4l60e shift issues

[lolxnico]

Hey guys I’ve been look all over the forums looking for an anwser, I suspect the 3-4 clutches went out on my 98 k1500 with the 4l60e, fluid is red an looks to be about 2 quarts higher than it should be, it shifts from first to second no problem but when going into third it shifts down to first, it’s not like neutral I can still get power but revs like in first gear, when I unplugged the harness from the trans I’m in default 1st and not 3rd. Anyone have any ideas?

 

[NickTransmissions]

Hey guys I’ve been look all over the forums looking for an anwser, I suspect the 3-4 clutches went out on my 98 k1500 with the 4l60e, fluid is red an looks to be about 2 quarts higher than it should be, it shifts from first to second no problem but when going into third it shifts down to first, it’s not like neutral I can still get power but revs like in first gear, when I unplugged the harness from the trans I’m in default 1st and not 3rd. Anyone have any ideas?

Yank it out and rebuild it. You're correct with your diag, no need for any other ideas.

If you want to be 100% sure, plug in a scan tool that can show live transmission data, drive it and watch the gear shift data. If the PCM commands a shift to 3rd but you end up in first, you have your answer.

Why is the fluid 2 quarts higher than it should be?

 

[lolxnico]

Thanks for the reply, just needed someone else to confirm so my mind stop wandering lol. I just bought it from another guy who lied to be about everything being good, I didn’t add any fluids so I assume he overfilled it when he did the rear main