Mercedes-Benz Sprinter / Dodge Sprinter. Service manual — part 436

DIAGNOSIS AND TESTING

AUTOMATIC TRANSMISSION

CAUTION: Before attempting any repair on a NAG1
automatic transmission, check for Diagnostic Trou-
ble Codes with the appropriate scan tool.

Transmission malfunctions may be caused by these

general conditions:

• Poor engine performance.
• Improper adjustments.
• Hydraulic malfunctions.
• Mechanical malfunctions.
• Electronic malfunctions.
• Transfer case performance (if equipped).
Diagnosis of these problems should always begin

by checking the easily accessible variables: fluid level
and condition, gearshift cable adjustment. Then per-
form a road test to determine if the problem has been
corrected or if more diagnosis is necessary.

PRELIMINARY

Two basic procedures are required. One procedure

for vehicles that are drivable and an alternate proce-
dure for disabled vehicles (will not back up or move
forward).

VEHICLE IS DRIVABLE

(1) Check for transmission fault codes using the

appropriate scan tool.

(2) Check fluid level and condition.
(3) Adjust gearshift cable if complaint was based

on delayed, erratic, or harsh shifts.

(4) Road test and note how transmission upshifts,

downshifts, and engages.

VEHICLE IS DISABLED

(1) Check fluid level and condition.

(2) Check for broken or disconnected gearshift

cable.

(3) Check for cracked, leaking cooler lines, or loose

or missing pressure-port plugs.

(4) Raise and support vehicle on safety stands,

start engine, shift transmission into gear, and note
following:

(a) If propeller shaft turns but wheels do not,

problem is with differential or axle shafts.

(b) If propeller shaft does not turn and transmis-

sion is noisy, stop engine. Remove oil pan, and
check for debris. If pan is clear, remove transmis-
sion and check for damaged driveplate, converter,
oil pump, or input shaft.

(c) If propeller shaft does not turn and transmis-

sion is not noisy, perform hydraulic-pressure test to
determine if problem is hydraulic or mechanical.

ROAD TESTING

Before road testing, be sure the fluid level and con-

trol

cable

adjustments

have

been

checked

and

adjusted if necessary. Verify that all diagnostic trou-
ble codes have been resolved.

Observe engine performance during the road test.

A poorly tuned engine will not allow accurate analy-
sis of transmission operation.

Operate the transmission in all gear ranges. Check

for shift variations and engine flare which indicates
slippage. Note if shifts are harsh, spongy, delayed,
early, or if part throttle downshifts are sensitive.

Slippage indicated by engine flare, usually means

clutch, overrunning clutch, or line pressure problems.

A slipping clutch can often be determined by com-

paring which internal units are applied in the vari-
ous gear ranges. The Clutch Application chart
CLUTCH APPLICATION provides a basis for analyz-
ing road test results.

CLUTCH APPLICATION

GEAR

RATIO

B1

B2

B3

K1

K2

K3

F1

F2

1

3.59

X*

X

X*

X

X

2

2.19

X

X

X*

X

3

1.41

X

X

X

4

1.00

X

X

X

5

0.83

X

X

X

X*

N

N/A

X

X

R

3.16

X*

X

X

X

R - Limp In

1.93

X

X

X

* = The shift components required during coast.

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AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION

21 - 39

AUTOMATIC TRANSMISSION

CONDITION

POSSIBLE CAUSES

CORRECTION

MAXIMUM SPEED 30
km/h

1. Speed Control 30 Actuated.

1. Instruct Customer.

ENGINE DIES WHEN

TRANSMISSION IS SHIFT-

ED INTO GEAR, ALSO

NOISES IN N AND/OR P

1. PWM Valve Blocked.

1. Replace Valve.

2. Torque Converter Lock Up Con-
trol Valve Locked.

2. Enable Movement of Valve,
Remove Particle.

LEVER IN “P” POSITION

BLOCKED (BRAKE ACTI-

VATED)

1. No Vacuum Brake Booster After
Long Immobilization, Brake Pedal
Not Fully Applied/Hard Pedal.

1. Check Vacuum/ Tightness of
Brake Booster.

2. No Stoplamp Switch Signal (no
DTC IN ECM).

2. Check Contact to Stoplamp
Switch. Replace Switch if Nec-
essary.

GRUMBLING, DRONING,

JERKING WHEN TCC IS

ENGAGED

1. Slip Speed TCC to Low.

1. Switch Off Torque Converter
Lock Up Using DRB

T

. If Com-

plaint Is Not Reproduced After-
wards, Replace PWM Valve,
Set Adaption Values to Zero.

