!!!!!Will not WOT shift to 3rd if starting in 1st!!!!!!

I just took the car up the street and this is what I found if I start a pull in 1st gear (stopped or rolling) it WILL NOT make the 2-3 shift, however if I start the pull in 2nd gear it will (or if I lift the throttle and get back in it). When the pull is started in 2nd gear the 2-3 shift happens pretty close to where I command it just like the 1-2 shift does. I just cant figure out what would cause an issue like this. I called RPM and they said either clutches or tune, but the trans is brand new (less than 50 miles). With the longer 1st gear and my stall my RPM only drops to 5500 on the 1-2 shift I wonder if thats not enough time for the computer to command the shift??


Car details
Rpm lvl7 with 2.84 planetary
Coan 4500
LS3 swap
Custom S480 turbo setup

Thanks in advance!

LOG 2-3s is a start in 2nd gear
LOG 2-3s.1 is a 1st gear start ( I let off at 6800 to allow for the shift then got back in it)

 

I can email the config if you want.....that type of file will not attach here.

 

As a side note the 2.84 planetary will require a change to the MPH shift tables since both 1st and 2nd now have different gear ratios from stock.
I don't see how that could change when/whether the 2-3 shift occurs depending upon whether you start in [OD] or [D2].
As I understand it, if you start in [D2] and then move to [D3] the 2-3 shift occurs as programmed?

You may need to log with a scanner to see if/when the shift is commanded.

 

Yea I have logged WOT throttle runs in each gear in order to get my mph settings for the shift points. I have never set up my scanner to log any type of trans parameters maybe I could try doing this.

Also to clear up any confusion all of my tests have been performed with the shifter in Drive/3

When I say a second gear pull I'm trying to say that I start at a high enough speed so the car doesn't downshift into 1st. If I'm going slow enough for it to shift to 1st then the 2-3 shift won't happen

 

I have seen this before. It is most likely the fluid level is low. Try adding another 2/3 of a quart and see what happens. If adding the extra fluid solves it remark the dipstick to the new correct level. If you have access to a 0-300 psi. gauge and air is getting into it, the pressure will not be steady, it will fluctuate.

 

Haven't checked the fluid level since the first startup and initial trans fill so I will definitely look into this.

Thanks

 

I checked fluid at operating temperature and it was coming out quickly after removing plug so the level is full to say the least.

Guess I will try to do some trans parameter logging next.

 

What plug did you remove??? Coming out of where?
It will act badly too if overfull.

 

My trans has the deep pan on it and the fill plug on the side of the pan near the rear of the pan towards the top on the driver side.

 

When mine was doing exactly what you are describing a deeper pan is what solved the issue.

see this: https://ls1tech.com/forums/automatic...are-fixed.html

 

Put a 0-300 psi. gauge on it and you will see what going on.

 

Yep checking line pressure is the last thing I can do I guess.

 

Not sure why I haven't thought to mention this yet but this same transmission was in my car before the turbo build and it would make the 2-3 shift at wot then. I pulled the trans and sent it to RPM for a refresh and had the converter restalled during the turbo install. So as far as it being the tune I highly doubt it could be which sucks because I was really hoping it was something simple. Looking back at some old logs, they show the 2-3 shift happening so this issue has only occurred after the trans rebuild and new stall.....