Issue Summary:
- Leaving out an oil dam during assembly causes a leak from the front-seal area of a ZF 5HP24.
- A BMW or Jaguar with a ZF 5HP24 may come into the shop with a complaint of a neutral condition when the vehicle is coming to a stop when hot or a chatter on forward takeoff.
- Before or after overhaul, a 2003-04 Range Rover equipped with the ZF 5HP24 may exhibit a complaint of late shifting or neutralizing during highway driving.
- Dimensional differences can cause assembly problems during replacement of the input sun gear and/or thrust bearings in a 45RFE or 545RFE.
After overhaul and road testing, the vehicle is put on the lift for a final leak check. A leak is discovered coming from the front-seal area.
The transmission is removed to get a better look at the front seal. Upon inspection, the seal looked good and the snap ring that keeps the seal in was in place (Figure 1). A new seal was installed and the transmission was reinstalled into the vehicle. Within a few minutes of starting the engine, the leak in the front-seal area began again.
The front-seal oil dam that is directly behind the front seal was left out. The oil dam prevents ATF from flooding the front-seal area and causing it to leak.
Install the oil dam as shown in Figure 2; make certain the entire area has been cleaned and that the oil dam floats freely.
- Front-seal oil dam . . . . . . . . . ZF part number 0501-316-234
A BMW or Jaguar may come into the shop with a complaint of a neutral condition when the vehicle is coming to a stop when hot or a chatter on forward take-off. Code P0731 or Jaguar code P1722 may be stored for “Gear Ratio Error In First.”
High line pressure causes a crack to develop in the upper valve body (Figure 3) in the F-clutch circuit (Figure 4), which results in a loss of F-clutch oil. The F clutch is on in park, reverse and neutral and in manual low as shown in the clutch-application chart in Figure 5.
The complaint of neutral at a stop affects forward movement yet does not affect reverse because the F clutch is fed in park and neutral by the F-clutch valve but in reverse is fed line pressure through the reverse valve (Figure 4).
The reason first gear is affected is that oil pressure is being supplied to the closed F-clutch valve through the hydraulic circuit that is affected by the crack from shift valve 1 (Figure 4). This circuit is connected to the A clutch in first gear only.
So the loss of pressure going to the F-clutch valve is enough to cause the A clutch to release at engine idle speed when hot and slip the clutch on initial take-off; hence, the first-gear ratio codes, and the remaining forward gears will not be affected.
Replace the upper valve body and install the updated pressure-regulator valve (if the pressure-regulator bore is worn, valve-body replacement will be necessary).
- Pressure-regulator-valve update. . . . . . . ZF # 1058 327 030
- Upper-VB casting number 1058 427 059. . . . . . . . . . . . ZF # 1058 327 059
- Upper-VB casting number 1058 427 068.. . . . . . . . . . . . ZF # 1058 327 068
Before or after overhaul, a 2003-04 Range Rover equipped with the ZF 5HP24 transmission may exhibit a complaint of late shifting or neutralizing during highway driving. The driver may notice the “Transmission Overheat” message being displayed on the instrument cluster.
One cause may be restricted cooling channels in the radiator; in particular, the “lower eight tubes that supply coolant to the transmission cooler.”
A Technical Service Bulletin TSB No. LTB00080 Issue: 1 from Land Rover addresses this condition. The bulletin says that because of “Depletion of the coolant corrosion inhibitor,” a cooler restriction may result, causing the transmission to overheat.
If the transmission control module (TCM) detects ATF temperature above a preprogrammed threshold on this vehicle, it will use a shift strategy designed to cool the transmission to a level that is within normal operating temperatures. The TCM does this by significantly increasing the speed of the shifting points to maintain optimum engine speed and cooling. As a result of these increased shifting points, the technician may notice very late upshifts when starting off or may feel the transmission downshift to fourth, third or even second gear (second gear at highway speeds will be overrun and may feel like a neutral condition), depending upon the TCM’s interpretation of transmission temperature.
Since the TCM detects ATF temperature through input from the ATF-temperature sensor, it is plausible that a faulty ATF-temperature sensor or shorted wiring of the sensor could be responsible for the condition.
If the “Transmission Overheat” message is being displayed on the instrument cluster, it will be necessary to check the radiator for sufficient flow/drain rate. Use the “coolant-flow-rate test” that follows to check for sufficient flow/drain rate.
Note: Refer to factory TSB No. LTB00080 for diagram assistance.
If the transmission does not appear to be overheated, check the ATF-temperature sensor using the chart provided in Figure 6. If the resistance is not correct according to the chart, replace the internal harness as necessary.
Coolant-Flow-Rate Test:
- Set the heater control to warmest setting.
- Raise vehicle on a suitable lift.
- Disconnect the negative battery cable
- After cooling system has cooled to a workable temperature, remove the cap from the coolant expansion-tank reservoir. Note: Do not remove the cap from the coolant expansion-tank reservoir while the coolant is hot; burn injury may result.
- Remove the lower shield (front undertray) from the vehicle.
- Use a suitable clamp to close off the lower sub-cooler hose.
- Install a rubber tube to the radiator drain plug and place a catch container under the radiator below the tube to collect the coolant.
- Open the radiator drain plug all the way and collect about 8.5 ounces (250 milliliters) of coolant. Close radiator drain plug when the coolant has been collected. (Measure the amount of time needed to drain the coolant into the catch container.) According to factory TSB No. LTB00080, elapsed time to drain a new “unblocked” radiator is about 10 seconds. Drain time for a radiator with “confirmed blockage” on a vehicle that exhibits overheating symptoms is about 1 minute, 40 seconds.
- If evidence of blockage is apparent, replace radiator as necessary.
- If no evidence of blockage is apparent, add appropriate amount of coolant to top off the system, and replace the coolant expansion-tank reservoir cap. Further diagnostics of cooling-system overheating will be necessary.
There may be assembly problems when you are replacing the input sun gear and/or thrust bearings.
There are two dimensionally different input sun gears and two different reverse-planet to input-sun-gear bearings (Figure 7).
Both input sun gears have the same angle with 42 teeth, and each has an outer diameter of 2.650 inches.
One sun gear has an overall height of 2.065 inches, which includes a 0.142-inch lip with a bearing that is 0.150 inch thick and has an outer diameter of 2.360 inches (Figure 8).
The other input sun gear has a 0.085-inch lip with an overall height of 2.012 inches. The bearing has a 2.517-inch outside diameter and is 0.204 inch thick (Figure 8).
The two sun gears will interchange with each other as long as the input sun gear and the reverse-carrier to input-sun-gear bearing are used as a matching set.
August 2010 Issue
Volume 27, No. 8
- ZF 5HP24: Chronic front-seal leak
- ZF 5HP24: Neutralization; chatter
- 2003-04 Range Rover ZF 5HP24: Late shifts, neutralizing
- 45RFE & 545RFE: Assembly tip