91 bronco with AOD

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Thumper22866

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I have a 1991 bronco 5.0 with AOD tranny, while driving the tranny will drop gears suddenly while sometimes slipping into neutral, I can run through the gears shifting manually on the tree, but once back into OD or D it will drop gears or shift to neutral again. I have just recently rebuilt the complete drive train, and there are less than 500 miles on it since rebuild. I have done many modifications to this can list if needed.

 

NaturalRampage

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I had a similar issue on my tranny too. When I step on the gas it was in "neutral" but then a few seconds later it shifts. My problem was very low tranny fluid. See if thats at a good amount. And yeah everything you done to your tranny would help us diagnose the problem on this one. Good luck!

 

miesk5

96 Bronco 5.0
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yo,

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

http://broncozone.com/topic/14269-code-reader/page__pid__74587__mode__threaded

We can ruel out a few thAngs this way (DTC 67 Neutral Drive Switch (NDS) Circuit Open, etc.)

The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.

Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion first.

Look Codes up in my broncolinks.com site using the new Search function.

And Post em here according to:

KOEO

&

KOER

=============

aodtroubleshooting.JPG

=======

Trouble Shooting, COMPREHENSIVE; "...from the AOD service manual..." Source: by duanemyhre

No 3-4 Upshift or Slipping 4TH Gear TSB 93-23-18 for 80-93 Bronco, Econoline & F 150

This TSB article is being republished because of the occasional need for the information it contains. Originally published as TSB 83-13-10 in June of 1983, this article is not easily locatable in many dealerships today; the model application has been updated. Also, The Service Manual contains this information.

ISSUE:

A no 3-4 upshift condition or a slipping 4th gear may result from

•Direct clutch checkball leaking

•Missing plug in end of output shaft

•Case bore wear

•Leakage at O/D band servo piston and/or case bore

•Seal leakage at 3-4 accumulator piston

•Blocked hydraulic circuit condition

•Improper valve body attaching bolt torque

•Leaking governor circuit

•Torque converter damper/hub malfunction

ACTION:

Road test, diagnose and repair the transmission as required. Refer to the following diagnostic and repair procedure for service details.

PRELIMINARY CHECKS/INFORMATION

1.Road test the vehicle to verify the customer complaint. A no 3-4 upshift is characterized by staying in 3rd gear. A slipping 4th gear is characterized by engine cut-loose on 3-4 upshifts and limited or no 4th gear drive capability.

2.Check TV rod/cable to see if bent, kinked or sticking. Repair or replace rod/cable as required.

3.Check TV linkage (could be misadjusted long). On older models, bent, sticking or misadjusted TV Linkage will not properly synchronize with the carburetor/throttle body lever at the time a 3-4 upshift should occur.

4.Check control pressure and throttle pressure to identify that they are within specifications. Use the following guide pressure specifications:

GUIDE PRESSURE SPECIFICATIONS *

GEAR RANGE IDLE--------------- W.O.T.

P,N,O/D,D,L 55-65 PSI---------- 175-205 PSI

Reverse 75-95 PSI--------------- 250-300 PSI

Pressures are typical with TV pressure adjusted to specification per Service Manual (approx 32 psi using gauge block). Refer to applicable model-year AUTOMATIC TRANSMISSION SPECIAL SPECIFICATIONS ISSUE for exact specifications, if required.

DIRECT CLUTCH PRESSURE TEST

Leakage in the direct clutch circuit is usually caused by a leaking checkball in the direct clutch piston. Replacement of the direct clutch piston will alleviate this condition. However, since other factors can be involved, the following additional checks/verifications will aid in making a comprehensive diagnosis of no 3-4 upshift and/or no 4th gear symptoms.

The direct clutch pressure test outlined below will diagnose a low pressure condition or leakage in the direct clutch circuit. A difference of 15 psi or more between direct clutch pressure and line pressure (read at the forward clutch pressure tap) will prevent a 3-4 upshift.

1.Attach 0-300 psi (0-2068 kPa) pressure gauges to the forward clutch and to the direct clutch pressure tap, Figure 1.

aod0-300 psi (0-2068 kPa) pressure gauges.gif

Figure 1 - Article 93-23-18

a.Gauge accuracy must be capable of distinguishing a 15 psi (110 kPa) difference. (If this test is done in conjunction with a control pressure test, pressure gauges will be attached to all pressure taps).

b.Connect sufficient flexible hose to be able to read the gauges inside the vehicle.

CAUTION: PRESSURE GAUGES AFFECT THE SHIFT QUALITY OF THE TRANSMISSION. DO NOT ACCELERATE OR DECELERATE RAPIDLY WHILE PRESSURE GAUGES ARE ATTACHED. TRANSMISSION FAILURE MAY RESULT.

2.Drive the vehicle. When pressure is applied to the direct clutch, note the difference between line pressure (read at the forward clutch pressure tap) and direct clutch pressure (read at the direct clutch pressure tap).

3.If the difference in pressure is less than 15 psi (110 kPa), the direct clutch circuit is OK.