HOWLING, HUMMING

ABOVE 4000 RPM IN

EACH GEAR

1. Oil Filter Blocked.

1. Replace Oil Filter.

2. Oil Pump.

2. Replace Oil Pump.

WHINING, SINGING

1. Gear Set Noises in 1st, 2nd, 5th
Gear.

1. Replace Transmission..

2. Intermediate Bearing Of The
Drive Shaft At 0 km/h, Only When
Cold.

2. Replace Intermediate Bear-
ing of the Drive Shaft.

9

CLACK” NOISE FROM

CENTER SHIFT AREA

WHEN STOPPING OR

STARTING

1. Park Lock Solenoid.

1. Replace Shift Lever Assem-
bly.

CRACKING NOISE WHEN

LOAD CYCLE

1. Stick - Slip Between Joint Flange
and Collar Nut.

1. Install Zinc Coated Collar
Nut Together With Washer.

CHATTERING IN CENTER

CONSOLE SHIFT WHILE

ACCELERATING

1. Bushing Shift Shaft Has Too
Much Clearance.

1. Replace Shifter Lever and
Cover Plate.

HARD 2-3 UPSHIFT

WHEN STEPPING OFF

THE ACCELERATOR PED-

AL

1. Response Characteristic Control
Loop.

1. Install K2 Disc Spring.

UPSHIFT 2-3, 3-4 SLIP-

PING

1. Spring of Regulating Valve Pres-
sure control Valve Broken.

1. Replace Spring.

HARD 2-1 DOWNSHIFT

WHEN COMING TO A

STOP

1. Transmission (2-1 downshift) Not
Adapted.

1. Re-adapt Transmission.

2. TCM Software Data.

2. Flash TCM.

3. Free Wheeling Clutch F1 Defec-
tive.

Replace Free Wheeling Clutch
F1.

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AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION

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CONDITION

POSSIBLE CAUSES

CORRECTION

HARD 3-2 DOWNSHIFT
WHEN DECELERATION

EVEN AFTER READAP-

TION

1. K3 Idles.

1. Install TCM And/Or Electro-
hydraulic Control Unit.

NO RESP. DELAYED UP-

SHIFT, NO DTC

1. Different Tire Sizes Are Mounted
On The Front Axle.

1. Mount Uniform Tire Sizes
On The Front Axle.

NO UPSHIFT 3-4, 4-5 AF-

TER FAST OFF (ACCEL-

ERATOR)

1. Upshift Prevention To Realize Dy-
namical Drivestyle.

1. Instruct Customer.

NO UPSHIFT OF 1ST

GEAR BELOW 5000 RPM

1. Gear Recognition Switch.

1. Replace Gear Recognition
Switch.

NO UPSHIFT INTO 5TH

GEAR WHEN FULL

THROTTLE OR KICK

DOWN ACTIVATION

1. The Upshift 4-5 At Full Throttle or
Kick Down Never Occurs Until
Reaching Cut Off Speed. Under
These Conditions, The High Pow-
ered Vehicle Will Never Shift Into
5th Gear Below 250 km/h.

