4l60e 1st - 2nd wierd shift at little throttle

[CRF450R]

So I have 350 900km on my original 4l60e and all of a sudden today it decided to act up for about a hour now shifts like new again. So on my way back from picking up my rebuilt motor about 5 hours I rolled into Saskatoon and my first set of lights I noticed a weird shift from 1-2nd gear it felt like my locker locking but after a few more red lights I realized it was my trans my truck rarely gets past 3k for rpms I drive like a old guy I then kept on my way stopped in at a friend's place about a hour west of Saskatoon truck sat for couple hours hopped in drove home truck drove 35 minutes home and trans didn't skip a beat I stopped and tried to get it to SoCal shutter again but it just won't. Is this something too worry about? The oil looks as good new oil and it's right at the full line.

 

[df2x4]

So I have 350 900km on my original 4l60e

Is this something too worry about?

Yes.

Your definition of a weird shift is confusing though. Were the engine RPMs not matching the wheel speed? If so that's definitely a problem.

EDIT - Side note, what fluid do you have in the trans? I remember you posting about switching over to John Deere fluids recently. I'm not familiar with everything they offer but a 4L60E needs GM Dexron 6 (ideally) or Dexron 3.

 

[CRF450R]

Yes.

Your definition of a weird shift is confusing though. Were the engine RPMs not matching the wheel speed? If so that's definitely a problem.

EDIT - Side note, what fluid do you have in the trans? I remember you posting about switching over to John Deere fluids recently. I'm not familiar with everything they offer but a 4L60E needs GM Dexron 6 (ideally) or Dexron 3.

That's the only thing left that currently isn't running JD fluid as of yet rest of the truck is all JD. Well I was stopped at a red light and when I got the green I slowly accelerated and when it went to go shift into second its like there was a quick shutter kinda the same feeling as a locker locking it did it every time I stopped now this was after five hours of driving. The rest of the gears shift no problem dove another hour to a friend's place and parked the truck ( off) for couple hours while I was visiting the truck cooled down and when I left to drive another 35 min home the trans shifted perfectly I stopped a couple times to see if it would do it it never did seems to be working good again. So I'm not sure what to think I took my last 4l60e too 400 000km was hoping this one would go that long aswell I also have no engine lights or nothing on.