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2010-2012 Range Rover MkIII / L322
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Discussion Starter #1
Hi all, I am experiencing a bit of hard shifting when I take off in the morning. I understand the first gear is held a bit longer when cold but when it shifts to 2nd sometimes it is a bit of a hard shift.

Do you guys have a similar experience?
FYI I just did a transmission oil drain and fill. It was dirty at 76k miles, I hope things improve for me.

Thanks in advance
 

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Have the transmission parameters reset with something like an IIDTool or have an indy LR shop do it. Unsure if dealerships will do it.

After this, drive your truck how you would normally.

Did you replace your filter? You should replace it at 80k miles according to ZF with ONLY a genuine ZF filter. I bought mine on eBay for around $90 shipped IIRC.
 

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2007 HSE
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I had a somewhat similar issue after drain/refill at local Ford dealer (Ford makes/uses variant of ZF's 6HP26 in F150's and some Ford parts are common with 6HP26). I'd planned another drain/refill, so when I took it back in the thought was maybe they didn't put enough fluid in during refill. After second drain/refill, all ran smoothly. Worth a shot...
 

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Technically in a drain-fill only around 40% of the transmission fluid is replaced, more new fluid better it shifts (of course unless something else is going on).

Use Mercon SP fluid from Ford, I bet that is what rfdiii did.
 

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I am guilty of using Mercon SP (I don't necessarily advocate it for others, but I have not had any problems with it).

I was at the Ford dealer again this morning for another vehicle (oil change / put on snow tires) and mentioned the now smooth-shifting transmission. To them, it sounded as if there was air/not enough fluid in the transmission. I speculate that when they did the refill they did not replace enough, or didn't completely follow the refill procedures to ensure fluid was throughout the tranny before closing it up.
 

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Mercon SP IS Lifeguard 6. It is within 2% difference, and I believe that is simply because it is manufactured in a different location than LG6.
 

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2010-2012 Range Rover MkIII / L322
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Discussion Starter #7
Hi, I wanted to post an update. I did two drains and fills in order to get out as much older fluid as possible. After driving the car for a few hundred miles, I can say the hard shifting on the second gear when cold has smoothed out. Now it feels like it a takes a bit longer to perform the shift, but it could be just me.
Once warmed up after 20-30 min driving or so the shiftings are imperceptible.

One more thing, I talked to ZF USA, and the guy there discouraged me from resetting the adaptive values after the draining.

I am still not happy with the way the car behaves. When I compare the shifting of our LR4 to my RRSC, the LR4 shift very smooth from the very get-go. I can't even tell when it is shifting.

Anyone, any ideas? Thanks in advance.
 

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..... I talked to ZF USA, and the guy there discouraged me from resetting the adaptive values after the draining....
The idea of the long-term adaptions is to allow the transmission controller to compensate for changes in the clutch performances over the whole life of the vehicle. The adaptions allow the solenoid currents to be incrementally ramped up (or down) over a long period of time (i.e. years) to ensure that the shift times remain constant and therefore the shift energies seen by the clutch packs remain within spec. while compensating for wear. The issue that wasn’t foreseen by ZF is that the six proportional pressure solenoids in the mechatronic unit have turned out to be very problematic in the 6HP26 and the mechatronic controller ends up having to use the adaptions to try to compensate for the unreliability of the solenoids. Sometimes, therefore, the solenoids may be operating at the extreme ends of the adaption range to hide their faults.



If the transmission adaptions are then reset, and the fluid is also changed at the same time, the combination of the changed coefficient of friction and the much-reduced solenoid current can lead to a situation where the transmission cannot learn the new settings before the clutches slip to such an extent that they overheat and the transmission is then permanently damaged.



For that reason, Land Rover issued an instruction to their dealerships not to reset the adaptions at the same time as a fluid change. The change in friction coefficient is potentially even greater if a non-Land Rover workshop (or individual owner) decides to use any fluid other than Lifeguard Fluid 6, usually because it’s less expensive. Saving £30 may end up costing the owner £3000.

I’m not certain why people feel the need to reset the adaptions anyway (unless, of course, a new software revision is being installed). I wonder if this is sometimes because they believe that the controller has learnt the driving style of a previous owner or something? This is absolutely not the case. Driving modes and styles are cleared each time the engine is turned off and on again. Only the long-term adaptions are stored, which are essential to compensate for wear.

In summary, if your solenoids are performing to spec. and you reset the adaptions at the same time as changing the fluid then all should be fine. On the other hand, if one or more of the solenoids is at its adaption limit due to a fault, then resetting its adaption to ‘nominal’ may prevent it generating sufficient pressure to stop the clutch that it is controlling from burning up before it gets chance to find its new setting. Workshops that know this are understandably not prepared to take the risk of trashing a customer’s transmission.

Phil
 

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Discussion Starter #9
Hi Phil, thank you so much for your extended feedback. I wonder if my next step should be to replace the solenoids? By the way isn't my transmission the 6hp28? I think your feedback still stands for the 6hp28.

One last question, would you worry about the Mechatronic Seal Adapter at 76k miles?
0501 219 952 01.jpg

Thank you, Eris
 

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A question for Phil if i may. If the solenoids are changed will the transmission adjust to the new ones without causing damage to the clutches or would reprogramming be necessary. Our tranny with 205K kms has been showing a periodic noticeable downshift from second to first on coast. I have just cleaned the maf (it was quite dirty on one side) so will see if that has any possible bearing on the shift.
 
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