by Mike Brown

STREET SMART

2-3 Flare in the

5R55E
W
elcome to Street Smart — a
new column that’ll examine
real-world solutions to the
problems that face technicians every
day. Those of us who’ve been working
on automobiles for most of our lives
know that how we go about fixing a
problem might not always follow the
textbook solution. Because, when you
get right down to it, textbooks don’t fix
Fig 1 cars: Technicians do. And, in the real
world, we often find that following the
textbook only ends up leading us in cir-
Figure 1 cles. That’s when we need to start think-
ing… using our Street Smarts.
In this issue of Street Smart, we’re
going to look at 2-3 flare problems in
the 5R55E transmission. The 5R55E is
a 5-speed automatic transmission,
introduced by Ford in 1997. It’s used
with the 4.0L engine in Rangers,
Aerostars, Explorers and Mountaineers.
The 5R55E is mechanically the
same as the 4R44E and the 4R55E. The
difference is in how the computer com-
mands the upshifts (figures 1 and 2).
I’ve been on the ATRA HelpLine for
Fig 2 two years now, and in that time I’ve
Figure 2 heard problems with this unit nearly
every day. Is it in the transmission?
Computer? Wiring?… and so on. One
call we seem to hear over and over is the
5R55E with a 2-3 flare.
The call comes in like this:

“I have a 1999 Ford Explorer

that has a 2-3 flare. There’s a
code P0733 (No 3rd Gear) in
memory. I’ve adjusted the
EPC solenoid, went through
the unit and replaced both
servo pistons, but I still have a
flare on the 2-3 shift.”
Figure 3
Fig 3

50 GEARS May-June 2003

2-3 Flare in the 5R55E
Okay, let’s stop and look at what’s
going on in the transmission. The sole-
noid application chart (figures 1 and 2)
shows that in 1st gear, only shift sole-
noid 1 is energized, which applies the
forward clutch. To shift into 2nd, rather
than energizing solenoid 2, the comput-
er energizes solenoid 3, applying the
OD band. This actually overdrives 1st
gear.
Then, to shift into 3rd gear, the
computer turns shift solenoid 3 off and
solenoid 2 on. So to shift into 3rd gear,
the unit releases the OD band and Figure 4
applies the intermediate band (figures Fig 4
3 and 4).
With that in mind, what could hap-
pen that would create a flare on the 2-3
shift? Unlike the 4R44E and 4R55E,
the 5R55E applies the intermediate
band for 3rd gear; not the direct clutch.
At the same time, it releases the over-
drive band. So if the OD band releases
before the intermediate applies, you get
a 2-3 flare. The flare is a timing issue;
the intermediate band is applying too
slowly. Figure 5 Fig 5
So let’s recap on what we’ve done
so far:

1. We went through the unit. The for-

ward clutch, direct clutch and
coast clutch all air check okay.

2. We’ve installed new servos, and

new intermediate and overdrive
bands. The bands are adjusted
properly and air check fine.

3. Line pressure tests are within

specs (figures 5 and 6). We even
bumped the pressure up a little by
adjusting the EPC solenoid.

4. All shift solenoids are well

between 22–48 ohms of resistance
(figure 7). Figure 6

Let’s do more than just look at the

valve body; let’s disassemble it com- that even if a solenoid has good resist- We’ve had a lot of calls on 5R55E
pletely. Take the time to flat sand the ance, it can still fail a functional test or with a 2–3 flare and code P0733 (No
valve body, making sure it’s nice and leak test. If you don’t have the tools for 3rd Gear). Code P0733 takes you to
flat. This will help prevent crossleaks. testing solenoids, you’re throwing pinpoint test A: Shift solenoid electrical
Don’t just check the valves for wear, money down the drain. With today’s circuit test. Remember, this unit has 3rd
inspect the bores too, and make sure transmissions, not having a dynamic gear; the problem it has is a 2–3 flare.
the end plugs fit snug into the valve solenoid tester is like removing and Most of the time it turns out that
body. installing a transmission using only shift solenoid 2 is leaking out the end,
An important point to remember is hand tools, or without a lift. which delays the stroke of the 2–3 shift

52 GEARS May-June 2003

valve (figures 8 and 9). When the
computer doesn’t see the RPM drop Solenoid I.D and 3. S S 4 22-48 ohms
right after it energizes the solenoid, it
assumes the unit didn’t shift into 3rd
Resistance 4. T C C 9-16 ohms
gear, so it sets code P0733. 1. E P C 3.1-5.7 ohms
5. S S 3 22-48 ohms
Replacing all the solenoids during
2. S S 2 22-48 ohms
a rebuild is one way to prevent this type 6. S S 1 22-48 ohms
of problem. But it’s not really practical,
due to the high price and lack of avail-
ability of most solenoids. And remem-
ber, just because a solenoid is new
doesn’t guarantee it’ll function proper-
ly. The only way to be completely sure
that all of the solenoids are working
properly is to test them… electrically
and mechanically.
Testing solenoids is a sure way to
save time and money. It’ll help you
track down many problems that don’t
show up using a typical electrical diag-
nosis. And that’ll help keep you from
pulling units a second time. That’s not
just smart… that’s Street Smart!

(See figures 8 and 9 on page 54.)

Figure 7

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GEARS May-June 2003 53
2-3 Flare in the 5R55E

Figure 9
Figure 8

54 GEARS May-June 2003