Here in the northern Midwest, we are experi-encing the determined hammering of pileatedwoodpeckers. If you are not familiar with

what a pileated woodpecker looks like, you may re-call the “Woody the Woodpecker” cartoon on TV backin the day. For animation, add the audio effects of anair chisel on a metal bench!

Once male and female birds have paired, they willfiercely protect their territory from competitors, evenif it is only their own reflection in windows or vehiclemirrors. And they won’t leave until they peck hardenough to break the pane! Once the competitive threathas disappeared, they move on to discover anotherbird in another window or mirror. For property own-ers, one solution is to cover the window with paper sothe birds can’t see their reflection.

You may be asking, ‘What does a woodpecker havein common with an AW 6 transmission?’ Every win-dow is an opportunity for a woodpecker, every AW 6an opportunity for service. You need paper to resolvethe pileated problem, and you will need paper to di-agnose the AW 6. Forgoing the paper when handlingeither problem can result in wasted time and money.

Chances are you may already have some experi-ence with the AW 55-50. A good way to begin under-standing the AW 6 is to compare the main operatingdifference between it and the AW 55-50.

The AW 55-50 uses three linear solenoids to control

AW Six-Speed Valve-Body Diagnosis

By Bob Warnke©Sonnax 2010

clutch pressure (SLS), line rise (SLT) and TCC (SLU).The SLT and SLS solenoids are multipurpose and de-pend upon the valve position of five on-off shift sole-noids.

In the AW 6 each clutch has a designated linear so-lenoid, reacting on a clutch-control valve. The controlvalves regulate each clutch circuit independently. Thetwo on-off solenoids are cycled at the beginning ofeach upshift or downshift from third to sixth to inter-rupt oil flow to the clutch. Controller-area-network(CAN) control, adaptive learning, hill hold,forward/reverse engagement and converter-clutchoperation are all more refined in the AW 6 than theywere in the 55-50.

Aisin has designed the hydraulics so that one TCMprogram can be used in multiple vehicles. This re-duces development time for AW. It also benefits us.Although transmission and valve-body parts do notinterchange, the diagnostic routine explained herewill apply to all the AW6 FWD units.

Transmission identificationTF-60SN/09G in VW: Oil pan is on the bottom.TF-81SC in Ford/Mazda: Wide oil pan facing radi-

ator; longer case.TF-80SC/AF-40 in Volvo/PSA/Saab: Narrow,

deeper oil pan facing radiator; shorter case. Use the power-flow chart (Figure 1) and the valve-

Solenoid-Power Flow AW6 FWDRange Solenoid Clutch Brake O.W.C.

Ford/Volvo/PSA SSC SLC1

SSD SLC2

SSE SLC3

SSF SLB1

SSA S1

SSB S2

C-1 C-2 C-3 B-1 Band

B-2 Clutch

F-1

VW N92#5 N282#9 N90#3 N283#10 N88 N89 K-1 K-2 K-3 B-1 Clutch

B-2 Clutch

F-1

P X X X XR X X X X XN X X X X

Neutral control X X X X X

D

S

1st X X X Z Z X Z X2nd X X X X3rd X X Cy Cy X X4th X X Cy Cy X X5th X X Cy Cy X X6th X X Cy Cy X X

SSC & SSE solenoids have residual clutch pressurefeeding back to the opposing clutch-control valve

X=On =Off Z=On during engine braking Cy=Cycled during upshift/downshift

Solenoid for Clutch C-1 C-2 C-3 B-1 TCC applies after 2-3 shift, modulated slip during upshift/down shift.Resistance – Ohms 4.0-8.0 4.0-8.0 4.0-8.0 4.0-8.0 10-16 10-16 Linear solenoids operate at 300Hz

Solenoid Flow N.O. N.O. N.O. N.O. N.C. N.C. N91/TCC/SLU is N.C.; N93/EPC/SLT is N.O.

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body illustrations (figures 2 and 3) tobegin diagnostics.

One of the focal points for diag-nostics should be monitoring C-2/N282 and C-3/N90 solenoidactivity. Common complaints withthis valve body include 2-3 flare, lossof or slip on 3-4, and harsh coast 5-3or 4-3 downshifts. Each linear sole-noid reacts on a clutch-control valve,which then affects clutch applicationand release. Having one solenoid foreach clutch allows for “skip-shift”upshifts and downshifts. Without ascan tool or pressure gauge, identify-ing which solenoid, clutch or clutch-control valve is being activatedbecomes very difficult.

As the torque-converter clutchgenerally applies after the 2-3 shifts,TCC application can easily be con-fused with a 3-4 shift. The TCM mod-ulates TCC slip or releases theconverter briefly during upshifts anddownshifts. The TCM can use lockupto control engine braking in certainapplications.

Test drive To begin, you will need the power-

flow chart to help identify which so-lenoid or clutch valve requires

2

3

ExampleC-3 adjuster: Turn screwoutward to increase C-3clutch pressure. 1/4 turnis about 4 psi clutch difference. Would suggest1/2 turn first attempt.

Ford/Mazda

TCC solenoid Reverse2-3, 4-53-2, 5-4

3-44-3, 6-5, 6-3

1-2, 3-25-6, 6-5

Line rise & shift quality

SSF

SSE

SSC

SSD

Alignment holes (3)

Hill hold, N-D, 4-5, 5-4

3-4, 4-3

TF-60SN

1 – primary pressure regulator

2 – secondary pressure regulator

Control-valve index:Min. 0.187 in. (4.74mm), max. 0.220 in. (5.58mm) from end of casting

N 91TCC

G 194

N 89

Alignmentpin

Alignment pin

N 93EPC

G 193

N88

7N 90 K3

6N 283 B1

5N 282 K2

4N 92 K1

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Use 2 alignment pins of 0.238-inch diametercontinues next page

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Comparing two rpm inputs willidentify each shift, as well as TCCfull application/zero slip or partialmodulation. The test drive shouldidentify the complaint as being re-lated to a specific clutch or to allshifts. If only one clutch is in-volved, focus on the linear sole-noid and clutch-control valve thatexhaust and charge that clutch.The AW6 input-speed graph(Figure 4) shows engine speed inred and turbine speed in green.Two shifts have been captured inthis graph, showing a compatibleramping of the two signalsthroughout.

