I'm having some weird tranny issues! At times, the truck doesn't want to downshift. If I manually select a lower gear, it's fine.

I was having a whole lot of SES codes when I did the cam, and I was told by some local LS1 buddies that the SES light can foul up the converter's functions, so I thought that might be the culprit. But, now that the idle is better, I'm only getting the Misfires code every now and then, and it usually goes out very shortly. Last night it did it again, and there was no SES light.

Anyone have any ideas? What steps can I take to correct this problem? Rebuild? 4L65E? Lightning? (j/k)

 

Scream, no new 14 sec time slips yet? How did you finaly fix the idle issue? I may be wrong but I think down shifts are controlled by throttle position, and speed. Have you tried setting your shift pionts up higher? That may let it down shift at higher RPMs.

 

I haven't changed any settings on the HPPIII, so I don't think that has anything to do with it. The truck was shifting fine with the HPPIII .

Does anyone have any thoughts?

 

Do you know what codes were/are being thrown?

I've looked through my LS1Edit file and just about all the trans functions are controlled by throttle position in some way. I've heard misfire codes will cause converter problems also. If you run a search in the Drivetrain section maybe you could find some info on that.

I'd say it probably has something to do with the codes but, it could just be something mechanically wrong.

My $.00

Don't be joking about getting a Lightning now.

 

Well, it's doing it now and there aren't currently any codes showing--the light is off and there aren't any codes stored in the PCM.

I'll do some more searching...thanks!