4R44E-5R55E ziP KiT
installation & Testing Booklet
©2012 Sonnax Industries, Inc.
4R44E-5R55E-ZIP-Booklet 01-26-12
800-843-2600 • 802-463-9722 • F: 802-463-4059 • www.sonnax.com
Page 3
TIME TESTED • INDUSTRY TRUSTED
Figure 3
If there is a hole
here, use includ-
ed EPC relief tee and
OE spring. If there is
no hole here, you
must use blow-off end
plug at forward
modulator valve
(Figure 4).
End plug
installs here.
Figure 4
This plate and part number
does not have an EPC relief
hole (Figure 3) and must be
used with OE part # 3L5Z-
7M203-JA end plug relief.
Figure 5
4R44E Plate
5R55E Plate:
has
bathtub checkball,
ahead of bolt hole.
Rebuilding Cautions
• Do not combine aftermarket parts or procedures
with this kit.
• Do not drill line-to-lube through the casting at the
pressure regulator valve.
• Do not use a stronger pressure regulator valve
spring or shim than the ones supplied.
• Do not remove springs or block reverse engagement
control valve.
Troubleshooting Tips
These tips are not about common problems such as blown gaskets or dirty valve
bodies. These only include valve body problems not visible during a rebuild.
No/Slow Reverse
• The SSA solenoid must be turned on, allowing flow through the solenoid, or
direct clutch will not apply until EPC rises to 20 psi. The direct clutch psi
will then slowly rise following EPC until clutch holds.
• Always install new servo pistons. Both servos are charged on the release side
in reverse.
• Inspect the center support sleeve, sealing rings and direct drum sleeve for cracks.
• Ensure the vehicle has line rise, as reverse will not engage until line is 120 psi.
delayed Reverse & Forward
The separator plate must be aligned with pins. If not, the bolt threads will separate
the case from the plate, causing a line pressure leak.
Servo Covers Blown Out of Case
Inspect for causes of high line psi such as pressure regulator bore or boost sleeve
wear, or line booster valve stuck inboard.
Servo Rubber Separated/Blown Off
This often occurs from pre-assembly damages, so inspect carefully before install-
ing. The rubber lip separation occurs from heat and high pressure. Both servos are
pushed toward the cover in reverse, so check for cause of high line pressure.
No 2nd, 1-2 Slide or Soft 2nd
Gear Starts
• Air test the rectangular circuit five openings in from
EPC solenoid. No cross leakage should be visible!
• Look for bore wear at the forward modulation
valve (repaired by
37947-11K,
not included in this
Zip Kit), This valve controls the servo apply rate.
• If the plug that lives in the middle of OE assembly
(repaired by
37947-11K,
not included in this Zip Kit),
is loose and bore leaks, a poor 1-2 and/or 2-3 results.
No 2nd or 4th, Erratic direct
Clutch, No Upshift
The solenoid regulator valve is likely out of position.
With SSB solenoid removed, the end of the casting to
edge of the long aluminum plug will measure 1.720"
when “L” pin is installed properly.
No Coast Clutch Pressure
• Inspect the bore plug for wear at the TCC regulator
valve. Sonnax TCC regulator sleeve kit
37947–09K
(not included in this Zip Kit) eliminates the leak
and bore plug here.
• The bore for the coast clutch shift valve wears out.
Insert the valve: no side-to-side movement should
be visible.
Separator Plate & Relief Valve information
