Chris Oz

Hi there
We're out on a long road trip and towing a 7000 pound trailer. Over the last few days when towing the trailer i ve noticed some harsh, jerky downshifting from 4 to 3 when the vehicle is looking for more power e.g on hills, not necessarily under heavy acceleration. I can consistently make it happen at 1500 rpm, you'll get a hard downshift and then the engine revs up to 2000 rpm. Doesnt occur in any others or when shifting up. Seems to come and go a bit but is probably worse after an hour or so of driving. Also occurred today consistently without the trailer after about an hour of driving. I figured out i can avoid it by coming off the gas manually selecting 3 and then dropping it back into drive once the rev range has gone up. Not sure if manually selection in this instance will cause any other problems? Ive searched the forum but cant find any similar problems being reported. Ive read a couple of possible fixes that might work, including greasing yolk ( it has a single piece tailshaft and its not a stop go issue), disconnecting battery ( but i assume this will do nothing to reset the pcm) or getting a reflash of the pcm. Its almost due for a transmission service but i suspect this wont do anything but i'll get thst donrt. I ve also read that the transmission pcm stores shift data and it is used to provide optimum shifting. So given we are regularly going from towing to no towing perhaps this is part of the problem.

Any words or wisdom would be greatly appreciated or possible fixes i can do on the run. Were a few hundred miles from the closest dealer.

Cheers chris