I bought a 2004 Rancher AT for my teenager son. The machine only has 500Miles, but needed some love. It needed front CV Boots (because of a 2 inch lift), ended up replacing one of the axles because the CV cup was badly warn and couldn’t get the clip out of it. It also needed front and rear brakes, no big deal. The rears were very difficult to get apart, but we eventually got it.

Once we got the brakes and front axles back into it we drove it around the yard and all seemed to be good, but before taking it out for a long ride I wanted to replace the engine oil and also do the differentials. This too, was no big deal as I have a older Forman 450 and the procedure was the same.

I only use honda oil in my machines, but now after the oil change we have noticed what I guess is the transmission slipping. It will click under load and not go anywhere. It is worse in AT mode, but will also slip while in ESP mode.

I have read all the forums on the transmission slipping problems and it seems that for most people the slipping happens when the engine is hot, but in our case it slips the most when the engine is COLD. When the engine gets hot it slips much less.

Is this the typical Rancher 400 AT transmission problem?

The crazy thing is we didn’t notice this problem before the oil change. I used normal honda oil, should I switch to "winter" oil as it seems to get better when the oil is hot (thins out).

Looking for advice, is it the clutch, angle sensor, or ECM?
Why is it worse when cold? Could it be the oil pump?

Having bought this used, I don’t know if the ECM recall has been done, is there any what I can tell?

Thanks for any help
Larry