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Amedee
Amedee, Dodge Technician
Category: Dodge
Satisfied Customers: 25029
Experience:  ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
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1995 dodge caravan: automatic..overdrive..Transmission wont shift

Customer Question

I have a 1995 dodge caravan 3.0 V6 automatic overdrive transmission. Transmission won't shift. fluid is clean and full. I have checked fuses and replaced trans shift control module (square box on fire wall passenger side) with used one from salvage yard. Still no shift not even manually. Electric plug to trans is clean and tight. What can I do next?Thanks, Larry
Submitted: 8 years ago.
Category: Dodge
Expert:  Amedee replied 8 years ago.

HEllo!

 

It sounds like the trans is shot. But I could be wrong. Just about all you can do is check the fluid level and the condition of the fluid (which you already did).

 

I suppose you could check line pressure or maybe even check for codes in the computer. But I am afraid to say, at this point in the game, I think the trans has went south.

 

 

Customer: replied 8 years ago.
Transmission had been working fine, fluid clean not burned. All of sudden stopped shifting. Seems to me it could be electrical problem of some sort. Do these transmissions have solenoids inside? Are they serviced by removing the pan? How can I find the problem? Thanks Larry
Expert:  Amedee replied 8 years ago.

Here is a picture of the shift solenoids.

 

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Expert:  Amedee replied 8 years ago.

Hydraulic Pressure Testing

 

Pressure testing can reveal the cause (not the symptom) of most transaxle problems. Hydraulic pressure testing verifies the proper functioning, or malfunctioning, of the following hydraulic components:


Oil pump
Regulator valve
Hydraulic circuits
Transaxle problems can be isolated to an electronic or hydraulic/mechanical component. The hydraulic pressure test is a helpful tool in determining whether the problem is electronic or hydraulic/mechanical.

Here are some general guidelines that apply to this procedure, as follows:


Verify proper fluid level and condition.
Verify and correct for proper gearshift linkage adjustment.
Verify that electrical connectors associated with the transaxle are properly connected and are clean and secure.
Allow the transaxle to reach operating temperature before testing.
Any of the above conditions, if not checked and/or corrected, can result in false readings and inaccuracies.



 

 

Expert:  Amedee replied 8 years ago.

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Expert:  Amedee replied 8 years ago.

GENERAL INFORMATION
Pressure testing is a very important step in the diagnostic procedure. These tests usually reveal the cause of most hydraulic transaxle problems.

Before performing pressure tests, be certain that fluid level and condition, and shift cable adjustments have been checked and approved. Fluid must be at operating temperature (150 to 200 degrees F).

Install an engine tachometer, raise vehicle on hoist which allows front wheels to turn, and position tachometer so it can be read.

Attach 150 psi gauges to ports required for test being conducted. A 300 psi gauge (C-3293) is required for reverse pressure test.

Test port locations are illustrated.

TEST ONE-SELECTOR IN LOW 1ST GEAR


Attach pressure gauge to the low/reverse clutch tap.
Move selector lever to the (L) position.
Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed to 20 mph.
Low/reverse clutch pressure should read 115 to 145 psi.
This test checks pump output, pressure regulation and condition of the low/reverse clutch hydraulic circuit and shift schedule.
NOTE: This test checks the underdrive clutch hydraulic circuit as well as the shift schedule.

TEST TWO-SELECTOR IN DRIVE 2ND GEAR


Attach gauge to the underdrive clutch tap.
Move selector lever to the 3 position.
Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 30 mph.
In second gear the underdrive clutch pressure should read 1 10 to 145 psi.
NOTE: This test checks the underdrive clutch hydraulic circuit as well as the shift schedule.

TEST 2A-SELECTOR IN OD


Attach gauge to the UD clutch tap.
Move selector lever to the OD position.
Allow wheels to rotate freely and increase throttle opening to achieve an indicated speed of 40 mph.
Underdrive clutch pressure should read below 5 psi. If not, than either the solenoid assembly or TOM is at fault.
TEST THREE-OVERDRIVE CLUTCH CHECK


Attach gauge to the overdrive clutch tap.
Move selector lever to the (Circle D) position.
Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 20 mph.
Overdrive clutch pressure should read 74 to 95 psi.
Move selector lever to the (3) position and increase indicated vehicle speed to 30 mph.
The vehicle should be in second gear and overdrive clutch pressure should be less than 5 psi.
This test checks the overdrive clutch hydraulic circuit as well as the shift schedule.
TEST FOUR-SELECTOR IN CIRCLE DRIVE, OVERDRIVE GEAR


Attach gauge to the 2/4 clutch tap.
Move selector lever to the (Circle D) position.
Allow vehicle front wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 30 mph.
The 2/4 clutch pressure should read 75 to 95 psi.
This test checks the 2/4 clutch hydraulic circuit.
TEST FIVE-SELECTOR IN CIRCLE DRIVE, OVERDRIVE


Attach gauge to the torque converter clutch off pressure tap.
Move selector lever to the (Circle D) position.
Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 50 mph. CAUTION: Both wheels must turn at the same speed.
Torque converter clutch off pressure should be less than 5 psi.
This test checks the torque converter clutch hydraulic circuit.
TEST SIX-SELECTOR IN REVERSE


Attach gauge to the reverse and LR clutch tap.
Move selector lever to the reverse position.
Read reverse clutch pressure with output stationary (foot on brake) and throttle opened to achieve 1500 rpm.
Reverse and LR clutch pressure should read 165 to 235 psi.
This test checks the reverse clutch hydraulic circuit.
TEST RESULT INDICATIONS


If proper line pressure is found in any one test, the pump and pressure regulator are working properly.
Low pressure in all positions indicates a defective pump, a clogged filter, or a stuck pressure regulator valve.
Clutch circuit leaks are indicated if pressures do not fall within the specified pressure range.
If the overdrive clutch pressure is greater than 5 psi in Step 4 of Test Three, a worn reaction shaft seal ring or a defective solenoid assembly is indicated.
If the underdrive clutch pressure is greater than 5 psi in Step 4 of Test 2A, a defective solenoid assembly or TCM is the cause.

 

 

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