4R44E-5R55E ziP KiT
installation & Testing Booklet
01-26-12 4R44E-5R55E-ZIP-Booklet
©2012 Sonnax Industries, Inc.
Page 4
800-843-2600 • 802-463-9722 • F: 802-463-4059 • www.sonnax.com
TIME TESTED • INDUSTRY TRUSTED
Troubleshooting Tips (continued)
No Overdrive Servo Apply psi
• The coast clutch shift valve may be out of position, the bore worn severely or
the dumbbell-shaped valve (opposite bore from the TCC modulator) is not
being retained correctly.
• This “L” pin falls out of position easily.
• Timing valve may be stuck toward the end plug or the spring is not on
center, which causes it to coil bind.
• Kickdown valve may be stuck or spring missing.
No Od Servo Release
(No Overdriven 2nd in 5R & No 4th in 4R)
Mismatched separator plate at 5R/4R identification (
Figure 5
).
Od Band Failure, No Overdrive Release psi
The 3-4 shift valve may not be positioned due to a loose SSC solenoid. Bracket must
hold it in flush.
Broken Bands, No EPC Blow-Off, EPC psi Too High
Relief Tee near the pressure regulator is not opening or mismatched plate without a
hole here and no relief used at forward modulator end plug. The EPC spring bore
is often tapered, which alters spring operation. The Sonnax EPC and engagement
control kit
37947-11K
(not included in this Zip Kit) addresses this problem.
Low EPC, Soft Shifts, Slip in 3rd
Multiple EPC leakage points. Use the Sonnax EPC and engagement control kit
37947-11K
(not included in this Zip Kit), which address this entire circuit. Good
maximum EPC is 125-130 psi in OD and maximum of 144 in reverse. EPC should
not drop more that 15 psi during TCC apply.
Low EPC Pressure & No Lockup Control
If TCC modulator valve sticks, EPC will only obtain about 65 psi.
Flare on 2-3 Shift, 4R (3-4 on 5 Speed)
The servo pin bore is worn on the intermediate servo, or the spring on the piston is
too strong.
No 3rd or 4th
The 2-3 shift valve spring is missing or installed wrong. Also, the 1-2 shift valve
should stroke during wet air test (WAT) at the rectangular circuit five openings in
from EPC solenoid.
TCC Applied Prematurely, Harsh Shifts
If the solenoid is restricted or grounded, the TCC valve can stroke and apply the
converter clutch.
Poor Converter Charge, delayed Engagements
The balance spool or innermost bore for the pressure regulator is worn out.
Shift Solenoids
It is very rare to have a shift solenoid problem on these
units. It’s more common to have a loss of solenoid oil
psi due to loose end plugs.
EPC Circuit Testing
The most effective method to isolate the EPC circuit is
to perform an wet air test with fluid while the body is
still bolted to the case. This can be done in the vehicle
or at the bench. A quick test adapter can be made from
an old 4R/5R EPC solenoid. The coil housing and
valve will be removed and a plug or epoxy used to seal
the inboard circuit (
Figure 6
).
Supply 40-60 psi of air into the adapter. No leaks
should be visible at the locations shown in
Figure 7
.
Any leakage is reduction of EPC pressure and line rise
while in operation. Remember, though, as operating
temperature increases, valve clearance and the flow rate
(viscosity) of ATF increase. You can duplicate hot fluid
at the bench by filling the case and valve body with
solvent, then bolt up and test with the adapter.
Figure 6
Old 4R/5R
EPC Solenoid
Figure 7
“Tired” valve bodies leak at any
or all of these locations.
40-60 psi supplied to modified EPC solenoid/tool.
