Symptoms of bad OD Servo?

Tyler Sklenar

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What are the symptoms of a bad OD Servo or a broken E clip on it? I have no 4th gear and it’s not slipping or anything.
 

gamefanatic

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Bad OD would be shudder when attempting to transition to OD usually occuring at speeds above 40Mph. Usually at low throttle about 45mph or below 50% at speeds above 55mph.
It will feel like a misfire, but no misfires will be registered. You should get a code. P0741 or P0743 IIRC...

No 4th with no code could be a lot of things. Bad shift solenoid, broken wire, clogged valve train...

Here is a TSB if you haven't seen it already:

Article No.
98-10-7


05/26/98

^ TRANSAXLE - AX4N - NO 4TH GEAR AND DIAGNOSTIC TROUBLE CODES (DTCS) P0734
AND/OR P0761 FOR 1996-98 TAURUS/SABLE AND
1995-98 CONTINENTAL, AND DTC 648 FOR 1994-95
TAURUS/SABLE


^ TRANSAXLE - AX4N - RETAINING CLIP FORFORWARD CLUTCH CONTROL VALVE - SERVICE
TIP


FORD:
1994-98 TAURUS


LINCOLN-MERCURY:
1994-98 SABLE
1995-98 CONTINENTAL


ISSUE

No 4th gear operation (no 3-4 shift) and Diagnostic Trouble Codes (DTCs) P0734 and/or P0761 or 648 may occur on some vehicles. This may be caused by a broken retaining clip in the valve body that secures the forward clutch control valve and spring in place.

ACTION

Replace broken forward clutch control valve retaining clip with revised forward clutch control valve retaining clip. Refer to the following Service Procedure for details.

SERVICE PROCEDURE



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1. Inspect for a broken retaining clip by removing the valve body and then the valve body separator plate. Inspect the forward clutch control valve, spring, retaining clip, and valve body casting for damage (Figure 1).




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2. If the clip is broken and the forward clutch control valve and/or valve body casting is damaged, replace the main control. The retaining clip has just been revised to prevent the chance of breakage. The revised Retaining Clip (F8DZ-7F194-AA) has circular cutouts on the side of the clip in place of the square cutouts on the previous design level clip (Figure 2).


3. Inspect the new main control (if required) before installing it and replace this retaining clip for the forward clutch control valve and spring if it's not the new design (Figure 2) valve body

PART NUMBER PART NAME

F8DZ-7F194-AA Forward Clutch control valve
Retaining Clip


OTHER APPLICABLE ARTICLES: NONE

WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage

OPERATION DESCRIPTION TIME

981007A Inspect/Repair/Replace 2.4 Hrs
 

GEN 3 SHO FAN

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No 4th with no code could be a lot of things.

A weird thing I have seen long time ago on a Dodge Spirit with the 3.0L made by Mitsubitchi (great motor by the way) is the TPS (throttle position sensor) stop working and this resulted in no 4th shift...

The trans worked as nornal but no more 4th, to reach highway speeds, the engine climbed in high rpms to do the same work, which was a little bit scary.

Our 3.4L have some tables to run "without some timing infos" (cam and crank sensors)... Does he have also tables to run without infos from the TPS ? I personnaly never tryed this or rode something on this... Someone have to try it unpluged (someone with a working one).

(If it's the case of a faulty TPS, there is also a TSB on them...)
 

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