[projectblackbird]

I have a stock 99 camaro with a brand new transmission, less that 200 miles. It shifts fine at part throttle, but skips 2nd gear all together at wide open throttle if you leave the shift in drive or overdrive. If you move the shift manually, it bangs every gear flawlessly. Any ideas on what could be causing this?

 

[262]

sounds like a tuning issue.

 

[deadhorse66]

Either that, or you have a check ball lodged in the separator plate would be my most immediate guess. You can get the bonded GM separator and a set of torlon check balls to stop this from happening again if it is indeed the problem.

 

[projectblackbird]

I have ruled tuning out, as I am a tuner. I have thrown every possible combination at it and it still does the exact same shift.

Check ball huh? Could it be possible it's just a piece of debris from the build? Like I said it doesn't have 200 miles on it.

 

[deadhorse66]

I suppose it could be, anything is possible but that would have to be a huge piece of debris. Do you know if the builder replaced the separator? I've had wear on the separator plate (root) cause this, but I can't recollect the location of the check ball that does it. If you need me to do some digging, shoot me a PM and I'll get back to you.

 

[262]

If it shifts part throttle and not wot 9 out of 10 times its tuning. What band? What band clearance? Drum finish? How is 4th gear? What does a logger say? Does it command the shift and not shift or is it not even being commanded. That right there will tell the story.

 

[projectblackbird]

I have no idea what band or clearance and finish. I try not to tear into transmissions, too many little pieces that have to go back in. I checked the data log last might after a pull and it commanded 2nd but failed. This transmission was purchased from a reputable transmission shop.

 

[rain man]

GM changed the separator plate somewhere around there or a little bit after 99.

Its been a while since i had one apart, but i remember in the early 2000's GM had a new part number that supposedly superceded the old plate in the early LS cars and was supposed to do the job, yet it wasnt right on some of the valve body passages, there was barely enough overlap.

Some passages in the vb had minor changes.

The newer pn plate was ok for the newer vb , but didnt sit right with me being used on the old vb, despite it coming up in GM's shit as the right part for the job.

Anyway I never ended up using the new separator plate for this reason. Im sure some could miss it though.

Im not saying it is this but if you can find out if the separator plate was changed, and perhaps if you cant solve this externally or someone else can chime in with an idea, you might want to pull the vb at least and check the separator plate fit, and the other things people already mentioned.

 

[262]

things happen. If it commands the shift and doesnt happen then it is mechanical. I would start by checking the 2nd gear servo seals. Also, check servo pin travel.

 

[93jrh]

If it shifts correctly shifting it manually your problem is going to be in the
valve body, stuck valve, wrong plate, wrong gaskets or a shift kit that
is not installed correctly. you can use a plate from a 96 to 06 model with
the late model gaskets.

 

[projectblackbird]

Today, i am pulling the transmission out of the car and sending it back to the shop that built it, as it is still under warranty. I will update when i get it back and reinstalled.
:-damnit

 

[Morris Race Trans]

They might have wanted to road test it. Pressure test it or scan themselves.