The Mystery of the Rotating Bearing!

STREET SMART

The Mystery of
the Rotating by Mike Brown
members.atra.com

Bearing! Toyota U660E shift problems traced

back to case wear and damage; the
fix requires replacing the case.

Figure 1

T
here are days when you spend models in the U.S. over the next four plaints: harsh or erratic shifts, engage-
lots of time investigating prob- years: ment problems, and converter clutch
lems only to come up short or • RX350 2010-13 issues. All of the transmissions were
the trail runs dry. Today we’re dealing • Avalon 2008-12 torn down for repair. The only prob-
with U660E issues that, until now, were • Highlander 2008-12 lems found were sticking valves and a
a mystery. • Sienna 2010-13 fine metal in the pan.
The U660E appeared in the Lexus • Venza 2009-13 Not one component appeared to
ES350 and the Toyota Camry in 2007 About six months ago we started be damaged, but the valve body bores
and were followed by five additional seeing Toyotas with multiple com- and solenoids were clogged with a fine
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 The Mystery of the Rotating Bearing!

Turns out the

bearing is installed
in the case and
has a snap ring to
secure it.

aluminum. As the investigation went

from days, to weeks, to months, shops
were being inundated with this prob-
lem.
As with any investigation you need
the facts. Here are the facts of this situ-
ation:
• We have metal throughout the Figure 2
transmission; fine metal.
• We have sticking valves and worn
bores caused by this metal.
• We have torque converter slip and
ratio codes associated with it.

I made sure that the next time a

U660E failure occurred I would be
there. Then it happened: We got a trans-
mission in with the exact conditions
we were hearing about. It was time to
interrogate the subject!
During the unit teardown I found
a very interesting issue with the coun-
terdrive gear double ball bearing in the
case (figure 1). It moved! It rotated in
the case, freely, without resistance. But,
when I attempted to remove the bear-
ing, it felt like something was holding
it in place.
Turns out the bearing is installed in
the case and has a snap ring to secure
it (figure 2). It’s supposed to be a non-
removable bearing, but Toyota sells a
replacement.
So the bearing was spinning in
the case, which created the fine metal,
which, in turn, caused the shifting
issues and torque converter slip. But
we hadn’t discovered why the bearing
was spinning in the case. It was time to
dig a little deeper!
Then we noticed something even
more interesting: Nothing was dam-
aged except the case where the center
bearing rides. A closer examination
revealed the front of the case was close
to specification but the rear was way off
(Figure 3). Figure 3

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 The Mystery of the Rotating Bearing!

The ring gear and

carrier weigh 45
lbs. and the two
transfer gears are
fairly stout. That’s
all at the front of
the transmission.
It’s the back half
that’s having the
issue.
So what was happening was sim-
ply a torque issue. The unit is pretty
beefy for a front wheel drive: The ring
gear and carrier weigh 45 lbs. and
the two transfer gears are fairly stout
(Figure 4). That’s all at the front of the
transmission. It’s the back half that’s
having the issue.
From the center of the case the
planetary is connected to the transfer
gear by splines and a lock nut. The
planetary is then splined to the sun gear,
direct ring gear, and finally to the end
clutch (Figures 5 & 6). The sheer torque
of the unit, especially those mated to Figure 4

Case Support Point

Case Support Point

Figure 5

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 The Mystery of the Rotating Bearing!

Center

Figure 6

3.5L and 3.7L V6 engines, is what’s torch to cut it out, just to check the case,
causing the issue. It’s literally flexing measure it, and report the information
As it stands right the case where the bearing contacts it. to the industry.
As it stands right now there’s no When the bearing starts to rotate,
now there’s no aftermarket fix for this condition. It’s a it sends metal throughout the unit,
aftermarket fix costly repair, requiring you to replace
the case. And there’s nothing to stop it
solenoids, valve body bores, planets —
everywhere you look, it’s there. That’s
for this condition. from happening again. followed by a flare on the shift because
For now you can get a used case the solenoid is clogged with metal from
It’s a costly repair, for about $175. Make sure the bearing the planet.
is tight; if the bearing moves, that case Book ’em Dan-O! We found the
requiring you is bad, too. answer to our mystery… well the cause
If a good used case isn’t available, at least. I’m sure it won’t be long before
to replace the you’ll need a new case from the dealer, the aftermarket comes up with sleeves
case. And there’s part #35141-07011, at a cost of nearly
$1,200. You’ll also need a bearing for
or boring tools with a new sleeve and
bearing, but, until then, be aware of
nothing to stop it about $110, part #90369-72001, and a this issue. If you miss it, it’ll cost you
new snap ring for another $2.43; part a comeback.
from happening #90520-99110. Case closed!
The Toyota service manual says
again. you can press the bearing out and
replace it with a one. You can’t! We
tried to cut it out with die grinders but
that didn’t work. So we used a cutting
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