26 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, you’re likely to have an automatic-equipped Civic owner come in asking you about making the shifts firmer. In this issue, we’re going to go over a few simple modifications for firmer shifts and TCC apply on the A4RA / B4RA transaxle used in the 1996–2000 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. It’s 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 you’ve 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 after the modif ica-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 isn’t free.

With that said, a simple first 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; it’s best to start with 1/8 to 1/4 turn clockwise, then road test to assess the results. Keep in mind that you’ll 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. That’s because the linear solenoid isn’t only used to control shift feel; it’s 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 having partial TCC apply at light throttle, it

Hot Rod Civic1996–2000 Honda CivicShift Feel Modifications

Figure 1

by Mike Van Dyke

Remove linear solenoid to adjust end plug

Figure 2

Adjustment Plug

Linear Solenoid

26Civic-MikeVD.indd 2626Civic-MikeVD.indd 26 4/17/06 10:22:31 AM4/17/06 10:22:31 AM

Superiorplcd.indd 27Superiorplcd.indd 27 4/11/06 3:28:11 PM4/11/06 3:28:11 PM

28 GEARS May/June 2006

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 light to medium throttle to see if there are any negative effects on torque converter clutch operation.

Let’s 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 I’ve found is to simply adjust the CPC (Clutch Pressure Control) valve in the secondary valve body. (figure 3). The CPC valve is con-trolled by linear solenoid pressure, but the benefit here is adjusting the CPC

valve won’t affect TCC control. It’s very common for the CPC valve

spring to break, so you’ll want to remove it for inspection. You’ll 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 Valve Spring

CPC Valve Lineup

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

Measure and record adjustment plug depth before disassembly

Figure 4

5mm Hex Key Wrench

10mm Box End Wrench

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

26Civic-MikeVD.indd Sec1:2826Civic-MikeVD.indd Sec1:28 4/17/06 10:23:04 AM4/17/06 10:23:04 AM

GEARS May/June 2006 29

The CPC valve spring isn’t 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 1–2 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 additional 1/8 to

1/4 turn clockwise

will provide moderately

firmer shifts.

The industry's first, ever,completelyreprogrammablehandheld ransmission controllerfor the later multi-stagesolenoid sequencing units isalmost here.

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

No other Parts Washer on the market has the Quality, Features, Horsepower, and Warranty offered at these prices !

800-331-6405 www.instaclean.com

Insta-Clean quality that can’t be beat ! Now at a price that can’t be beat !

IC-4, 2-H.P. IC-7, 3-H.P. IC-10, 5-H.P.*$2,695.00 $3,895.00 $4,995.00

* IC-10, 3-Phase Electric Heat Prices are for continental US F.O.B. AZ. Prices are subject to change without notice.

26Civic-MikeVD.indd Sec1:2926Civic-MikeVD.indd Sec1:29 4/17/06 10:23:42 AM4/17/06 10:23:42 AM

30 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 to shim up the spring about 0.150”.

That just about wraps up our fun for this issue. Remember, don’t 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 Converter Check Valve

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

Remember, don’t get too crazy with this unit… at least, not until someone starts making billet clutch drums!.

26Civic-MikeVD.indd Sec1:3026Civic-MikeVD.indd Sec1:30 4/17/06 10:24:03 AM4/17/06 10:24:03 AM

parker5-06.indd 31parker5-06.indd 31 4/17/06 2:00:03 PM4/17/06 2:00:03 PM