t72ss402

iTrader: (10)

I just finished my swap in my 79 Malibu and got it tuned. The transmission shifts fine under normal driving, but under wide open throttle it will not shift from 2nd to 3rd. Any ideas guys? Thanks in advance.

Tim.

Jake's Performance

iTrader: (2)

If I you want a good answer you have to give more info. What trans for starters? Fluid level good, shifter adjusted properly?

01ssreda4

iTrader: (96)

Plus is it tuned for the trans? Whats the command 2/3 shift, and whats your rev limiter set at?

t72ss402

iTrader: (10)

"Jake's Performance If I you want a good answer you have to give more info. What trans for starters? Fluid level good, shifter adjusted properly?"

Sorry the trans. is a 4L60E, fluid level is good and shifter shifts properly when manually shifting through the gears.

"01ssreda4 Plus is it tuned for the trans? What's the command 2/3 shift, and what's your rev limiter set at?"

I had the tuner check to make sure that the tune is set up for the 4L60E (old combo had a 4L80E so that was my first thought) but he said he set up right. He said the computer is giving it the command to shift but it will not. Almost like the solenoid is not switching, but it operates perfect during normal driving.

Rev. limiter is set at 6800 rpm.

Thanks guys.

01ssreda4

iTrader: (96)

I realize its being commanded to shift....but WHEN. Like at what rpm? Its critical that mph requirement is met first, and the rpm commanded has enough time before clipping the limiter. Even with a healthy 4l60e you may see delays of 3/400 rpms between when you ask for a shift and when it actually completes. You MUST compensate for this in the tune. 1/2 seems more dead on with only a slight delay of maybe 50-100rpm, and the hotter the trans fluid the quicker it can shift. As an example, I would command 2/3 at 6150 and it would complete between 6400-6500 with a redline of 6750. This is a comfortable room for error IMO.

t72ss402

iTrader: (10)

Thank you, I will get with my tuner and find out where he set the 2-3 shift point.

01ssreda4

iTrader: (96)

Back to the mph first, I command mph that is the equivalent of say 5900 rpms (since I know I'm commanding around 6100 rpms), so if I'm at 62mph at 5900, then I set wot shift to 62mph, 6150rpm, and shift completes between 64-6500. This way it clips mph first then rpm. Also, there are multiple places to input your wot shifting, and they all need to match.

mrvedit

Yes! Set the WOT shift-MPH to a number corresponding to a very modest RPM. (Its 6000 for me, 1000 less than my normal shift).
Also make sure the WOT shift-MPH is duplicated for the 100% throttle value in the partial-throttle shift table.

This way the trans will shift at the tuned RPM (+ or -) and you don't have to worry about the exact MPH.