I've been using the AXYC base manual tranny BIN for my DIY tuning and the AUJP memcal for the limp home mode with my Super Ram 383. Originally the car had a stock 3.42 posi rear with the factory 5 speed. Since I went to a Ford 9" with 4.11 gears, my shift light's operation has a strange anomally.

I've got the Tunercat $8D version that has some tuneable parameters for the shift light, so I can change the RPM points where it can come on (raised them a bit long before the Ford 9" was installed).

The strange thing is this: Once you hit that RPM in 5th gear, the shift light still comes on. It never did this before the gear change, so I don't understand why it is doing it now.

The only change that occurred when this started was the 4.11 install and the accompanying install of the Dakota Digital box so that the ECM and speedo see correct vehicle speeds.

RBob - or anyone else - any idea why this may be occuring?

If it's affecting the shift light, it could also be affecting the TCC lockup for the auto folks too, couldn't it? Don't they use the same basic code in the ECM for both?

im not sure about yours, but some GM ecms look at the MPH and the RPM and use a lookup to decide what gear you're in.


since you changed gearing, and probly didnt change the lookup table(s), it thinks you're in 4th instead of 5th, and you get the upshift light.




btw, how fast are you going to hit the shiftredline in 5th?

Don't know yet on the about the speed at red line in 5th, probably never will!!!!

Any idea where I can find some info on these other values/tables? I'd sure like to fix things "right"....

You forgot to add the 6th gear

I've looked over allot of the TCC and shift light stuff in $8D and still do not have a full handle on it.
There are allot of index parameters that throw me off track when going though it.
I do see items such as gear ratio at location
82FC (1st gear = 255 in AUJP)
82FD (4th gear max ratio = 3.70 in AUJP)
82FE (4th gear min ratio = 2.80 in AUJP)

The C.A.R.S. light also relies on input from the TPS and MAP to determine shift points. There is a selection bit that can be made to rely on RPM or MPH for the calc (just couldn't find it at the moment)
The routine where the calculations are done is at DF17 in AUJP (DF0F in ANHT) Not sure where it is in your bin but the code should be the same for the most part and you could search for the common items to locate it exactly.
Wish I could shed more light on it cause I wanted to make the light functional on AUJP along with the TCC (would assign the light to another output address) but it got confused and I didn't stay with it.

Thanks for the reply. Unfortunately, I don't have a hack for AXYC, so I guess I'll try using the hex editor in TP and try to find the similarities you mentioned.

Appreciate the assistance! If I manage to figure something out I'll be sure to let everyone know......

I use XVI32 and type in a short hex string of interest from aujp then search bin xxxx to find the same string.
Worked quite well when I had to find a routine in aujp that was uncommented in the 58. A .lst file makes it even easier
The TP method will work fine for doing one bin.
But doing it on 6 bins would make you cross eyed.

edit:
Somebody posted a hex editor fix for the SL a while back.
I think it was for one rpm only though.

OK, I'll see if I can do it that way. THanks!!!

This was the thread Z' was talking about.
https://www.thirdgen.org/techbb2/sho...ht=shift+light

I need to look into this output stuff again. I want the light to work with an auto (using the tables/variables in the bin)
AND
I want to make a knock light too! (have it figured what I want to do just need the output