Hello. This is regarding a 2005 Land Rover LR3 HSE 4.4 with 234,000 miles (original engine and transmission).=start
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I’m 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 I’ve found many discussions about this problem on various forums - the problem never seems to be corrected on a long term basis. =start
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 weren’t and aren’t any other issues with the transmission, I’ve 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.
=startHere is a list of all the work I've had done on the vehicle in an attempt to resolve the issue. =start-The vehicle has no code fault errors. =start
-Throttle body assembly professionally cleaned.
=start-Replaced MAF.
=start-Replaced water pump due to another unrelated issue (curiously, others have claimed their RPM issue disappeared after replacing it).=start-Transmission pan and filter replacement at approximately 160,000 miles.
=start-Transmission flush at 233,000 miles (all of the transmission fluid was removed with a transfusion and replaced). 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 I’m 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?=start

 

If you have the IID tool, you could try re-flashing the TCM, that way you can avoid the dealer's exorbitant fees for doing it, and even if it doesn't work, you have a great diagnostic and maintenance tool for your rover (if you keep it). I'd do your research very thoroughly before doing a re-flash, however, as it can make a transmission behave worse just as easily as it can fix it. Did you change your fluid and filter at the ZF recommended 75k miles or the LR recommended 135k?

 

I have this exact same issue, the rpm fluctuations drive me crazy.

 

There is two schools of thought on the issue for the rpm fluctuation. The torque converter is the issue or the solenoid valve block thing (real name is eluding me right now).

 

Thanks for the reply. Yes, the fluid and filter were changed. I'm considering re-flashing the TCM with the IID tool, but I'm going to do it near the mechanic in the event it renders the LR3 inoperable as the dealership has warned.

 

Yes, it does appear to be either the torque converter or the valve body assembly (is that the term you were looking for)?

 

A quick update. I replaced ignition coil (coil capacitor), had the throttle body professionally cleaned and performed a full transmission flush or transfusion (the oil alone was $425). The RPM fluctuation and downshift "kick" just before the stop persist.

After the transmission flush was performed, neither problem was noticeable for about 30 minutes. I began to think the problem was resolved, but minutes later felt a very very subtle downshift kick just before a stop. During the next few hours, the RPM fluctuation and downshift kick become more and more harsh and noticeable to exactly where it was before the flush was performed.

Since the transmission control module (TCM) is a part of the valve body assembly, it cannot be replaced separately. The only way to replace the TCM is to buy a new valve body assembly for about $2,400 from a Land Rover dealer. The problem is that if the problem is the torque converter, I will have wasted over $3,200 having a valve body assembly installed.

I'm left with only two options. Buy a remanufactured or new transmission with a new valve body assembly and torque converter or to continue to live with the annoyance.

 

Did you do the TCM re-flash? It's not as terrifying as it sounds. The only botched re-flash that can really brick the car is the BCM. If you're unhappy with the transmission's behavior as-is, you don't have much to lose by re-flashing it. If it's the torque converter or valve body, it may get worse after the re-flash, or it may not. If it's the software, it'll be fixed. That way you're sure. Way cheaper than replacing expensive parts and hoping for the best.

Pull your other Land Rover (everyone has two) out into the driveway and hook jumper cables up as if you're going to jump the car you're doing the re-flash on. Start the other Rover and let it run for a minute, then do the re-flash. This way there's no way your battery can run dead during the flash as you're basically running off the alternator of the other car (as long as the other car has a good alternator :P).

 

Since I am still sorta new to Rovers and LR3, this is a little over my head. But can't the IID Tool display solenoid information? Would that not help show a solenoid, say for the TC, fluctuating or drawing too much power? Also I am going to add, that if this was any other vehicle I would suspect a vacuum leak over the transmission. False engine data can really mess up how a transmission reacts, so just for the heck of it have you observed the live data of the O2 sensors?

 

It sounds like your issue is slightly different, but I'll throw this out there. My RPM used to dip upon coming to a stop (last few MPH), accompanied by a slight vibration and return to smooth idle. Worse when cold. New spark plugs fixed it. It felt like a transmission issue but wasn't. I think I read a post here or somewhere to that effect, and it is also consistent with what Dakota mentions as well regarding engine health affecting shifting. How old are your plugs?