Dodge Nitro. Manual — part 328

Fig. 11: Fluid Leakage Paths
Courtesy of CHRYSLER LLC

When diagnosing converter housing (5) fluid leaks, three actions must be taken before repair:

1. Verify proper transmission fluid level.

2. Verify that the leak originates from the converter housing area and is transmission fluid.

3. Determine the true source of the leak.

Fluid leakage at or around the torque converter area may originate from an engine oil leak (7). The area should

1 - PUMP SEAL
2 - PUMP VENT
3 - PUMP BOLT
4 - PUMP GASKET
5 - CONVERTER HOUSING
6 - CONVERTER
7 - REAR MAIN SEAL LEAK

2007 Dodge Nitro R/T

2007 AUTOMATIC TRANSMISSION 42RLE - Service Information - Nitro

be examined closely. Factory fill fluid is red and, therefore, can be distinguished from engine oil. See Fig. 11.

Some suspected converter housing fluid leaks may not be leaks at all. They may only be the result of residual
fluid in the converter housing, or excess fluid spilled during factory fill, or fill after repair. Converter housing
leaks have several potential sources. Through careful observation, a leak source can be identified before
removing the transmission for repair.

Pump seal (1) leaks tend to move along the drive hub and onto the rear of the converter. Pump o-ring or pump
body leaks follow the same path as a seal leak. Pump attaching bolt (3) leaks are generally deposited on the
inside of the converter housing (5) and not on the converter itself. Pump seal (1) or gasket (4) leaks usually
travel down the inside of the converter housing. See Fig. 11.

TORQUE CONVERTER LEAKAGE

Fig. 12: Outside Diameter Weld, Torque Converter Hub Weld, Starter Ring Gear & Lug
Courtesy of CHRYSLER LLC

Possible sources of torque converter leakage are:

Torque converter weld leaks at the outside diameter weld (1). See Fig. 12

Torque converter hub weld (2).

1 - OUTSIDE DIAMETER WELD
2 - TORQUE CONVERTER HUB WELD
3 - STARTER RING GEAR
4 - LUG

2007 Dodge Nitro R/T

2007 AUTOMATIC TRANSMISSION 42RLE - Service Information - Nitro

ROAD TEST

Prior to performing a road test, verify that the fluid level, fluid condition, and linkage adjustment have been
approved.

During the road test, the transmission should be operated in each position to check for slipping and any
variation in shifting.

If the vehicle operates properly at highway speeds, but has poor acceleration, the converter stator overrunning
clutch may be slipping. If acceleration is normal, but high throttle opening is needed to maintain highway
speeds, the converter stator clutch may have seized. Both of these stator defects require replacement of the
torque converter and thorough transmission cleaning.

Slipping clutches can be isolated by comparing the "Elements in Use" chart with clutch operation encountered
on a road test. This chart identifies which clutches are applied at each position of the selector lever.

A slipping clutch may also set a DTC and can be determined by operating the transmission in all selector
positions.

ELEMENTS IN USE AT EACH POSITION OF SELECTOR LEVER

The process of elimination can be used to detect any unit which slips and to confirm proper operation of good
units. Road test analysis can diagnose slipping units, but the cause of the malfunction cannot be determined.
Practically any condition can be caused by leaking hydraulic circuits or sticking valves.

Shift Lever

Position

INPUT CLUTCHES

HOLDING CLUTCHES

Underdrive

Overdrive

Reverse

2/4

Low/Reverse

P - PARK

-

-

-

-

X

R - REVERSE

-

-

X

-

X

N - NEUTRAL

-

-

-

-

X

OD - OVERDRIVE

-

-

-

-

-

First

X

-

-

-

X

Second

X

-

-

X

-

Direct

X

X

-

-

-

Overdrive

-

X

-

X

-

D - DRIVE*

-

-

-

-

-

First

X

-

-

-

X

Second

X

-

-

X

-

Direct

X

X

-

-

-

L - LOW*

-

-

-

-

-

First

X

-

-

-

X

Second

X

-

-

X

-

Direct

X

X

-

-

-

* Vehicle upshift and downshift speeds are increased when in these selector positions.

2007 Dodge Nitro R/T

2007 AUTOMATIC TRANSMISSION 42RLE - Service Information - Nitro

FLUID AND FILTER

DIAGNOSIS AND TESTING

EFFECTS OF INCORRECT FLUID LEVEL

A low fluid level allows the pump to take in air along with the fluid. Air in the fluid will cause fluid pressures to
be low and develop slower than normal. If the transmission is overfilled, the gears churn the fluid into foam.
This aerates the fluid and causing the same conditions occurring with a low level. In either case, air bubbles
cause fluid overheating, oxidation, and varnish buildup which interferes with valve and clutch operation.
Foaming also causes fluid expansion which can result in fluid overflow from the transmission vent or fill tube.
Fluid overflow can easily be mistaken for a leak if inspection is not careful.

CAUSES OF BURNT FLUID

Burnt, discolored fluid is a result of overheating which has two primary causes.

1. A result of restricted fluid flow through the main and auxiliary cooler. This condition is usually the result

of a damaged main cooler, or severe restrictions in the coolers and lines caused by debris or kinked lines.

2. Heavy duty operation with a vehicle not properly equipped for this type of operation. Trailer towing or

similar high load operation will overheat the transmission fluid if the vehicle is improperly equipped.
Such vehicles should have an auxiliary transmission fluid cooler, a heavy duty cooling system, and the
engine/axle ratio combination needed to handle heavy loads.

FLUID CONTAMINATION

Transmission fluid contamination is generally a result of:

Adding incorrect fluid.

Failure to clean dipstick and fill tube when checking level.

Engine coolant entering the fluid.

Internal failure that generates debris.

Overheat that generates sludge (fluid breakdown).

Failure to replace contaminated converter after repair.

The use of non-recommended fluids can result in transmission failure. The usual results are erratic shifts,
slippage, abnormal wear and eventual failure due to fluid breakdown and sludge formation. Avoid this
condition by using recommended fluids only.

The dipstick cap and fill tube should be wiped clean before checking fluid level. Dirt, grease and other foreign
material on the cap and tube could fall into the tube if not removed beforehand. Take the time to wipe the cap
and tube clean before withdrawing the dipstick.

Engine coolant in the transmission fluid is generally caused by a cooler malfunction. The only remedy is to
replace the radiator as the cooler in the radiator is not a serviceable part. If coolant has circulated through the
transmission, an overhaul is necessary.

2007 Dodge Nitro R/T

2007 AUTOMATIC TRANSMISSION 42RLE - Service Information - Nitro

2007 Dodge Nitro R/T

2007 AUTOMATIC TRANSMISSION 42RLE - Service Information - Nitro