4.If the difference is greater than 15 psi (110 kPa), there could be a leak in the direct clutch pressure circuit.

a.The gauges on the forward and direct clutch pressure taps can be switched to confirm that gauge calibration difference is not the cause.

b.If a 15+ psi (110 kPa) pressure differential can be confirmed, proceed to the "DIAGNOSTIC PROCEDURE NO. 1" (leakage indicated), or to "DIAGNOSTIC PROCEDURE NO. 2" (slips in 4th), if applicable.

c.If a 15+ psi (110 kPa) pressure differential cannot be confirmed, proceed to "DIAGNOSTIC PROCEDURE NO. 3" (no leakage indicated).

DIAGNOSTIC PROCEDURE NO. 1 - NO 3-4 UPSHIFT WITH DIRECT CLUTCH PRESSURE DIFFERENCE GREATER THAN 15 PSI (110 kPa) - (indicates leakage in direct clutch circuit)

NOTE: BURNT DIRECT CLUTCH PLATES WILL HELP TO CONFIRM LEAKAGE IN THE DIRECT CLUTCH CIRCUIT. REPLACING ONLY THE PLATES AND NOT FINDING THE CAUSE COULD RESULT IN A REPEAT REPAIR.

1.Check valve body bolt torque. Correct torque is 9-11 N-m (80-97 lb-in).

2.Remove the valve body and check to see if main control gasket is blocking an orifice.

3.Check valve body-to-case mating surfaces for nicks or porosity.

4.Check the direct clutch piston check ball for leakage (inspect check ball for freedom of movement). Improper seating of check ball will cause leakage:

a.Turn piston upside down (flat side of piston facing you) allowing the check ball to seat in the piston.

b.Pour a small quantity of solvent over the check ball. If solvent drops past the check ball, replace the piston.

5.Inspect the output shaft feed passages and the cup plug for leakage.

a.Apply 5-10 psi (34-69 kPa) air to the output shaft feed passages, Figure 2.

aodclutch output shaft seals.gif

Figure 2 - Article 93-23-18

b.If air comes out of the wrong feed passage, replace the output shaft.

6.Check the direct clutch piston seal rings (inner and outer) for leakage.

7.Check all direct clutch output shaft seals for freedom of movement and for metal shavings and burrs between the seal and the output shaft, Figure 2

8.Check the direct clutch cylinder for groove marks on the inner ID of the drum, Figure 3.

aodgroove marks on the inner ID of the drum.gif

Figure 3 - Article 93-23-18

a.Groove marks indicate that the small cast iron rings are turning with the output shaft and grooving the cylinder.

b.Groove marks may also be caused by contamination or burrs in the output shaft seal ring grooves, causing the seal rings to turn with the output shaft.

c.Check the seal ring grooves carefully. replace the output shaft, seal rings and/or cylinder as required, and/or replace the case if the output shaft seal bore is grooved.

DIAGNOSTIC PROCEDURE NO. 2 - SLIPPING IN 4TH GEAR

NOTE: A BURNT OVERDRIVE BAND WILL HELP TO CONFIRM LEAKAGE IN THE OVERDRIVE CIRCUIT. REPLACING ONLY THE OVERDRIVE BAND WITHOUT FINDING THE CAUSE WILL RESULT IN A REPEAT REPAIR. IF THE OVERDRIVE BAND IS NOT BURNT, THE TORQUE CONVERTER DAMPER/HUB WELD MAY BE SUSPECT.

1.Check the overdrive servo cover O-rings and servo piston seal for possible leakage. Replace the O-rings and seal if leakage is evident.

2.Make sure that the overdrive servo cover is not porous:

a.Coat cover with fluid.

b.Apply air to overdrive servo apply passage using Servo Piston Remover T80L-77030-B or Transmission Test Plate T82L-7006-A.

c.Observe to see if air bubbles are present on overdrive servo cover.

3.Check the overdrive servo case apply passage to see if it is blocked (air pressure test). Replace the case if required.

4.Confirm that the overdrive band is seated correctly to the anchor pin.

5.Check the torque converter for damper/hub weld failure by performing the weld check procedure outlined in the Service Manual:

a.Use Torque Converter Checking Tool T83L-7902-A.

b.Replace the torque converter if shaft turns more than two (2) degrees, or if there is a grinding noise while applying 68 N-m (50 lb-ft) of torque.

6.Check splines on both ends of the direct drive shaft and in the direct clutch cylinder for damage/wear.

DIAGNOSTIC PROCEDURE NO. 3 - NO 3-4 UPSHIFT WITH DIRECT CLUTCH PRESSURE DIFFERENCE LESS THAN 15 PSI (110 kPa) - (indicates no leakage in direct clutch circuit)

1.Clean the valve body:

a.Check for a "sticking" condition at the following valves:

•Overdrive servo regulator valve

•3-4 shift valve

•3-4 TV modulator valve

•Orifice control valve

b.If any valves are sticking and cannot be free, replace the valve body.

