So we loaded up with two bikes and us 
Clydesdale size riders and drove US129 (the "Dragon tail" - bikers out 
there know it) over the mountain to Font ana.

Bottom line:  I lucked out.  I've put on 300 miles and the transmission 
whine has largely subsided.  It shifts fine and makes no unusual 
noises.  Next time I get it hot, I'll drain the "flush" oil that is in it, 
and refill with Spirax.

Thanks once again to the digest and those who kindly responded!   //kct, 
Powell TN
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