1. Instruct Customer.

NO KICK DOWN SHIFT-

ING

1. Accelerator Pedal Value < 95%.

1. Check Engine Control. Ad-
just As Necessary.

Engine Turns Up While 2-3

Upshift and/or Hard 3-2

Downshift

1. Oil Level Too Low.

1. Check Oil Level. Add if Nec-
essary.

2. Oil Filter Not Installed.

2. Install Oil Filter.

3. Free Wheeling Clutch F2 Defec-
tive.

3. Replace Free Wheeling
Clutch F2, Hollow Shaft, and
Rear Sun Gear/Inner Disc Car-
rier K3.

GRABBING 2-3 COAST-

ING UPSHIFT AND/OR

BRAKE DOWNSHIFT

1. Oil Level Too Low.

1. Check Oil Level. Add if Nec-
essary.

2. Oil Filter Not Installed.

2. Install Oil Filter.

3. Control shift or Command Valve
Blocked.

3. Check Each Slide Valve For
Base Position and Ease Of
Movement, Remove Particle.

4. K3 Disc Burnt, Hot Spots or
Rubbed Down.

4. Replace Inner and Outer
Disc Carrier K3 And Control
Valve.

DELAYED ENGAGEMENT,

NO TRANSFER OF POW-

ER IN R AND/OR D, ALSO

AT TIMES

1. Oil Level Too Low.

1. Check Oil Level. Add if Nec-
essary.

2. Recognition Switch - Selector Le-
ver Position.

2. Replace Recognition Switch
Only When Intermediate Posi-
tion or Fault is Indicated.

3. Oil Filter Not Installed.

3. Install Oil Filter.

4. AEV, Delayed Pressure Build Up
On Piston B2/B3.

4. Install New Shifting Proce-
dure (TCM, electrohydraulic
control unit or repair set).

5. Wrong Combination TCM/Electro-
hydraulic Control Unit.

5. Check Combination TCM/
Electrohydraulic Control Unit.
Replace TCM Resp. Electrohy-
draulic Control Unit, if neces-
sary.

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AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION

21 - 41

CONDITION

POSSIBLE CAUSES

CORRECTION

NO UPSHIFT OF 1ST

GEAR AT TIMES

1. Connector Ballast Unit. Output
Speed Sensor Loose, Incorrectly
Contacted.

1. Check Connectors, Replace
Output Speed sensor If Neces-
sary.

2. Output Speed Sensor Defective

2. Replace Output Speed Sen-
sor.

LEAKAGE AT THE AREA

OF THE ELECTRICAL

PLUG TO THE CONDUC-

TOR PLATE

1. Deformation O-Rings.

1. Replace O-Rings.

2. Deformation Adapter.

2.Replace Adaptor.

3. The Conductor Plate Is Not Fitted
Surface To Surface On The Valve
Body In One Corner, The Plug Is
Not Centered In The Socket And
The O-ring Will Not Seal.

3. Remove Nose Of Conductor
Plate.

4. Contacting At The Conductor
Plate Leaky. Oil In Harness, Some-
times In The Control Module.

4. Replace Conductor Plate.

LEAKAGE AT THE AREA

OF BELL HOUSING/

TORQUE CONVERTER

1. Bolts (Torx M6) Outer Disc Carri-
er B1.

1. Clean Thread and Install the
Bolts Using Sealer.

OIL LEAKS

1. 6 Lower Bolts (TorxM8) Converter
Housing.

1. Clean Thread and Install the
Bolts Using Sealer.

2. Oil Drain Plug Converter Loose
Resp. No Seal Ring Installed.

2. Install Drain Plug Correctly.

3. Weld Seam Of Torque Converter
Leaky.

3. Replace Torque Converter.

4. Radial Sealing Ring Oil Pump
Defective.

4. Replace Sealing Ring.

5. O-Ring Oil Pump Defective Or
Not Installed.

5. Install O-Ring.

6. Bushing Of Oil Pump Loose,
caused By Missing Fit Bolt At
Transmission/Engine Flange.

6. Install Fit Bolt If Necessary.

STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR

Damaged or worn threads in the aluminum trans-

mission case and valve body can be repaired by the
use of Heli-Coils™, or equivalent. This repair con-
sists of drilling out the worn-out damaged threads.
Then tap the hole with a special Heli-Coil™ tap, or
equivalent, and installing a Heli-Coil™ insert, or
equivalent, into the hole. This brings the hole back to
its original thread size.

Heli-Coil™, or equivalent, tools and inserts are

readily available from most automotive parts suppli-
ers.

REMOVAL

(1) Disconnect the negative (ground) battery cable.

CAUTION: Isolate ground lead to prevent accidental
contact.

(2) Apply parking brake.
(3) Move gear selector lever to position “N”.
(4) Remove oil drain plug (2) (Fig. 26) and drain

automatic transmission oil into a clean container.

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AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION

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