LR3 RPM Fluctuation & Transmission Kick Before Stop
Hello. This is regarding a 2005 Land Rover LR3 HSE 4.4 with 234,000 miles (original engine and transmission).
Iím posting about a common issue with the ZF transmission found in the Land Rover LR3, full size Range Rover and the Range Rover Sport because although Iíve found many discussions about this problem on various forums - the problem never seems to be corrected on a long term basis.
At approximately 119,000 miles, I began to notice a slight RPM fluctuation (about 300 to 500 RPM's up and down) while traveling on a flat surface at approximately 25 to 35 MPH under constant throttle pressure. This problem is more pronounced during colder months and especially when the vehicle is still cold. The RPM revving also occurs while driving up slight inclines between 15 to 25 MPH.
It's important to note that the RPM fluctuation does not occur while in manual shift mode. Also, the car does not surge forward while the RPM's are revving.
At the same time, I began noticing a transmission kick just before coming to a complete stop. The LR3 seems to suddenly downshift and slightly surge forward at around 5 MPH just before coming to a complete stop. This is a very sporadic problem which occurs both in manual and automatic about 40% of the time. The problem is better described in the service bullet below.
There are no other issues with the transmission whatsoever. The two issues are simply an annoyance.
After some research, I concluded that is was likely the result of a faulty torque converter. But since there werenít and arenít any other issues with the transmission, Iíve opted not to replace the TC or the transmission. During the last few years and 115,000 miles the problem hasn't gotten any worse, but continues to be an annoyance. I always drive in manual shift mode while in the city.
Here is a list of all the work I've had done on the vehicle in an attempt to resolve the issue.
-The vehicle has no code fault errors.
-Throttle body assembly professionally cleaned.
-Replaced water pump due to another unrelated issue (curiously, others have claimed their RPM issue disappeared after replacing it).
-Transmission pan and filter replacement at approximately 160,000 miles.
-Transmission flush at 233,000 miles (all of the transmission fluid was removed with a transfusion and replaced).
-Fuel filter replacement.
-Fuel injector cleaning
-Replaced coil pack capacitor (diode)
Here is a list of fixes recommended on other threads that I have NOT attempted
1. Throttle position sensor.
2. No indication of an intake or vacuum leak.
3. Because the problem is more pronounced in cold conditions, some have claimed using a transmission fluid with a different viscosity solved the problem.
None of the above has rectified the problem. I was about to order a used transmission when Cory at RoverLandParts.com informed me that if the RPM fluctuation is an "electronic issue" in the transmission control module within the valve body assembly - it is conceivable I will have the same issue with a used transmission with a brand new torque converter as the existing "brain" will simply give the same faulty shifting information to the new (used or rebuilt) transmission. Cory recommends purchasing a remanufactured transmission with a new torque converter, valve body assembly, TCM, etc.
The question for all of you
Before I dump $5,000 into a remanufactured transmission, I am curious if anyone knows if it is possible to simply completely erase the TCM (brain) of the transmission or the cost to install a new one and if that's even possible without replacing the entire valve body assembly. Here's why. At approximately 130,000 miles, I had Land Rover Las Vegas reprogram the transmission, but the shifting and kick before the stop was much much worse. I turned around, they made another adjustment and it returned the condition it was in at the beginning of the day. However, because the reprogramming clearly affected the shifting, it seems like a proper reprogramming may fix the problem. However, my local Land Rover dealer strongly advised against reprogramming the TCM as they fear that the car may be inoperable since the transmission has over 233,000 miles on it. One of the options Iím now considering is to have them reprogram the transmission on the rare chance that it will work and finally order a new one if it results in the car being inoperable.
Any other suggestions or thoughts?
Hereís a Land Rover bulletin regarding the downshift kick
"Bulletin#LA307-002. SECTION: 307-01 Ė AUTOMATIC TRANSMISSION SYSTEM. Harsh Transmission Downshift (2nd to 1st)
AFFECTED VEHICLE RANGE: LR3 (LA) (4.4L AJV8 engine only) VIN: 5A000360 to 6A402253 CONDITION SUMMARY:
TRANSMISSION DOWNSHIFT FROM 2ND TO 1ST GEAR IS HARSH Situation: A customer may report a concern that the gearshift is harsh and results in a thump or bump when the transmission shifts from 2nd to 1st gear. This condition occurs when the throttle is applied following a deceleration where the vehicle is slowing to a near stop. This condition can be intermittent and can vary depending upon the amount of throttle that is applied.An automatic transmission software calibration issue may be the cause. NOTE: Service Action B036 Ė Tune Updates and Enhancement Repairs may apply and resolve this concern. DDW must be first checked to determine which vehicles within the affected VIN range of this bulletin require B036 to be completed in lieu of this bulletin. This bulletin is not to be completed or claimed if B036 is completed and claimed.
Refer to the latest issue of Technical Service Bulletin SB036 as applicable. Action: Should a customer express this concern, and B036 does not apply, verify the condition and refer to the Repair Procedure detailed in this bulletin to update the control module software. PARTS: No parts required. TOOLS: IDS DVD 102 with Patch File 3 (or later software) installed.
or WDS CD13 with Patch File 8 (or later software) installed."