Problems with reverse and vehicle will not go over thirty mph

Hi,

It could be a few things. Is the fluid clean and full?

Here are the directions for checking fluid level and condition. Do this and let me know the results. The attached picture correlates with the directions.

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2005 Jeep Truck Liberty 4WD V6-3.7L VIN K
Fluid Level and Condition Check
Vehicle Maintenance Fluids Fluid - A/T Service and Repair Procedures Fluid Level and Condition Check
FLUID LEVEL AND CONDITION CHECK
DIAGNOSIS AND TESTING

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/or 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.

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.

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.

The torque converter should be replaced whenever a failure generates sludge and debris. This is necessary because normal converter flushing procedures will not remove all contaminants.

FLUID LEVEL CHECK
The transmission sump has a dipstick to check oil similar to most automatic transmissions. It is located on the left side of the engine. Be sure to wipe all dirt from dipstick handle before removing.

The torque converter fills in both the PARK and NEUTRAL positions. Place the selector lever in PARK to be sure that the fluid level check is accurate. The engine should be running at idle speed for at least one minute, with the vehicle on level ground. At normal operating temperature (approximately 82° C. Or 180° F.), The fluid level is correct if it is in the HOT region (cross-hatched area) on the oil level indicator. The fluid level should be in COLD region at 70° F fluid temperature. Adjust fluid level as necessary. Use only Mopar (R) ATF + 4, Automatic Transmission Fluid.

FLUID LEVEL CHECK USING SCAN TOOL

NOTE: Engine and Transmission should be at normal operating temperature before performing this procedure.

1. Start engine and apply parking brake.
2. Connect scan tool and select transmission.
3. Select sensors.
4. Read the transmission temperature value.
5. Compare the fluid temperature value with the chart.

See Pic 1

6. Adjust transmission fluid level shown on the dipstick according to the 42RLE Fluid Temperature Chart (Fig. 157). Use only Mopar (R) ATF + 4, Automatic Transmission Fluid.
7. Check transmission for leaks.

Nominal oil level in the vehicle

Let me know the results.

Joe

The 42RLE transmission in the Liberty is somewhat prone to failures. They can show up as random issues that go away, then they get more persistent. The problem you had is one of the early signs of either sensor or solenoid issues. The transmission went into limp mode where it limits the speed to 30-45 mph. To see why it went into limp mode requires a good scan tool that can read the transmission control module. A common reason is corroded connections or grounds.