Fluctuating RPM's at constant throttle (throttle hunting, surging, gear hunting)

[Dandavies9]

Hey guys I’m a proud new owner of a lr4 2010 v8 190ks. I’m having the same issues with revs fluctuating. However it happens with mine in manual mode too and at pretty much all speeds. Doesn’t happen when idling though. It does seem to struggle selecting the right gear sometimes but isn’t too bad only going up steep hills it’s worse. I do plan on doing the transmission service(Atlantic British) and hope this fixes it but is there any other recommendations for me to do. Any help would be great

 

[renli3d]

I just had this exact issue with the fluctuating RPMS at 45-45MPH. I had done the metal pan conversion on my LR3 30K miles ago. at the time, i replaced all the ZF seals as well but did not replace the solenoids. I refilled with Ravenol ATF. 30K miles later, this problem shows up. I drained the fluid at the drain bolt and the fluid was very dark. I refilled with 1 bottle of Lubegard platinum and 1 tube of Shudder Fix. I topped it off with Ravenol ATF. Reset adaptations. Problem was fixed instantly and it hasn't returned. the shifting is actually much better than after the first tranny service.

 

[bbyer]

You may wish to refer to my post #16 back in 2019 when I had 357,000 km on my 3; it now has 473,000 km (294,000 miles).

I replaced the engine oil temperature sensor that is connected to the water temperature sensor that is connected to the computer that is connected to .... well you get the idea - the engine surged and the tranny hunted when cold. In brief, replacement of the oil temperature sensor located down beside the oil filter (4.4L V8) seems to have resolved the concern - has not returned anyway.

Post #16 has the part number and a few more details. Given regular oil changes, my ZF is still doing what a tranny is supposed to do.

 

[FRCI]

I had a LR3 which would fluctuate RPMs randomly as described, weather parked or driving it seemed to occur. In my case, close monitoring of the engine various sensors while driving allowed me to find a faulty temp sensor on the coolant manifold on the top of the engine. The temp sensor for the engine coolant was delivering the proper temp 99% of the time, then randomly, would deliver -40F as the temp to the computer which would then (I suppose) trigger a fuel map change, thus causing the RPMs to jump up and down briefly. None of this fluctuating was appearing on the vehicle instruments nor did it trigger a MIL or check engine light, probably because it was always very breif (less than 2 seconds). Replacing the $40 temp prob solved the problem.