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1/626 GEARS May/June 2006

The Honda Civic has become a

popular vehicle for modifica-

tion by import performance

enthusiasts. While the manual transaxle

is usually the choice of the hardcore

performance enthusiast, there are quite

a few automatic-equipped Civic own-

ers looking for performance shifts.

If you do any high performance work

at your shop, youre likely to have an

automatic-equipped Civic owner come

in asking you about making the shifts

firmer. In this issue, were going to go

over a few simple modifications for

firmer shifts and TCC apply on the

A4RA / B4RA transaxle used in the

19962000 Civic.

This article takes a conservative

approach to making the shifts firmer.

You want to be wary of making one

of these units shift brutally hard, as its

main weakness is the clutch drums.

If you have the unit apart, check all

the drums, specifically the first gear

clutch drum. Its common for this drum

to crack right around the center, just

outside the recess where the shaft nut is

located (figure 1).

Before we dive in

If youve worked on many Honda

transaxles, you already know that you

have to remove and disassemble the

transaxle to reach the valve body. Both

you and your customer need to be

keenly aware of this fact. Shift feel

and firmness can be a subjective issue,

and the only way

to be certain your

customer is going

to be happy with

the results is afterthe modifica-

tions have been

performed. The

customer needs to

understand that,

if the unit has to

come back out

to fine tune shift

feel, the labor

isnt free.

With that

said, a simplefirst approach is

to adjust shift feel without going inside

the unit. This can be done by adjusting

the linear solenoid, shown in figure 2.

This adjustment is sensitive; its best

to start with 1/8 to 1/4 turn clockwise,

then road test to assess the results. Keep

in mind that youll have to remove the

solenoid to adjust it.

Adjusting the linear solenoid is a

simple modification and is easily revers-

ible, but it has one major drawback:firmer shifts can be achieved up to a

point, but too much adjustment can have

negative effects on TCC control. Thats

because the linear solenoid isnt only

used to control shift feel; its also used

to control the torque converter clutch

full apply timing. Cranking up the lin-

ear solenoid can lead to an abrupt TCC

apply and lugging the engine, especially

under light throttle acceleration.

When you increase the linear

solenoid pressure, instead of havingpartial TCC apply at light throttle, it

Hot Rod

Civic19962000 Honda CivicShift Feel Modifications

Figure 1

by Mike Van Dyke

Remove linear solenoid to adjust end plug

Figure 2

AdjustmentPlug

Linear Solenoid

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can go straight to full apply as soon as

TCC is enabled. When this happens the

engine will lug down, the dashboard

will rattle, and acceleration will be

poor until vehicle speed increases, or

until you press down far enough on the

throttle for the PCM to command the

TCC to release.

After adjusting the linear solenoid,

be sure to drive the vehicle at lightto medium throttle to see if there are

any negative effects on torque converter

clutch operation.

Lets Dive In!

To get even firmer shifts without

TCC side effects, or to modify TCC apply,

we have to go inside the unit. There are

a couple of ways to approach modifying

shift feel: accumulator springs, increase

line pressure, etc. The easiest and most

effective modification Ive found is to

simply adjust the CPC (Clutch Pressure

Control) valve in the secondary valvebody. (figure 3). The CPC valve is con-

trolled by linear solenoid pressure, but

the benefit here is adjusting the CPC

valve wont affect TCC control.

Its very common for the CPC valve

spring to break, so youll want to remove

it for inspection. Youll need a 5 mm

hex key wrench and a 10 mm box end

wrench to adjust or remove the CPC

valve (figure 4):

Hold the 5 mm hex key wrench and

loosen and remove the 10 mm lock

bolt. Measure and record the depth of the

adjustment plug so it can be reas-

sembled to the same position.

Hot Rod Civic

Figure 3

Secondary Valve Body

CPC ValveSpring

CPC Valve Lineup

Always Remove CPC valve for cleaning and to check for broken spring

Measure and record adjustmentplug depth before disassembly

Figure 4

5mm Hex KeyWrench

10mm Box EndWrench

Hold the adjustment plug with 5mm hex key andloosen lock bolt with 10mm box end wrench

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4/6GEARS May/June 2006 29

The CPC valve spring isnt available separately from

Honda; you must purchase the complete secondary valve

body. A replacement spring is available from Sonnax, part

number 88894X. The Sonnax spring is a little different from

the OEM, so be sure to follow their installation and adjustment

procedures.

Turning in the CPC valve adjustment an additional 1/8 to

1/4 turn clockwise will provide moderately firmer shifts. 1/2

turn to 1 turn clockwise will create very firm shifts. Blocking

the valve inboard will get you into the 12 chirp zone. Keep

Figure 5

Lock-Up Valve Body Spacer Plate

TCC Release Orifice

Enlarge to0.100

TCC modification: Drill TCC release orifice to 0.100

Turning in

the CPC valve

adjustment

an additional1/8 to

1/4 turn

clockwise

will provide

moderately

firmer shifts.

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The new SchafferProgrammable Controller willnot replace the Schaffer Shifter,it will be programmed for units

that the Schaffer Shifter cannotcontrol.

Features include:12 individually controllednegative outputs12 individually controlledpositive outputsEight switch indicator lights

Keep your eyes open for thenew programmable controller tobe released in April 2006!

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7/28/2019 2006_05_26 honda

5/630 GEARS May/June 2006

Hot Rod Civic

in mind that turning up the CPC adjustment will also make the

engagements firmer.

TCC Modifications

1. Enlarge the TCC release exhaust orifice to 0.100

(figure 5).

2. Increase the spring pressure about 40% on the Lock-Up Control Valve (figure 6) by shimming the spring

about 0.200. This can be accomplished by dropping

a G4AEL valve body orifice cup or some washers

inside the valve in the spring pocket. To check the

spring pressure on a scale, push the valve down over

the spring until just before the end of the valve touch-

es the scale: It should have about 2 pounds of spring

pressure.

3. Increase the spring pressure on the Torque Converter

Check Valve (figure 6) by 30% by dropping some

washers inside of the torque converter check valve toshim up the spring about 0.150.

That just about wraps up our fun for this issue. Remember,

dont get too crazy with this unit at least, not until someone

starts making billet clutch drums!

Figure 6

Lock Up Control Valve

Install 0.200 Shim

Regulator Valve Body

Install 0.150 Shim

Valve in first,Spring on top

Torque ConverterCheck Valve

TCC modification: Shim the lock up control valve spring 0.200 and shim the torque converter check valve spring 0.150

Remember, dont get too crazy with this unit

at least, not until someone starts making billet clutch drums!.

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