Pressure testing Figure 5 shows typical C-1

clutch pressure. With harsh up-shifts and downshifts, it is com-mon to have elevated linepressure, which can be caused by aworn main pressure-regulator boreor PCA solenoid. To isolate this,tap into C/K-1 pressure, clear thecodes and monitor N93/PCA am-perage. With elevated line pres-sure, engagements become harshand downshifts bumpy, and the 2-3 develops a flare under light ac-

attention. A scan tool with graph-ing capability is the second of threerequirements for that drive. Thethird requirement is unusual: Ifpossible, have the vehicle ownerdrive and duplicate the concern, orat least provide a detailed descrip-tion of how to duplicate the prob-lem. Because this is a six-speedwith skip-shift capability and amodulated converter clutch, dupli-cating and isolating the driver’scomplaint can be very difficult.Operator driving habits, TCMadaptability and terrain will all

greatly affect the shift strategy. I would suggest graphing in real

time, monitoring engine speed andturbine speed. When shift qualityis smooth and correct, turbinespeed will parallel engine speed.With a flare/neutral condition, theengine speed spikes up. With abind or bumpy shift caused by anoverlap issue, the turbine speedwill dip at the beginning of theshift. Generally one shift will havethe problem, so you could comparea good rpm ramp with a poor rpmramp.

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Engine speed (red)

Turbine speed (green)

AW 6 Input Speeds

5 Typical C-1 Clutch Pressure (Typical of All FWD AW6)

BAR PSI

13.8 20013.1 19012.4 18011.7 17011 16010.3 1509.6 1408.9 1308.2 1207.6 1106.8 1006.2 905.5 804.8 704.1 603.4 502.7 402 301.4 200.68 10

0

58-61 D/idle

19-20 C-1

Park to Drive

Drive acceleration to 1-2 shift

2-3 shift & 3-4 4-5 5-4, 6-4 4-3-2

225 StallDrive

190, 180just priorto down-shifts

P, N

Point of engagement,1.2 seconds

Amount of line rise is torque proportionate.

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celeration. Elevated line pressuremay not set or be caused by codes.

With the complaint of harshshifts from 3 to 6 and 6 to 3, andC/K-1 pressure has not been ele-vated, you should tap TCC release(Figure 6). As mentioned, the TCMstrategy brings the converterclutch on directly after the 2-3shift. It will go to full applicationat light load. If you are graphingengine and turbine speed, linesshould be overlaid at full applica-tion. TCC will be modulated off todisconnect the turbine shaft duringsubsequent upshifts and down-shifts. If this control is not evidenton your graph and release-pres-

sure test, inspect the TCC controlbore for wear. The scan tool willindicate an amperage change, butthe TCC release pressure will notbe affected (Figure 7).

If the vehicle is driven in thiscondition for too long, the convert-er lining can be damaged.

Clutch-circuit testingTransmission circuits can be

tested in the vehicle as explainedearlier or with the valve body re-moved. For a wet air test (WAT),prime the circuit with ATF, thenfollow by applying 40-60 psi of air.The familiar “dull thud” of a pis-ton stroke confirms a good circuit.During the WAT, if the pressure

drops and theclutch does notapply, or vents,you have identi-fied a leak. Onthe 09G, for ex-ample, if the K-2piston does notstroke or fluidexhausts fromanother port, theK-2 case sleevemay have rotat-ed.

Valve-bodyinspection

If you deter-mine that thevalve body is at

fault, or you are inspecting a valve-body core for future use, inspectthe bores mentioned previously.Exploded view, vacuum-testing lo-cations for each bore, and reliefand spring identification are avail-able at the Sonnax Web site,www.sonnax.com.

As mentioned, the TCC controltends to wear first, then solenoidmodulators, followed by K-2/K-3clutch control and then main orsecondary regulator valves. If yourtest drive indicated a harsh shift inone gear and line pressure is good,focus on the specific clutch-controlvalve identified in the power-flowchart. Bore wear in this type ofvalve body is similar in appear-ance to that found in AW 55-50 orother units. Wear appears as a pol-ished half-moon area, typically onthe loaded side of the bore and atthe ends of the valve travel. Thevalves themselves rarely have wit-ness marks or evidence of a prob-lem.

Diagnosis and the pileated prob-lem

At this point you should realizethat this transmission offers a largewindow of opportunity. The fact isthat paper can help you isolate aproblem in the AW 6; being hastyin your evaluation could costmoney by unnecessary transmis-sion removal and misdiagnosis.

For those of us with a pileatedwoodpecker breaking windows,we should remember the follow-ing:

Cover the windows with paperfor at least two weeks, allowingtime for the birds to find anotherterritory. Taking the paper downtoo early will result in the wood-pecker coming back to finish thejob. This results in time and moneyto repair damage.

To examine the valve bodies,their vacuum-test locations andother problems refer to www.son-nax.com.

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K1 K2 Lube B2 TCC release

Solenoid modulator

TCC controlLine pressurelarge &smalldiameter

29

0.392 in. TEE green0.334 in. O.D.0.030 in. wire0.793 in. free length

Rubber

0.392-in. cup white0.245 in. O.D.0.024 in. wire0.598 in. free length

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