B&M 70226 TRANSKIT FOR GM 4L80E TRANSMISSION - Manual (Page 5)

5
which connectors go to which solenoid
(See Fig. 1). Pay particular attention
to the location of the cable clamps and
dipstick stop bracket. Notice how the
connectors and wires are colored.
Remove connectors from pressure
switch assembly and solenoids then
tie the wires up out of the way.
STEP 4. Remove all except the cen-
ter valve body bolt. Pull the lube pipe
out of the case, pulling it out first at
the front then at the rear. When re-
moving the pressure switch, be sure
to recover all 5 switch assembly O-
ring seals as it is removed. Hold the
valve body firmly with one hand and
remove the remaining bolt slowly. No-
tice how the Manual Valve is engaged
to the detent lever as you remove the
valve body from case. Caution: There
are eight (8) check balls in the case
above the valve body along with sev-
eral pints of oil (export units and some
early models have nine (9) check
balls). Have your drain pan ready to
catch the oil and check balls. Save all
the check balls in a secure place where
they won’t get lost.
STEP 5. Remove the 6 screws hold-
ing the accumulator housing to the
valve body (See Fig. 7). Be careful to
keep the 2 or 3 accumulator springs
located inside the housing aligned with
their respective bores.
STEP 6. Remove all of the old gasket
material stuck to the Case flange, Oil
Pan, Vavle Body, Spacer Plate and Ac-
cumulator Housing.
MODIFICATIONS
Pressure Regulator
STEP 7. Heavy Duty and High Per-
formance Street levels:
Remove the snap ring at the end of
the pressure regulator bore (See Fig.
2). Use a screwdriver to push against
the spring loaded Boost Valve sleeve
while removing the retaining ring. Re-
move Boost Valve Sleeve and Valve,
Pressure Regulator Spring and the
Pressure Regulator Valve. Reassemble
the pressure regulator assembly in re-
verse order using the supplied RED
Pressure Regulator Spring, Boost
Valve, Boost Sleeve and Retaining
Ring. Important: Early model 4L80E
(1991-early 1992) require the Boost
Valve and OEM pressure regulator
valve to be modified. Follow Sonnax
Instructions that are provided to make
the required modifications.Do not in-
termix early and late Pressure Regu-
lator Valves, Booster Valve or Sleeve.
The provided Balance Oil Plug should
only be installed when the transmis-
sion is out of the vehicle because the
pump assembly needs to be out of the
unit. It is installed on the backside of
the Pressure Regulator Valve, refer to
the Sonnax instructions provided. Make
sure the retaining ring is fully seated
in its groove when assembled. If the
retaining ring is not fully seated in its
groove, the pressure regulator assem-
bly will blow out of its bore when the
engine is started, resulting in NO LINE
pressure.
Spacer Plate
STEP 8. Heavy Duty and High Per-
formance Street levels:
Drill the orifices as indicated (See Fig-
ure 3) with the supplied drill bits. Be
careful to use the specified size drill
and only drill the holes indicated for
the Perfomance Level you have cho-
sen. For best results first use an in-
delible pen to mark the holes to be
drilled on the spacer plate, and then
double check your marks against Fig-
ure 3. Drill the smaller hole sizes first.
If you incorrectly drill your spacer
plate, you can obtain one from your
GM Parts Department, B&M does not
stock 4L80E Spacer Plates. Be sure
to take the build Year and Model infor-
mation (See Fig.1) located on the tag
on the right hand side of the transmis-
sion when ordering parts for your
4L80E.
Reassembly
STEP 9. Replace the Pressure Con-
trol Solenoid (PCS) Filter and Shift So-
lenoid Feed (SSF) Filter (See Fig. 4).
in the Valve Body with the new filters
supplied in the kit. Coat the O-rings
on the filters with clean ATF prior to
installation. The PCS Filter is removed
by pulling it straight up out of the Valve
body. Remove the SSF filter by first
removing the Filter Bore Plug Retain-
ing Pin and then the Manual Valve from
its bore. Very carefully insert an 8”
long 3/8” drive extension into the
Manual Valve bore and gently push the
SSF filter out of its bore. Reassemble
both filters in reverse order of disas-
sembly. Remove the TCC Solenoid
Screen from the case (See Fig. 8) and
replace it with the new filter from kit.
STEP 10. Apply a few dabs of Petro-
leum Jelly to both sides of the CLEAN
drilled and deburred Spacer Plate then
stick the Spacer Plate Gaskets (See
Fig. 5) onto the appropriate sides of
the plate and line up the holes. Place
the Spacer Plate on the Valve Body
and insert several Valve Body Screws
to help line up with the holes.
Accumulators
STEP 11. Heavy Duty Level Only:
Remove the 4th Accumulator piston
from its bore (See Fig. 6). Install the
3/8” long WHITE or RED spacer over
the piston pin and reinstall the piston.
STEP 12. High performance Street
Level Only: Remove the 4th Accumu-
lator piston from its bore (See Fig. 6).
Install the 1/2” long ORANGE or
GREEN spacer over the piston pin and
Figure 2: Pressure Regulator
Pressure
Regulator
Bore
RED
P/R
SPRING
New
Retaining
Ring
Reassemble the Pressure
Regulator in this order