Shifts great n/a, not so great w/100shot

[snettell]

LS1 H/C/I 400RWHP N/A
RPM level 5 4l60E
3600 miles on build
Yank SS 3600 stall

Been dealing with this 2-3 shift issue for some time now and it has never been right. At the strip the car shifts perfect and is very consistent on just motor. When I try to hit it with a 100hp shot it hangs and hits the rev limiter until I lift. About 500 miles ago I took the trans out and sent it back to RPM. They tore it apart and said it was fine so I'm thinking it must be the tune. Im not a tuning expert but have tried minor adjustments to some of my trans tables. Nothing has worked. Help Please!!!!

[Lakegoat]

I would try dropping the 2nd to 3rd shift speed down about 5mph or so. You have it at 81 mph at 6450. Your log shows 82mph at 6400 which is really close. Using the nitrous and taking into consideration that it takes some time for the trans to actually complete the shift, I think it should be about 76 mph. Be sure and change all full throttle tables. On my 4L80, I have the desired shift times set to .125 on my drag tune. My street tune is a little softer.

[snettell]

Thanks for replying Lakegoat. You may be right about the shift speed being too close. From my reading other threads 5mph early and wait for the commanded rpm seems to be what is recommended. I have tried adjusting my shift speeds but I may have adjusted the speed and the shift rpm together. Do you have all your shift times set at .125 on your drag tune? At one point I had them all set to zero but have since changed them to what they are now. Neither setting has worked. Appreciate the help.

Anyone else see anything that is not right. I haven't done much with shift pressures nor force motor changes. Not sure what adjustments should or need to be made to those.

[Joshtuning]

You should get a rpm nitrous controller where it only throws nitrous at certain rpms let's say from launch to your shift point

[snettell]

Thanks Joshtuning. I do have nitrous controller installed. In talking to people they have recommended that I spray through my shift point, so thats what I have been doing. That was actually my next thing to try. Lowering the cutoff to a few hundred rpm below my shift and see what happens. Not really what I want though as it just masks my real issue.

[Lakegoat]

I have the speeds at .125 for all the drag shift speeds now, and also tried 0. Didn't make any difference in the shifting as far as I could tell. My trans is modified internally so that may be the reason.
That's interesting about the controller. Being able to set it to reduce nitrous during the shift would make it easier on the trans. I just use a button but I am only spraying a 100 shot.

[snettell]

Thanks Lakegoat. I've got a few things to try now. Hoping to go to the track in a couple weeks. The one change I have made is put a deeper trans pan with a filter extension. Gunna try that first then try some of the suggestions I have gotten.

[snettell]

I got an opportunity to get the car out to check line pressures on the car today.
With trans temp at normal operating temp of about 150F these are the numbers I got:

Park 70# @ 950rpm
Reverse 165# @ 950rpm
Neutral 70# @ 950rpm
1st gear 115# @ 950rpm
2nd thru OD 90-100# @ 950rpm

1st gear @ 6500rpm 150#
2nd gear @6500rpm 175#

Didn't do third gear.


Since the numbers were lower than I was told they should be, I unplugged the trans control plug and tested again.

With the control plug remove I could not move the car in 1st gear. (Not sure why).

Put the shifter into OD at idle I got 240# of line pressure.

Wasn't able to do anymore than just idle around. Really thought I was going to wreck something.

The WOT numbers are quite a bit lower than I was told they should be.

Since the line pressure went up with the trans control plug removed am I to believe is this a tuning/sensor issue or a mechanical issue.

I really have no idea how to diagnose transmission issues.

Really need some advise on what to do next

[snettell]

Thanks Big Mike,
I currently have all torque management zero'd out and my actual trans pressure at my shift points is about 220. I've got to do more testing to see if that is high enough. Hoping to get to the track this weekend however they are predicting rain. Hope they are wrong. I've lowered my shift mph to 76mph and also lowered my shift times down a little. My last scan says my trans delivered torque at my shift points is between 300 and 320. May have to bump up the shift pressure in those cells. Appreciate the help

[snettell]

Thanks again BigMike. Could you please give more detail. Still not very good with tuning.
Delivered torque to low, part of the problem. Please explain?
eq ratio table. Are you talking about the torque reduction table or ?
oncoming preset and #2 cell. Dont know what this is.

[BigMike42]

Nevermind, ignore my posts, for some reason I thought you had a 6l80e. I would reach on to wacker at 6l80e, he probably knows a ton about your transmission too. Deleted my posts.