2.Reduce the valve body bolt torque to minimum specification, i.e. 9 N-m (80 lb-in).

3.Check the fit of the governor counterweight on the output shaft. If the fit is sloppy, replace the counterweight.

4.Check the governor-to-output shaft retaining ring to make sure it is properly seated on the output shaft; service as required.

5.Check the last two large seal rings on the output shaft (#9, #10), Figure 2.

a.The seal rings should move freely on the output shaft.

b.Check for metal or other contamination or burrs between the seal and the output shaft; replace the seals and/or output shaft as required.

6.Check the seal ring bore at the rear of the case for scoring. Light scoring is permissable, but deep grooving indicates case wear. Replace the case if deep grooving is found, Figure 4.

aoddeep grooving is found, Figure 4..gif

 
OP
OP
T

Thumper22866

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Ok, haven't done a diagnostic check yet, will do this weekend, but thought i'd give you abit more information. The motor, ECM and tranny have come off a 1991 bronco, while the rear diff is off a 1988 bronco, the gears have been changed to 4.56. After your initial reply I did a visual inspection of tranny and there is no TV cable attached to tranny, I have a lever for gear shift and that is it. I had a mechanic swap the tranny's is it possible he forgot to attach the TV cable ?, and if so is that where my problem lies ? The AOD tranny was completely rebuilt prior to installation. Ok have been doing research online and I believe this may be the E4OD tranny. Please advise me on how I can tell for sure, thanx

 
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miesk5

96 Bronco 5.0
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yo Thumper.

some E4OD, AOD & C6 Pan Identification & Driver Side pics;

by Kenneth at http://www.technicalvideos.com/identify_my_transmission.phtml

E4OD have 20 pan bolts; P-R-N-D-2-1 shifter pattern

picture-011.jpg

pic by Chris A

AOD have 14 pan bolts, see diagram & pic; P-R-N-(D)-D-1 shifter pattern, note, OD is actually a (D) - pic by trigger @ http://img.photobucket.com/albums/v663/RampageFSJ/a4-1.jpg

C6 have 17 pan bolts, see diagram & pic; P-R-N-D-2-1, shifter pattern - pic by miesk5

http://www.broncolinks.com/gallery_images/C6ShiftIndicatorpic.JPG

=============

If E4OD, WAG;

Manual Lever Position/Transmission Range (MLPS/TR) Sensor - E4OD Controls Overview, Sensors, DTC (s) & Diagram; "...

Located on driver's side of transmission

The powertrain control module sends voltage to the Transmission Range (TR) sensor. The TR sensor incorporates a series of step-down resistors which act as a voltage divider. The powertrain control module monitors this voltage which corresponds to the position of the gearshift selector lever (P, R, N, (D), 2 or 1). The powertrain control module uses this information to determine the desired gear and electronic pressure control pressure. The TR sensor is located on the outside of the transmission at the gearshift selector lever. Harsh engagements, firm shift feel. DTC 634, 654, 667, 668, P0705, P0707, P0708, P1705

Nagging Neutral Nonsense & Pinpoint Test, Manual Lever Position (MLPS) also called Transmission Range (TR) Sensor. "...One of the most-difficult problems to diagnose on a Ford car or truck is a sudden neutral condition while the vehicle is cruising in 4th gear. Now this can have a number of causes, depending on which transmission is in the car or truck, but the cause we are going to discuss here is that #(~! *&A% Manual Lever Position Sensor – that’s right, the old MLPS. This sensor is responsible for more malfunctions than any other sensor in the system, and the kicker is that it seldom stores a code 67 or 634. Actually there is a standing joke in our industry that says, “You got a problem with a Ford, change the MLPS; it fixes everything,” which ain’t that funny because it’s not that far from the truth. Some of the problems the MLPS can cause are wrong gear starts, TCC hunting, no 4th gear, engine stalling, high or erratic line pressure and the problem that this article is about – a sudden neutral conditionSee Diagrams & instructions

Source: by Pete L at http://www.transonline.com/transdigest/magazines/1998-10/Shift%20Pointers/index.html

Some pull carpet or mat to accessit

To check MLPS

1. Hook red lead of DVOM to pin # 199 (MLP sensor signal).

2. Hook black lead of meter to pin 359 (sensor signal return).

3. Set meter to ohms.

4. Move manual lever through the different positions and compare DVOM reading to chart below.

Manuel lever position

Meter should read:

P 3769 to 4608 ohms

R 1304 to 1593 ohms

N 660 to 807 ohms

D 361 to 442 ohms

2 190 to 232 ohms

1 80 to 95 ohms

Important

If the MLPS needs replacement, use Ford part # E5TZ-7A247-A. This kit includes a new style harness connector. You must replace the connector to use the new MLPS. By sliding the old wire separator from the original connector up the harness you can leave it in place as you install the new connector. This helps to keep the wires in their original location.

Note

Make sure you clean the harness connector with brake clean and apply some dielectric grease to the pins. This will ensure a good connection. Use Permatex part # 67V (dielectric tune-up grease). You can get it at most auto parts stores.

 

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